25/30 EFI

25/30 EFI & 25 EFI Jet

& 25 EFI Jet

S ERV IC E M A N U A L
S ERVI CE

MANUAL

www.mercurymarine.com.au www.mercurymarine.com www.brunswick-marine.com

41-71 Bessemer Drive P.O. Box 1939 Parc Industriel de Petit-Rechain
B-4800 Verviers, Belgium
MARCH 2016
90-8M0105568

Dandenong South, Victoria 3175 Australia Fond du Lac, WI 54936-1939 USA

© Mercury Marine. All rights reserved. 90-8M0105568 MARCH 2016

Printed in U.S.A.
Notice to Users of This Manual
Throughout this publication, warnings, cautions, and notices (accompanied by the International HAZARD Symbol !
) are
used to alert the mechanic to special instructions concerning a particular service or operation that may be hazardous if
performed incorrectly or carelessly. Observe them carefully!
These safety alerts alone cannot eliminate the hazards that they signal. Strict compliance to these special instructions when
performing the service, plus common sense operation, are major accident prevention measures.

! WARNING
Indicates a hazardous situation which, if not avoided, could result in death or serious injury.

! CAUTION
Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.

NOTICE
Indicates a situation which, if not avoided, could result in engine or major component failure.

IMPORTANT: Identifies information essential to the successful completion of the task.

NOTE: Indicates information that helps in the understanding of a particular step or action.
This manual has been written and published by the Service Department of Mercury Marine to aid our dealers’ mechanics and
company service personnel when servicing the products described herein. We reserve the right to make changes to this
manual without prior notification.
It is assumed that these personnel are familiar with marine product servicing procedures. Furthermore, it is assumed that they
have been trained in the recommended service procedures of Mercury Marine power products, including the use of mechanics’
common hand tools and the special Mercury Marine or recommended tools from other suppliers.
We could not possibly know of and advise the marine trade of all conceivable procedures and of the possible hazards and/or
results of each method. Therefore, when using a service procedure and/or tool that is not recommended by the manufacturer,
be completely satisfied that neither your personal or product safety is endangered.
All information, illustrations, and specifications contained in this manual are based on the latest product information available at
the time of publication. As required, revisions to this manual will be sent to all dealers contracted by us to sell and/or service
these products.
Refer to dealer service bulletins, operation maintenance and warranty manuals, and installation manuals for other pertinent
information concerning the products described in this manual.

Precautions
It should be kept in mind, while working on the product, that the electrical and ignition systems are capable of violent and
damaging short circuits or severe electrical shocks. When performing any work where electrical terminals could possibly be
grounded or touched by the mechanic, the battery cables should be disconnected at the battery.
Any time the intake or exhaust openings are exposed during service they should be covered to protect against accidental
entrance of foreign material into the cylinders which could cause extensive internal damage when the engine is started.
During any maintenance procedure, replacement fasteners must have the same measurements and strength as those
removed. Numbers on the heads of the metric bolts and on the surfaces of metric nuts indicate their strength. American bolts
use radial lines for this purpose, while most American nuts do not have strength markings. Mismatched or incorrect fasteners
can result in damage or malfunction, or possibly personal injury. Therefore, fasteners removed should be saved for reuse in the
same locations whenever possible. Where the fasteners are not satisfactory for reuse, care should be taken to select a
replacement that matches the original.

Replacement Parts
Use of parts other than the recommended service replacement parts will void the warranty on those parts that are damaged as
a result.

! WARNING
Avoid fire or explosion hazard. Electrical, ignition, and fuel system components on Mercury Marine products comply with
federal and international standards to minimize risk of fire or explosion. Do not use replacement electrical or fuel system
components that do not comply with these standards. When servicing the electrical and fuel systems, properly install and
tighten all components.

Page i © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

Cleanliness and Care of Product
A Mercury Marine power product is a combination of many machined, honed, polished, and lapped surfaces with tolerances
measured in the ten thousands of an inch/mm. When any product component is serviced, care and cleanliness are important. It
should be understood that proper cleaning and protection of machined surfaces and friction areas is a part of the repair
procedure. This is considered standard shop practice even if not specifically stated.
Whenever components are removed, they should be retained and marked for installation into their original locations. During the
assembly process, the marked parts are quickly identified for installation into the same locations they were removed from.
Personnel should not work on or under an engine that is suspended. Engines should be secured to work stands, or lowered to
the ground as soon as possible.

Copyright and Trademark Information

© MERCURY MARINE. All rights reserved. Reproduction in whole or in part without permission is prohibited.
Alpha, Axius, Bravo One, Bravo Two, Bravo Three, Circle M with Waves Logo, K‑planes, Mariner, MerCathode, MerCruiser,
Mercury, Mercury with Waves Logo, Mercury Marine, Mercury Precision Parts, Mercury Propellers, Mercury Racing,
MotorGuide, OptiMax, Quicksilver, SeaCore, Skyhook, SmartCraft, Sport‑Jet, Verado, VesselView, Zero Effort, Zeus, #1 On the
Water and We're Driven to Win are registered trademarks of Brunswick Corporation. Pro XS is a trademark of Brunswick
Corporation. Mercury Product Protection is a registered service mark of Brunswick Corporation.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page ii

 1
Manual Outline
Important Information

1 - Important Information
A - Master Specifications
B - Maintenance
C - General Information
Electrical
2
3
D - Outboard Installation
Fuel System
2 - Electrical
A - Ignition
B - Charging and Starting System
C - Timing, Synchronizing and Adjustments Powerhead
4
5
3 - Fuel System
A - Fuel System Operation
Mid-Section
B - Troubleshooting and Diagnostics
C - Service Procedures
D - Emissions
4 - Powerhead
Lower Unit
6
7
A - Cylinder Block/Crankcase
B - Cylinder Head
Attachments
C - Oil Pump
D - Cooling System
5 - Mid-Section
A - Clamp/Swivel Bracket, Driveshaft Housing
Manual Starter
8
9
B - Power Trim
C - Gas Assist Manual Trim/Tilt
Jet Drive Outboard
6 - Lower Unit
A - Gear Housing
7 - Attachments
A - Throttle/Shift Linkage
B - Tiller Handle
8 - Manual Starter
A - Recoil Starter
9 - Jet Drive Outboard
A - Jet Drive Outboard

Page iii © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page iv
 Master Specifications

Important Information
1
Section 1A - Master Specifications A
Table of Contents
25/30 Master Specifications...............................................1A-2 Oil System Specifications .......................................... 1A-5
Model Specifications...................................................1A-2 Cylinder Head Specifications......................................1A-5
Fuel System Specifications.........................................1A-2 Power Trim Specifications.......................................... 1A-7
Ignition Specifications................................................. 1A-3 Gearcase Specifications............................................. 1A-7
Charging and Starting Specifications..........................1A-3 Propeller Chart...................................................................1A-7
Cylinder Block/Crankcase Specifications................... 1A-4 25 HP 3 Cylinder EFI Propeller Information Chart......1A-7
Cooling System Specifications................................... 1A-4 30 HP 3 Cylinder EFI Propeller Information Chart......1A-8
Piston Specifications...................................................1A-5

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1A-1

Master Specifications

25/30 Master Specifications

Model Specifications
Model Specifications
18.4 kW (25 hp)
Kilowatts (Horsepower)
22.1 kW (30 hp)
Displacement (All HP) 526 cc (30.02 cu in.)
Weight
25 MH 71 kg (157 lb)
25 ERC 72 kg (159 lb)
25 MLH 74 kg (163 lb)
25 ELRC, 25 EH 75 kg (165 lb)
25 ELH, 30 MH GA 78 kg (172 lb)
30 MLH GA 81 kg (179 lb)
25 ELPT, 30 ELRC GA, 30 ELPT 82 kg (181 lb)
25 ELHPT, 30 ELH GA, 30 ELHPT 85 kg (187 lb)
25 Jet MLH GA 87 kg (191 lb)
25 Jet ELH GA 90 kg (198 lb)
25 Jet ELPT 89 kg (196 lb)
Transom height
Short shaft 38.1 cm (15 in.)
Long shaft 50.8 cm (20 in.)
Engine type FourStroke
Number of cylinders 3
Firing order 1, 3, 2
RPM
Idle 850 ± 25 RPM in gear
25 Jet idle 850 ± 25 RPM
18.4 kW (25 hp) wide‑open throttle 5000–6000 RPM
22.1 kW (30 hp) wide‑open throttle 5250–6250 RPM
25 Jet wide‑open throttle 5000–5500 RPM
Exhaust system Through‑prop

Fuel System Specifications

Fuel System Specification
Fuel system Computer controlled sequential multiport electronic fuel injection
Fuel type Refer to Section 1C ‑ General Information—Fuel Requirements
Mechanical plunger, diaphragm
Fuel pump type
Electric
Fuel pump pressure (mechanical) 29 kPa (4.2 psi)
Fuel pump pressure (electric) 294 kPa ± 10% (42.6 psi ± 10%)

Page 1A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Master Specifications

Ignition Specifications
Ignition Specifications at 20 °C (68 °F)
Ignition type Computer controlled CDI (capacitor discharge ignition)
Spark plug NGK DCPR6E
Spark plug gap 0.8–0.9 mm (0.031–0.035 in.)
Firing order 1, 3, 2
Ignition timing at idle 5° ± 5° BTDC
Ignition timing at WOT 38° BTDC
RPM overspeed 6300 RPM
ECM RPM limiter (Guardian) 2800 RPM
Over temperature 90 °C (194 °F)
Low oil pressure (over 5 seconds) 24.5 kPa (3.5 psi)
Crankshaft position sensor 148–222 ohms
Ignition coil
Primary 0.17–0.23 ohms
Secondary 3.3–4.9 k ohms
Spark plug lead (between spark plug cap and black lead) 7.1–11.1 k ohms

Charging and Starting Specifications

Charging and Starting Specifications
Alternator type Three phase
Alternator charge coil resistance 0.29–0.43 ohms
Alternator output at 850 RPM 5.5 A
Alternator output at 5000 RPM 15 A
Starter
Type Bendix
Output 0.6 kW at 12 V
Brush length 12.5 mm (0.49 in.)
Brush length (service limit) 9.5 mm (0.37 in.)
Commutator undercut 0.5–0.8 mm (0.02–0.03 in.)
Commutator diameter 30 mm (1.18 in.)
Commutator diameter (service limit) 29 mm (1.14 in.)
Fuse capacity 20 A
Fuse type Mini fuse
Battery requirements (minimum)
Above 0 °C (32 °F) 465 marine cranking amps (MCA) or 350 cold cranking amps (CCA)
Below 0 °C (32 °F) 1000 marine cranking amps (MCA) or 775 cold cranking amps (CCA)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1A-3

Master Specifications

Cylinder Block/Crankcase Specifications

Cylinder Block/Crankcase Specifications
Number of cylinders 3
Displacement 526 cc (32.09 cu. in.)
Standard bore 61.0 mm (2.4016 in.)
Standard bore (service limit) 61.06 mm (2.4039 in.)
Cylinder bore maximum taper (service limit) 0.08 mm (0.0032 in.)
Cylinder bore maximum out of round (service limit) 0.06 mm (0.0024 in.)
Crankshaft main bearing journal 35.99 mm (1.4169 in.)
Crankshaft main bearing journal (service limit) 35.97 mm (1.4161 in.) or less
Crankshaft pin journal 29.98 mm (1.1803 in.)
Crankshaft pin journal (service limit) 29.95 mm (1.179 in.) or less
Crankshaft end play 0.05–0.15 mm (0.002–0.006 in.)
Crankshaft runout Less than 0.05 mm (0.002 in.)
Crankshaft runout (service limit) 0.05 mm (0.002 in.) or more
Crankshaft main bearing oil clearance 0.012–0.044 mm (0.0005–0.0017 in.)
Crankshaft main bearing oil clearance (service limit) 0.06 mm (0.002 in.) or more
Crankshaft pin bearing oil clearance 0.010–0.036 mm (0.00037–0.00142 in.)
Crankshaft pin bearing oil clearance (service limit) 0.060 mm (0.002 in.) or more
Connecting rod wrist pin bore diameter 16.01–16.04 mm (0.630–0.631 in.)
Connecting rod wrist pin bore diameter (service limit) 16.04 mm (0.631 in.) or more
Connecting rod crankshaft pin diameter 29.995–30.021 mm (1.1809–1.1819 in.)
Connecting rod crankshaft pin diameter (service limit) 30.023 mm (1.182 in.) or more
Connecting rod side clearance 0.1–0.25 mm (0.004–0.01 in.)
Connecting rod side clearance (service limit) 0.6 mm (0.0236 in.)

Cooling System Specifications

Cooling System Specifications
Cooling system Water cooled ‑ thermostat control
Thermostat
Start to open temperature 60° ± 1.5 °C (140° ± 3 °F)
Full open temperature 75° ± 1.5 °C (167° ± 3 °F)
Valve lift 3 mm (0.12 in.)

Page 1A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Master Specifications

Piston Specifications
Piston Specifications
Piston skirt standard diameter 60.96 mm (2.40 in.)
Piston skirt standard diameter (service limit) 60.90 mm (2.3976 in.)
Piston to bore clearance 0.020–0.055 mm (0.0008–0.0022 in.)
Wrist pin diameter 16.0 mm (0.63 in.)
Wrist pin diameter (service limit) 15.97 mm (0.629 in.)
Top ring side clearance 0.04–0.08 mm (0.0016–0.0031 in.)
Top ring side clearance (service limit) 0.1 mm (0.004 in.)
Second ring side clearance 0.03–0.07 mm (0.0012–0.0028 in.)
Second ring side clearance (service limit) 0.09 mm (0.0035 in.)
Oil ring side clearance 0.05–0.15 mm (0.002–0.0059 in.)
Oil ring side clearance (service limit) 0.17 mm (0.0067 in.)
Top ring end gap 0.15–0.30 mm (0.0059–0.0118 in.)
Top ring end gap (service limit) 0.5 mm (0.02 in.)
Second ring end gap 0.35–0.50 mm (0.0138–0.0197 in.)
Second ring end gap (service limit) 0.7 mm (0.028 in.)
Oil ring end gap 0.2–0.7 mm (0.008–0.028 in.)

Oil System Specifications

Oil System Specifications
Oil pump type Trochoid
Oil type
All temperatures FC‑W 10W30
Alternate viscosity above 4 °C (40 °F) FC‑W 25W40
Oil capacity 1.8 liter (1.9 U.S. qt)
Engine oil pressure at 75 °C (167 °F)
at 850 RPM 150 kPa (21 psi) or greater
at 5000 RPM 300 kPa (42 psi) or greater
Oil pump housing inside diameter (service limit) 40.8 mm (1.606 in.)
Outer rotor to oil pump housing inside diameter clearance (service limit) 0.25 mm (0.01 in.)
Outer rotor height (service limit) 14.96 mm (0.589 in.)
Rotor to oil pump cover clearance (service limit) 0.11 mm (0.0043 in.)
Inner rotor to outer rotor clearance (service limit) 0.16 mm (0.006 in.)

Cylinder Head Specifications

Cylinder Head Specification
Maximum deck warp 0.1 mm (0.004 in.)
Number of valves 6
Number of valves per cylinder 2
Number of cams 1
Camshaft bearing outside diameter
Pulley side 17.98 mm (0.708 in.)
Pulley side (service limit) 17.95 mm (0.707 in.)
Oil pump side 15.97 mm (0.629 in.)
Oil pump side (service limit) 15.95 mm (0.628 in.)
Cam lobe height
(25) Intake and exhaust 23.87 mm (0.9398 in.)
(25) Intake and exhaust (service limit) 23.60 mm (0.9291 in.)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1A-5

Master Specifications

Cylinder Head Specification

(30) Intake and exhaust 24.28 mm (0.9559 in.)
(30) Intake and exhaust (service limit) 24.0 mm (0.9449 in.)
Valve lash
Intake 0.13–0.17 mm (0.005–0.007 in.)
Exhaust 0.18–0.22 mm (0.007–0.008 in.)
Valve seat angles 30°, 45°, 60°
Valve spring free length 35 mm (1.38 in.)
Valve spring free length (service limit) 33.5 mm (1.319 in.)
Valve stem diameter
Intake 5.48 mm (0.216 in.)
Intake (service limit) 5.46 mm (0.215 in.)
Exhaust 5.46 mm (0.215 in.)
Exhaust (service limit) 5.44 mm (0.214 in.)
Valve face width (intake and exhaust) 1.0 mm (0.04 in.)
Valve face width (service limit) 2.0 mm (0.08 in.)
Valve seat width 1.0 mm (0.04 in.)
Valve guide bore
Intake and exhaust 5.51 mm (0.217 in.)
Intake valve guide bore (service limit) 5.55 mm (0.218 in.)
Exhaust valve guide bore (service limit) 5.57 mm (0.219 in.)
Valve stem to valve guide clearance
Intake 0.008–0.04 mm (0.0003–0.0016 in.)
Intake (service limit) 0.007 mm (0.0028 in.)
Exhaust 0.025–0.057 mm (0.001–0.0022 in.)
Exhaust (service limit) 0.1 mm (0.004 in.)
Rocker arm shaft outside diameter 12.99 mm (0.511 in.)
Rocker arm shaft outside diameter (service limit) 12.94 mm (0.509 in.)
Rocker arm inside diameter 13.01 mm (0.512 in.)
Rocker arm inside diameter (service limit) 13.05 mm (0.514 in.)
Rocker arm shaft clearance 0.006–0.035 mm (0.0003–0.0014 in.)
Cylinder head upper camshaft bearing inside diameter 18.01–18.025 mm (0.709–0.710 in.)
Oil pump camshaft bearing inside diameter 18.01–18.025 mm (0.709–0.710 in.)
Valve stem seal color
Intake Black
Exhaust Green

Page 1A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Master Specifications

Power Trim Specifications

Power Trim Specifications
Trim up circuit pressure, maximum 13820 to 18430 kPa (2000 to 2675 psi)
Trim down circuit pressure 6500 to 8160 kPa (940 to 1180 psi)
System fluid Power Trim and Steering Fluid or Automatic Transmission Fluid (ATF) (Type Dexron III)
System fluid capacity 263 ml (8.9 fl oz)
Power trim and tilt motor
Voltage 12 VDC
Continuous run 60 seconds or less
Output 130 watts
Direction of revolution Forward/reverse
Circuit breaker
Type Bimetal
30 seconds or less 25 °C (77 °F)
On/reset time
20 seconds or more (25 A)
Brush length 10.0 mm (0.39 in.)
Wear limit 6.0 mm (0.236 in.)
Commutator
Outer diameter 19.5 mm (0.768 in.)
Outer diameter wear limit 18.5 mm (0.728 in.)
Depth of undercut 1.3 mm (0.051 in.)
Depth of undercut limit 0.8 mm (0.031 in.)
Tilt cylinder
Piston diameter 32.0 mm (1.260 in.)
Tilt rod diameter 12.5 mm (0.492 in.)
Stroke 140.0 mm (5.51 in.)

Gearcase Specifications
Gearcase Specifications
Gear ratio 1.92:1
Gearcase capacity 350 ml (11.8 fl oz)
Gear lubricant type Premium Gear Lubricant or GL5 SAE 80‑90 Weight
Pinion teeth 12
Pinion height 0.60–0.64 mm (0.023–0.025 in.)
Clutch Dog type (forward ‑ neutral ‑ reverse)
Forward, reverse teeth 23
Forward gear backlash 0.33–0.54 mm (0.013–0.021 in.)
Water pressure at idle 50 kPa (7.2 psi)
Water pressure at WOT 95 kPa (13.7 psi)

Propeller Chart
25 HP 3 Cylinder EFI Propeller Information Chart
• Wide–open throttle RPM: 5000–6000
• Recommended transom height: 50.8–63.5 cm (20–25 in.)
• Gear reduction: 1.92:1
• Right‑hand rotation (RH): standard

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1A-7

Master Specifications

No. of Approx. Gross Boat Approx. Boat Propeller Part

Diameter Pitch Material Speed Range
Blades Wgt. Length Number
Up to 4.8 m 38.6–54.7 km/h
9 12.5 3 Alum Up to 498.9 kg (1100 lb) 48‑896900A40
(16 ft) (24–34 mph)
408.2–635 kg 3.9–4.8 m 32.1–46.6 km/h
9.25 11 3 Alum 48‑896896A40
(900–1400 lb) (13–16 ft) (20–29 mph)
544.3–816.4 kg 3.9–5.1 m 25.7–38.6 km/h
9.5 9.5 3 Alum 48‑896892A40
(1200–1800 lb) (13–17 ft) (16–24 mph)
Up to 725.7+ kg 1.6–28.9 km/h
9.75 8 3 Alum 4.8+ m (16+ ft) 48‑896890A40
(1600+ lb) (1–18 mph)

30 HP 3 Cylinder EFI Propeller Information Chart

• Wide‑open throttle RPM: 5250–6250
• Recommended transom height: 50.8–63.5 cm (20–25 in.)
• Gear reduction: 1.92:1
• Right‑hand rotation (RH): standard

No. of Approx. Gross Boat Approx. Boat Propeller Part

Diameter Pitch Material Speed Range
Blades Wgt. Length Number
Up to 4.8 m 40.2–57.9 km/h
9 12.5 3 Alum Up to 589.6 kg (1300 lb) 48‑896900A40
(16 ft) (25–36 mph)
498.9–725.7 kg 3.9–4.8 m 33.7–49.8 km/h
9.25 11 3 Alum 48‑896896A40
(1100–1600 lb) (13–16 ft) (21–31 mph)
589.6–952.5 kg 4.2–5.4 m 27.3–41.8 km/h
9.5 9.5 3 Alum 48‑896892A40
(1300–2100 lb) (14–18 ft) (17‑ 26 mph)
Up to 816.4+ kg 1.6–32.1 km/h
9.75 8 3 Alum 4.8+ m (17+ ft) 48‑896890A40
(1800+ lb) (1–20 mph)

Page 1A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance

Important Information
1
Section 1B - Maintenance B
Table of Contents
Selecting Accessories for Your Outboard.......................... 1B-2 Engine Oil Capacity.................................................... 1B-8
EPA Regulations................................................................1B-2 Oil Changing Procedure............................................. 1B-8
EPA Emissions.................................................................. 1B-3 Changing Oil Filter ..................................................... 1B-8
Emission Certification Label....................................... 1B-3 Oil Filling..................................................................... 1B-9
Owner Responsibility.................................................. 1B-3 Checking Power Trim Fluid................................................1B-9
Inspection and Maintenance Schedule.............................. 1B-3 Corrosion Control Anode................................................... 1B-9
Daily Checks...............................................................1B-3 Propeller Replacement.................................................... 1B-10
After Each Use............................................................1B-3 Gearcase Lubrication.......................................................1B-12
Annually or 100 Hours................................................ 1B-3 Draining Gearcase....................................................1B-12
Three years or 300 Hours...........................................1B-4 Gearcase Lubricant Capacity................................... 1B-12
Battery Inspection ............................................................. 1B-4 Gearcase Lubricant Recommendation..................... 1B-12
Submerged Outboard........................................................ 1B-4 Checking Lubricant Level and Refilling Gearcase.... 1B-12
Exterior Care......................................................................1B-4 Lubrication Points............................................................ 1B-13
Flushing the Cooling System............................................. 1B-4 Jet Maintenance...............................................................1B-14
Flushing Jet Models....................................................1B-5 Worn/Dull Impeller.................................................... 1B-14
Top Cowl Removal and Installation................................... 1B-5 Impeller Clearance Adjustment.................................1B-15
Removal......................................................................1B-5 Impeller Removal and Installation.............................1B-15
Installation...................................................................1B-6 Shift Link Rod Adjustment........................................ 1B-17
Fuel System....................................................................... 1B-6 Corrosion Control Anode.......................................... 1B-18
Fuel Line Inspection....................................................1B-6 Lubrication Points..................................................... 1B-19
Fuel Filter (Low Pressure) ......................................... 1B-6 Storage Preparation.........................................................1B-21
Removal......................................................................1B-6 Protecting External Outboard Components.............. 1B-21
Installation...................................................................1B-6 Protecting Internal Engine Components................... 1B-21
Fuse Replacement ‑ Electric Start Models.........................1B-6 Gearcase.................................................................. 1B-21
Spark Plug Inspection and Replacement...........................1B-7 Positioning Outboard for Storage............................. 1B-21
Timing Belt Inspection........................................................1B-8 Battery Storage.........................................................1B-22
Changing Engine Oil ......................................................... 1B-8 Storage Lubrication Points........................................1B-22

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-1

Maintenance

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Propeller shaft
Swivel bracket, tilt tube, transom clamp screws, steering cable
Extreme Grease grease fitting 8M0071842
Water intake housing mounting flange and mounting bolts
Driveshaft bearing
Propeller shaft
Swivel bracket, tilt tube, transom clamp screws, steering cable
95 2-4-C with PTFE 92-802859A 1
grease fitting
Driveshaft bearing
Power Trim and Steering
114 Power trim system 92-858074K01
Fluid
120 Corrosion Guard External metal surfaces (except corrosion control anodes) 92-802878 55

Special Tools
Flushing Device 91‑44357Q 2

Attaches to the water intakes; provides a fresh water connection when flushing
the cooling system or operating the engine.

9192

Selecting Accessories for Your Outboard

Genuine Mercury Precision or Quicksilver Accessories have been specifically designed and tested for your outboard. These
accessories are available from Mercury Marine dealers.
IMPORTANT: Check with your dealer before installing accessories. The misuse of approved accessories or the use of
nonapproved accessories can damage the product.
Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or
outboard operating system. Acquire and read the installation, operation and maintenance manuals for all your selected
accessories.

EPA Regulations
All new outboards manufactured by Mercury Marine are certified to the United States Environmental Protection Agency, as
conforming to the requirements of the regulations for the control of air pollution from new outboard motors. This certification is
contingent on certain adjustments being set to factory standards. For this reason, the factory procedure for servicing the
product must be strictly followed and, wherever practicable, returned to the original intent of the design. Maintenance,
replacement, or repair of the emission control devices and systems may be performed by any marine spark ignition
(SI) engine repair establishment or individual.

Page 1B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance

EPA Emissions
Emission Certification Label
An emission certification label, showing emission levels and engine specifications directly related to emissions, is placed on the
engine at time of manufacture.

a EMISSION CONTROL
INFORMATION a- Idle speed
b
THIS ENGINE CONFORMS TO CALIFORNIA AND U.S. EPA
EMISSION REGULATIONS FOR SPARK IGNITION MARINE ENGINES f b- Engine horsepower
REFER TO OWNERS MANUAL FOR REQUIRED MAINTENANCE,
SPECIFICATIONS, AND ADJUSTMENTS
g c- Piston displacement
c IDLE SPEED (in gear): FAMILY:
d- Date of manufacture
hp cc FEL: g/kWh
e- Valve clearance (if applicable)
d TIMING (IN DEGREES): h
SPARK PLUG:
GAP:
f- Family number
i g- Maximum emission output for the engine family
e COLD VALVE
CLEARANCE (mm)
INTAKE:
EXHAUST:
21096
h- Timing specification
i- Recommended spark plug and gap

Owner Responsibility
The owner/operator is required to have routine engine maintenance performed to maintain emission levels within prescribed
certification standards.
The owner/operator is not to modify the engine in any manner that would alter the horsepower or allow emissions levels to
exceed their predetermined factory specifications.

Inspection and Maintenance Schedule

Daily Checks
• Check the engine oil level
• Check the lanyard stop switch
• Inspect the fuel system for leaks
• Inspect the engine tightness on the transom
• Check the steering system for binding
• Check the propeller for damage
• Inspect the hydraulic steering fittings and hoses for leaks or signs of damage, if equipped
• Check the hydraulic steering fluid level, if equipped

After Each Use

• Wash the power package exterior with fresh water
• Flush the outboard cooling system, saltwater or brackish water only

Annually or 100 Hours

• Grease the engine, if applicable
• Change the engine oil and filter, if equipped
• Inspect the thermostat, saltwater or brackish water only
• Add Quickleen to the fuel tank, once per year, per engine
• Apply anti‑seize to the spark plug threads
• Replace the gear lubricant
• Inspect the corrosion control anodes
• Replace all filters on the suction side of the fuel system—dealer item
• Lubricate the driveshaft splines—dealer item
• Lubricate the propeller shaft splines—dealer item
• Check the tightness on all the fasteners—dealer item
• Check the torque of the outboard mounting hardware—dealer item
• Check the battery condition and tightness of the battery cable connection—dealer item

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-3

Maintenance

Three years or 300 Hours

• Replace the spark plugs
• Replace the water pump impeller—dealer item
• Inspect the carbon fiber reeds—dealer item
• Inspect the wire harness connectors—dealer item
• Check the remote control cable adjustment, if applicable—dealer item
• Replace the high‑pressure fuel filter—dealer item
• Replace the accessory drive belt—dealer item
• Check the power trim fluid level—dealer item
• Inspect the engine motor mounts—dealer item

Battery Inspection
The battery should be inspected at periodic intervals to ensure proper engine starting capability.
IMPORTANT: Read the safety and maintenance instructions which accompany your battery.
1. Turn off the engine before servicing the battery.
2. Ensure the battery is secure against movement.
3. Battery cable terminals should be clean, tight, and correctly installed. Positive to positive and negative to negative.
4. Ensure the battery is equipped with a nonconductive shield to prevent accidental shorting of battery terminals.

Submerged Outboard
A submerged outboard will require service within a few hours by an authorized dealer once the outboard is recovered from the
water. This immediate attention by a servicing dealer is necessary once the engine is exposed to the atmosphere to minimize
internal corrosion damage to the engine.

Exterior Care
The outboard is protected with a durable baked enamel finish. Clean and wax often using marine cleaners and waxes. Do not
wax textured areas of cowl.

Flushing the Cooling System

Flush the internal water passages of the outboard with fresh water after each use in salt, polluted, or muddy water. This will
help prevent a buildup of deposits from clogging the internal water passages.
Use a Mercury Precision or Quicksilver accessory (or equivalent) flushing attachment.
IMPORTANT: The engine must be run during flushing in order to open the thermostat and circulate water through the water
passages.

! WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.

1. Remove the propeller. Refer to Propeller Replacement. Install the flushing attachment so the rubber cups fit tightly over
the cooling water intake.

27256

Flushing Device 91‑44357Q 2

Page 1B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
2. Attach a water hose to the flushing attachment. Turn on the water and adjust the flow so water is leaking around the rubber
cups to ensure the engine receives an adequate supply of cooling water.

27259

3. Start the engine and run it at idle speed in neutral shift position.
IMPORTANT: Do not run the engine above idle when flushing.
4. Adjust the water flow (if necessary) so excess water continues leaking out from around the rubber cups to ensure the
engine is receiving an adequate supply of cooling water.

27260

5. Check for a steady stream of water flowing out of the water pump indicator hole. Continue flushing the outboard for 3 to 5
minutes, carefully monitoring water supply at all times.
6. Stop the engine, turn off the water, and remove the flushing attachment. Install the propeller.

Flushing Jet Models

NOTE: Jet models cannot be flushed using a flushing device. Jet models may be flushed by running the outboard in a fresh
water tank.

Top Cowl Removal and Installation

Removal
1. Unlock the rear latch by pulling lever up.

10190

2. Lift rear of cowl and disengage front hook.

10191

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-5

Maintenance

Installation
1. Lower the top cowl over the engine. Bring the front of the cowl down first and engage the front hook, then lower the cowl
into its seated position with the bottom cowl.
2. Apply some downward pressure on the bottom cowl and then lock the cowl in place by pushing in the cowl latch. Ensure
the top cowl is securely fastened by pulling up on the back of the cowl.

Fuel System
! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

Before servicing any part of the fuel system, stop engine and disconnect the battery. Drain the fuel system completely. Use an
approved container to collect and store fuel. Wipe up any spillage immediately. Material used to contain spillage must be
disposed of in an approved receptacle. Any fuel system service must be performed in a well ventilated area. Inspect any
completed service work for sign of fuel leakage.

Fuel Line Inspection

Visually inspect the fuel line and primer bulb for cracks, swelling, leaks, hardness, or other signs of deterioration or damage. If
any of these conditions are found, the fuel line or primer bulb must be replaced.

Fuel Filter (Low Pressure)

Check the fuel filter for water accumulation or sediment. If water is in the fuel, remove the sight bowl and drain the water. If the
filter appears to be contaminated, remove and replace.

Removal
1. Read Fuel System servicing information and Warning, preceding.
2. Pull out the filter assembly from mount. Hold on to the cover to prevent it from turning and remove the sight bowl. Empty
contents into an approved container.
3. Pull out the filter element and replace it if necessary.

a a- Cover
b- Filter element
c- O‑ring seal
b d- Sight bowl

d
9694

Installation
1. Push the filter element into the cover.
2. Place the O‑ring seal into its proper position on the sight bowl and screw the sight bowl hand‑tight into the cover.
3. Push filter assembly back into mount.
IMPORTANT: Visually inspect for fuel leakage from the filter by squeezing the primer bulb until firm, forcing fuel into the
filter.

Fuse Replacement ‑ Electric Start Models

IMPORTANT: Always carry spare SFE 20 amp fuses.
The electric starting circuit is protected from overload by an SFE 20 amp fuse. If the fuse is blown, the electric starter motor will
not operate. Try to locate and correct the cause of the overload. If the cause is not found, the fuse may blow again.

Page 1B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
Open the fuse holder and look at the silver colored band inside the fuse. If band is broken, replace the fuse. Replace fuse with
a new fuse with the same rating.

a - Good fuse
b - Blown fuse

a b

15917

Spark Plug Inspection and Replacement

! WARNING
Damaged spark plug boots may emit sparks that can ignite fuel vapors under the engine cowl, resulting in serious injury or
death from a fire or explosion. To avoid damaging the spark plug boots, do not use any sharp object or metal tool to remove
the spark plug boots.

1. Remove the spark plug leads. Twist the rubber boots slightly and pull off.

26899

2. Remove the spark plugs to inspect. Replace spark plug if electrode is worn or the insulator is rough, cracked, broken,
blistered, or fouled.

26946

3. Set the spark plug gap to specifications.

27848

Spark Plug Gap

Spark plug 0.80–0.90 mm (0.031–0.035 in.)
4. Before installing spark plugs, clean off any dirt on the spark plug seats. Install plugs finger‑tight, and then tighten to the
specified value.

Description Nm lb‑in. lb‑ft

Spark plug 20 – 14

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-7

Maintenance

Timing Belt Inspection

Inspect the timing belt and have it replaced by an authorized dealer if any of the following conditions are found.
• Cracks in the back of the belt or in the base of the belt teeth.
• Excessive wear at the roots of the cogs.
• Rubber portion swollen by oil.
• Belt surfaces roughened.
• Signs of wear on edges or outer surfaces of belt.

9697

Changing Engine Oil

Engine Oil Capacity
Engine oil capacity is approximately 1.8 liter (1.9 quarts).

Oil Changing Procedure

1. Tilt the outboard up to the trailer position.
2. Turn the steering on the outboard so that the drain hole is facing downward. Remove drain plug and drain engine oil into
an appropriate container. Lubricate the seal on the drain plug with oil and install.

15916

Changing Oil Filter

1. Place a rag or towel below the oil filter to absorb any spilled oil.
2. Unscrew old filter by turning the filter to the left.

9735

3. Clean the mounting base. Apply film of clean oil to filter gasket. Do not use grease. Screw new filter on until gasket
contacts base, then tighten 3/4 to 1 turn.

Page 1B-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance

Oil Filling
1. Remove the oil fill cap and add oil to proper operating level.
2. Idle engine for five minutes and check for leaks. Stop engine and check oil level on dipstick. Add oil if necessary.

a - Oil fill cap

a

9737

Checking Power Trim Fluid

1. Tilt the outboard to the full up position and engage the tilt support lock.

9703

2. Remove the fill cap and check the fluid level. The fluid level should be even with the bottom of the fill hole. Add Quicksilver
or Mercury Precision Lubricants Power Trim and Steering Fluid. If not available, use automotive (ATF) automatic
transmission fluid.

9701

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system 92-858074K01
Fluid

Corrosion Control Anode

Your outboard has corrosion control anodes at different locations. An anode helps protect the outboard against galvanic
corrosion by sacrificing its metal to be slowly corroded instead of the outboard metals.
Each anode requires periodic inspection, especially in saltwater which will accelerate the erosion. To maintain this corrosion
protection, always replace the anode before it is completely eroded. Never paint or apply a protective coating on the anode as
this will reduce effectiveness of the anode.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-9

Maintenance
One anode is installed in the engine block. Remove the flange screw at the location shown. Remove the screw securing the
anode. Fasten the anode to the flange screw. Tighten the screw to the specified torque. Install the flange screw with a new
O‑ring. Tighten the flange screw to the specified torque.

a a- Flange screw
b c
d b- O‑ring
c- Anode
d- Screw

57328

Description Nm lb‑in. lb‑ft

Flange screw 6 53 –
Screw 6 53 –

The second anode is the trim tab and the third anode is installed on the transom brackets.

a - Trim tab
b - Transom bracket anode ‑ long
a c - Transom bracket anode ‑ short

10239
10236 10243

b c

Propeller Replacement
! WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.

1. Shift the outboard to neutral (N) position.

F
NEUTRAL F
NEUTRAL
START R
START

26838 10051

IMPORTANT: Refer to Spark Plug Inspection and Replacement for removing spark plug leads.

Page 1B-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
2. Remove the spark plug leads to prevent the engine from starting.

26899

3. Straighten and remove the cotter pin.

4. Place a block of wood between the gearcase and the propeller to hold the propeller and remove the propeller nut.
5. Pull the propeller straight off shaft. If propeller is seized to the shaft and cannot be removed, have the propeller removed by
an authorized dealer.

10075
28351

IMPORTANT: To prevent the propeller hub from corroding and seizing to the propeller shaft (especially in saltwater),
always apply a coat of the recommended lubricant to the entire propeller shaft at the recommended maintenance intervals
and also each time the propeller is removed.
6. Coat the propeller shaft with Extreme Grease or 2‑4‑C with PTFE.

10087

Tube Ref No. Description Where Used Part No.

Extreme Grease Propeller shaft 8M0071842

95 2-4-C with PTFE Propeller shaft 92-802859A 1

7. Install the front thrust hub, propeller, rear thrust hub washer and propeller nut onto the shaft.

a c a- Propeller nut
b
d
b- Rear thrust washer
c- Propeller
d- Front thrust hub

10077

8. Place a block of wood between the gearcase and the propeller and torque the propeller nut to specification.
NOTE: If the propeller nut does not align with the propeller shaft hole after tightening to the specified torque, then tighten
the nut further to align it with the hole.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-11

Maintenance
9. Align the propeller nut with the propeller shaft hole. Insert a new cotter pin in the hole and bend the cotter pin ends.

28353 28351

Description Nm lb‑in. lb‑ft

Propeller nut 25 – 18
10. Install the spark plug leads.

Gearcase Lubrication
When adding or changing gearcase lubricant, visually check for the presence of water in the lubricant. If water is present, it may
have settled to the bottom and will drain out prior to the lubricant, or it may be mixed with the lubricant, giving it a milky colored
appearance. If water is noticed, have the gearcase checked by your dealer. Water in the lubricant may result in premature
bearing failure or, in freezing temperatures, will turn to ice and damage the gearcase.
Examine the drained gearcase lubricant for metal particles. A small amount of metal particles indicates normal gear wear. An
excessive amount of metal filings or larger particles (chips) may indicate abnormal gear wear and should be checked by an
authorized dealer.

Draining Gearcase
1. Place outboard in a vertical operating position.
2. Place drain pan below outboard.
3. Remove vent plug and fill/drain plug and drain lubricant.

a a - Vent plug
b - Fill/drain plug

b
9836

Gearcase Lubricant Capacity

Gearcase lubricant capacity is approximately 350 ml (11.8 fl. oz.).

Gearcase Lubricant Recommendation

Mercury or Quicksilver Premium or High Performance Gear Lubricant.

Checking Lubricant Level and Refilling Gearcase

1. Place outboard in a vertical operating position.
2. Remove vent plug.

Page 1B-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
3. Remove drain plug. Place lubricant tube into the fill hole and add lubricant until it appears at the vent hole.

a a - Vent plug and sealing washer

b - Drain plug and sealing washer

b
9836

IMPORTANT: Replace sealing washers if damaged.

4. Stop adding lubricant. Install the vent plug and sealing washer before removing the lubricant tube.
5. Remove lubricant tube and reinstall cleaned fill/drain plug and sealing washer.

Lubrication Points
1. Lubricate the following with Extreme Grease or 2‑4‑C with PTFE.

Tube Ref No. Description Where Used Part No.

Extreme Grease Propeller shaft 8M0071842

95 2-4-C with PTFE Propeller shaft 92-802859A 1

• Propeller shaft ‑ Refer to Propeller Replacement for removal and installation of the propeller. Coat the entire
propeller shaft with lubricant to prevent the propeller hub from corroding and seizing to the shaft.

10189

2. Lubricate the following with 2‑4‑C with PTFE or Extreme Grease.

Tube Ref No. Description Where Used Part No.

Swivel bracket, tilt tube, transom clamp screws, steering
Extreme Grease 8M0071842
cable grease fitting
Swivel bracket, tilt tube, transom clamp screws, steering
95 2-4-C with PTFE 92-802859A 1
cable grease fitting

• Swivel bracket ‑ Lubricate through fitting.

10169

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-13

Maintenance

• Tilt tube ‑ Lubricate through fittings.

15915

• Lubricate threads on transom clamp screws (if equipped).

15914

• Steering cable grease fitting (if equipped) ‑ Rotate the steering wheel to fully retract the steering cable end into the
outboard tilt tube. Lubricate through fitting.

a a - Fitting
b - Steering cable end
b

59492

! WARNING
Incorrect cable lubrication can cause hydraulic lock, leading to serious injury or death from loss of boat control. Completely
retract the end of the steering cable before applying lubricant.
3. Lubricate the following with lightweight oil.
• Steering link rod pivot points ‑ Lubricate pivot points.

59491

Jet Maintenance
Worn/Dull Impeller
The intake of gravel through the pump can round off and wear the leading edges of the impeller. Some conditions that could be
experienced from a worn/dull impeller are as follows:
• Noticeable performance loss, especially on acceleration
• Difficulty getting the boat on plane

Page 1B-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
• An increase in engine RPM at wide‑open throttle
IMPORTANT: Do not sharpen or alter the top side lifting angle.
Check the impeller blades occasionally for damage. Use a flat file to sharpen the leading edges. Sharpen to a 0.8 mm (1/32 in.)
radius by removing material from bottom side only.

a - Leading edge
b b - Top side lifting angle

a 29079

Impeller Clearance Adjustment

The impeller should be adjusted so there is approximately 0.76 mm (0.03 in.) clearance between the impeller edge and liner.
Operating the jet drive in waters that contain sand and gravel can cause wear to the impeller blades, and the clearance will
start to exceed 0.76 mm (0.03 in.).
As the blades wear, shims located in the stack outside of the impeller can be transferred behind the impeller. This will move the
impeller further down into the tapered liner to reduce the clearance.

a - Shims
b - Clearance between impeller edge and liner

a
b 29080

Check the impeller clearance by sliding a feeler gauge through the intake grate and measure the clearance between the
impeller edge and liner. If adjustment is required, refer to Impeller Removal and Installation.

Impeller Removal and Installation

! WARNING
Rotating the driveshaft may cause the engine to crank over and start. To prevent this type of accidental engine starting and
possible serious injury caused from being struck by a rotating impeller, always turn the ignition key or lanyard stop switch to
the "OFF" position and remove the spark plug leads from the spark plugs while servicing the impeller.

1. Shift the outboard to the neutral position.

R
N
F

24835

2. Position the key switch or lanyard stop switch to the OFF position.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-15

Maintenance
3. Remove the spark plug leads to prevent the engine from starting.

26899

4. Remove the six screws securing the water intake housing, and remove the water intake housing.

29081

5. Straighten the bent tabs on the impeller nut retainer and remove the impeller nut.

a - Tabs
b - Impeller nut

a
b 29082

6. Pull the impeller straight off the shaft. If the impeller is tight, use a hammer and a block of wood to rotate the impeller
clockwise on the shaft until the keyway is directly above the flat on the shaft. This will free the jammed key and allow
removal.

Installation
1. Lubricate the driveshaft, shear key, and impeller bore.
2. Place the plastic sleeve inside the impeller and install impeller, shear key, shims, nut retainer, and impeller nut.

a- Plastic sleeve
b- Impeller
c- Shear key
d- Shims
e- Nut retainer
f- Impeller nut

c
d
e
f 29083
3. Turn the nut tight on the shaft to remove any play between the impeller and shaft. If the tabs on the retainer do not line up
with the flats on the nut, remove the nut and turn the retainer over and tighten the nut again.

Page 1B-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance

4. Temporarily install the water intake housing in order to check for impeller clearance. The clearance between the impeller
and liner should be 0.76 mm (0.03 in.). Shim washers can be transferred to either side of the impeller to raise or lower the
impeller to the correct clearance setting. The water intake housing can be shifted sideways a small amount in order to
center the liner.

a - Shims
b - Clearance between impeller edge and liner

a
b 29080

5. After setting the impeller height, tighten the impeller nut snug with a wrench. Secure impeller nut by bending tabs against
the flats on the impeller nut.

a - Tabs
b - Impeller nut

a
b 29082

NOTE: If the outboard is used in saltwater, apply Extreme Grease around the entire mounting flange on the water intake
housing and also to the threads on the six mounting bolts.

Tube Ref No. Description Where Used Part No.

Extreme Grease Water intake housing mounting flange and mounting bolts 8M0071842
6. Install the water intake housing with six bolts. Check clearance around the impeller to ensure the water intake housing is
centered and not rubbing against the liner. Tighten the mounting bolts to the specified torque.

29081

Description Nm lb‑in. lb‑ft

Water intake housing mounting bolts 13 120 –

Shift Link Rod Adjustment

! WARNING
Pressurized water hitting the reverse gate may cause it to engage, causing sudden and unexpected slowing of the boat. This
can cause serious injury or death from occupants being thrown within or out of the boat. Adjust the shift link rod to lock the
reverse gate, preventing it from interfering with water flow.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-17

Maintenance

Checking Shift Link Rod Adjustment

Check the shift link rod adjustment in forward shift position. The correct adjustment will position the shift cam far enough on the
roller in order to lock the reverse gate into forward position. The reverse gate should not be able to be forced up towards
neutral. Pull on the reverse gate by hand to verify.

a
a- Shift link rod
b- Shift cam
b c- Roller
d- Reverse gate

c
29084

d
Adjusting Shift Link Rod
1. Place the shift handle into full forward shift position.
2. Adjust the length of the shift link rod so the roller is at the full end of travel (bottom) in the shift cam when the shift handle is
in forward.

Corrosion Control Anode

Your outboard has corrosion control anodes at different locations. An anode helps protect the outboard against galvanic
corrosion by sacrificing its metal to be slowly corroded instead of the outboard metals.
Each anode requires periodic inspection, especially in saltwater which will accelerate the erosion. To maintain this corrosion
protection, always replace the anode before it is completely eroded. Never paint or apply a protective coating on the anode as
this will reduce effectiveness of the anode.
One anode is installed in the engine block. Remove the flange screw at the location shown. Remove the screw securing the
anode. Fasten the anode to the flange screw. Tighten the screw to the specified torque. Install the flange screw with a new
O‑ring. Tighten the flange screw to the specified torque.

a a- Flange screw
b c
d b- O‑ring
c- Anode
d- Screw

57328

Description Nm lb‑in. lb‑ft

Flange screw 6 53 –
Screw 6 53 –

Page 1B-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
The second anode is on the water intake housing and the third anode is installed on the transom brackets.

a - Water intake housing anode

b - Transom bracket anode

10239
a 24838

Lubrication Points
1. Lubricate the following with Extreme Grease or 2‑4‑C with PTFE.

Tube Ref No. Description Where Used Part No.

Extreme Grease Driveshaft bearing 8M0071842

95 2-4-C with PTFE Driveshaft bearing 92-802859A 1

• Driveshaft bearing
IMPORTANT: It is important not to use a general all‑purpose grease for this bearing. The lubricant recommended is a
water‑resistant grease of the proper consistency for this application. If a substitute is used, be sure that it is
water‑resistant and of the same consistency.
i. Pull the vent hose off of the grease fitting.
ii. Pump in grease through the grease fitting, using the grease gun provided, until excess grease starts to exit the
vent hose.
iii. Reconnect the vent hose onto the grease fitting after greasing.

a - Grease fitting
b - Vent hose

a b

29101

NOTE: After 30 hours of operation, pump in extra grease to purge out any moisture. Visually inspecting the purged
grease at this time will give an indication of conditions inside the bearing housing. A gradual increase in moisture
content, indicates seal wear. If the grease begins to turn dark or dirty gray, the driveshaft bearing and seals should be
inspected and replaced if necessary. Some discoloration of the grease is normal during the break‑in period on a new
set of seals.
2. Lubricate the following with 2‑4‑C with PTFE or Extreme Grease.

Tube Ref No. Description Where Used Part No.

Swivel bracket, tilt tube, transom clamp screws, steering
Extreme Grease 8M0071842
cable grease fitting
Swivel bracket, tilt tube, transom clamp screws, steering
95 2-4-C with PTFE 92-802859A 1
cable grease fitting

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-19

Maintenance
• Swivel bracket ‑ Lubricate through fitting.

24839

• Tilt tube ‑ Lubricate through fittings.

15915

• Lubricate the threads on the transom clamp screws (if equipped).

15914

• Steering cable grease fitting (if equipped) ‑ Rotate the steering wheel to fully retract the steering cable end into the
outboard tilt tube. Lubricate through fitting.

a a - Fitting
b - Steering cable end
b

59492

! WARNING
Incorrect cable lubrication can cause hydraulic lock, leading to serious injury or death from loss of boat control. Completely
retract the end of the steering cable before applying lubricant.
3. Lubricate the following with lightweight oil.

Page 1B-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Maintenance
• Steering link rod pivot points ‑ Lubricate the pivot points.

59491

Storage Preparation
The major consideration in preparing your outboard for storage is to protect it from rust, corrosion, and damage caused by
freezing of trapped water.
The following storage procedures should be followed to prepare your outboard for out of season storage or prolonged storage
(two months or longer).

NOTICE
Without sufficient cooling water, the engine, the water pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during operation.

Fuel System
IMPORTANT: Gasoline containing alcohol (ethanol or methanol) can cause a formation of acid during storage and can damage
the fuel system. If the gasoline being used contains alcohol, it is advisable to drain as much of the remaining gasoline as
possible from the fuel tank, remote fuel line, and engine fuel system.
Fill the fuel tank and engine fuel system with treated (stabilized) fuel to help prevent formation of varnish and gum. Proceed
with the following instructions.
• Portable fuel tank ‑ Pour the required amount of gasoline stabilizer (follow instructions on container) into fuel tank. Tip fuel
tank back and forth to mix stabilizer with the fuel.
• Permanently installed fuel tank ‑ Pour the required amount of gasoline stabilizer (follow instructions on container) into a
separate container and mix with approximately 1 liter (1 U.S. quart) of gasoline. Pour this mixture into fuel tank.
• Place the outboard in water or connect flushing attachment for circulating cooling water. Run the engine for ten minutes to
fill the engine fuel system.

Flushing Device 91‑44357Q 2

Protecting External Outboard Components

• Lubricate all outboard components listed in the Inspection and Maintenance Schedule, preceding.
• Touch‑up any paint nicks.
• Spray Quicksilver or Mercury Precision Lubricants Corrosion Guard on external metal surfaces (except corrosion control
anodes).

Tube Ref No. Description Where Used Part No.

120 Corrosion Guard External metal surfaces (except corrosion control anodes) 92-802878 55

Protecting Internal Engine Components

• Remove the spark plugs and add approximately 30 ml (1 oz.) of engine oil or inject a five second spray of storage seal
inside of each cylinder.
• Rotate the flywheel manually several times to distribute the oil in the cylinders. Install spark plugs.
• Change the engine oil.

Gearcase
• Drain and refill the gearcase lubricant (refer to Gearcase Lubrication).

Positioning Outboard for Storage

Store outboard in an upright (vertical) position to allow water to drain out of the outboard.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1B-21

Maintenance

NOTICE
Storing the outboard in a tilted position can damage the outboard. Water trapped in the cooling passages or rain water
collected in the propeller exhaust outlet in the gearcase can freeze. Store the outboard in the full down position.

Battery Storage
• Follow the battery manufacturer's instructions for storage and charging.
• Remove the battery from the boat and check water level. Charge if necessary.
• Store the battery in a cool, dry place.
• Periodically check the water level and charge the battery during storage.

Storage Lubrication Points

Refer to Lubrication Points in this section.

Page 1B-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 General Information

Important Information
1
Section 1C - General Information C
Table of Contents
Manual Start Component Identification..............................1C-3 Engine Submerged While Running (Special
25/30 4‑Stroke EFI Manual Start Front View..............1C-3 Instructions).......................................................... 1C-12
25/30 4‑Stroke EFI Manual Start Starboard View...... 1C-4 Saltwater Submersion (Special Instructions)............1C-13
25/30 4‑Stroke EFI Manual Start Port View................1C-5 Fresh Water Submersion (Special Instructions)....... 1C-13
25/30 4‑Stroke EFI Manual Start Rear View.............. 1C-6 Fuel Requirements.......................................................... 1C-13
Electric Start Component Idenitication...............................1C-7 Fuel Ratings............................................................. 1C-13
25/30 4‑Stroke EFI Electric Start Front View..............1C-7 Using Reformulated (Oxygenated) Gasoline (USA
25/30 4‑Stroke EFI Electric Start Starboard View...... 1C-8 Only)..................................................................... 1C-13
25/30 4‑Stroke EFI Electric Start Port View................1C-9 Gasoline Containing Alcohol.................................... 1C-13
25/30 4‑Stroke EFI Electric Start Rear View............ 1C-10 Compression Check........................................................ 1C-14
Conditions Affecting Performance................................... 1C-10 Cylinder Leakage Testing................................................ 1C-14
Weather.................................................................... 1C-10 Analysis.................................................................... 1C-15
Weight Distribution (Passengers and Gear) Inside the Painting Procedures........................................................ 1C-15
Boat.......................................................................1C-11 Propellers................................................................. 1C-15
Bottom of Boat .........................................................1C-11 Gear Housing........................................................... 1C-15
Water Absorption......................................................1C-11 Decal Removal................................................................ 1C-16
Cavitation..................................................................1C-11 Decal Application............................................................. 1C-16
Elevation and Climate...............................................1C-12 Application Tips........................................................ 1C-16
Detonation................................................................ 1C-12 Applying the Decal....................................................1C-16
Propeller Selection................................................... 1C-12 Entrapped Air Removal............................................ 1C-17
Following Complete Submersion..................................... 1C-12 Final Decal Squeegee.............................................. 1C-17

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General Information

Special Tools
Cylinder Leakage Tester Snap‑On EEPV309A

Aids in checking cylinder leakdown.

11604

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 General Information

Manual Start Component Identification

25/30 4‑Stroke EFI Manual Start Front View

i j
k
h
l
g

e m

d
n
o
c p

9478

a- Steering friction adjuster

b- Low oil pressure lamp
c- Cable grommet
d- Intake manifold plenum
e- Throttle body
f- Throttle Position Sensor (TPS)
g- Warning horn
h- Recoil handle
i- Recoil interlock cable
j- Air vent assembly
k- Manifold Air Temperature (MAT) sensor
l- Silencer for Idle Air Control (IAC)
m- Vapor Separator Tank (VST)
n- Fuel line connector
o- Lanyard Switch
p- Throttle friction adjuster

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General Information

25/30 4‑Stroke EFI Manual Start Starboard View

f
g

h
e

d
i

c
j
b
k

a
9483

a- Water pump indicator

b- Fuel rail
c- Stator voltage regulator connector
d- Schrader valve
e- Stator ignition/fuel charge connector
f- Recoil interlock
g- Timing window
h- Manifold Absolute Pressure (MAP) sensor
i- Intake manifold plenum
j- Electronic Control Module (ECM)
k- Oil level dip stick
l- Throttle only button

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 General Information

25/30 4‑Stroke EFI Manual Start Port View

e
f
g
h
d
c

9489

a- Fuel line connector

b- Silencer for Idle Air Control (IAC)
c- Vapor Separator Tank (VST)
d- Recoil handle
e- Air vent assembly
f- Fuel cooler
g- Water temperature sensor
h- Ignition Coil
i- Fuel filter
j- Oil filter
k- Rubber plug (optional tilt switch)

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General Information

25/30 4‑Stroke EFI Manual Start Rear View

a- Cowl latch
e b- Oil fill cap
c- Fuel cooler
d d- Air vent assembly
f e- Recoil Interlock cable
f- Engine lift bracket
g- Schrader valve
h- Fuel rail
g
i- Oil level dip stick

b i

21688

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 General Information

Electric Start Component Idenitication

25/30 4‑Stroke EFI Electric Start Front View

g l
j k
i

m
e

n
d
c

p
b

q
a 9592

a- Battery cables
b- Cable grommet
c- Intake manifold plenum
d- Throttle body
e- Throttle Position Sensor (TPS)
f- Voltage regulator battery charging lead connector
g- Recoil interlock cable
h- Recoil handle
i- Trim down solenoid
j- Trim up solenoid
k- Starter solenoid
l- Air vent assembly
m- Silencer for Idle Air Control (IAC)
n- Vapor Separator Tank (VST)
o- Low oil pressure lamp
p- Fuel line connector
q- Rubber plug

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General Information

25/30 4‑Stroke EFI Electric Start Starboard View

i k
j l
h
g
f
m
e
d n

c
b o

9595

a- Water pump indicator

b- Cowl latch
c- Fuel rail
d- Crankcase ventilation hose
e- Schrader valve
f- Manifold
g- Stator ignition/fuel charge connector
h- 14 pin engine harness connector
i- Recoil interlock
j- Fuse holder
k- Voltage regulator rectifier connector
l- Voltage regulator battery charging lead connector
m- Recoil handle
n- Manifold Air Pressure (MAP) sensor
o- Intake manifold plenum
p- Voltage regulator
q- ECM
r- Oil level dip stick

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 General Information

25/30 4‑Stroke EFI Electric Start Port View

f
e g
h

d i

j
c

b k

l
a

9604

a- Fuel line connector

b- Starter motor
c- Silencer for Idle Air Control (IAC)
d- Recoil handle
e- Vapor Separator Tank (VST)
f- Air vent assembly
g- Fuel cooler
h- Water temperature sensor
i- Power tilt switch connector
j- Ignition coils
k- Fuel filter
l- Oil filter
m- Power tilt switch

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General Information

25/30 4‑Stroke EFI Electric Start Rear View

e
f

d
g

c h

i
b

21617

a- Cowl latch
b- Oil fill cap
c- Fuel cooler
d- Air vent assembly
e- Engine lift bracket
f- Recoil interlock cable
g- 14 pin engine harness connector
h- Schrader valve
i- Fuel rail

Conditions Affecting Performance

Weather
It is a known fact that weather conditions exert a profound effect on the power output of internal combustion engines.
Established horsepower ratings refer to the power the engine will produce at its rated RPM under a specific combination of
weather conditions.

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Corporations internationally have settled on adoption of International Standards Organization (ISO) engine test standards, as
set forth in ISO 3046 standardizing the computation of horsepower from data obtained on the dynamometer. All values are
corrected to the power the engine will produce at sea level, at 30% relative humidity, at 25 °C (77 °F) temperature, and a
barometric pressure of 29.61 inches of mercury.
Summer conditions of high temperature, low barometric pressure, and high humidity all combine to reduce the engine power.
This, in turn, is reflected in decreased boat speeds as much as 3 to 5 km/h (2 to 3 MPH) in some cases. Nothing will regain this
speed for the boater but cooler, dry weather.
Pointing out the consequences of weather effects, an engine running on a hot, humid day may encounter a loss of as much as
14% of the horsepower it would produce on a dry, brisk day. The horsepower that any internal combustion engine produces,
depends upon the density of the air that it consumes. The density of air is dependent upon the ambient air temperature, the
barometric pressure, and the humidity (water vapor) content.
Accompanying the effects of weather inspired loss of power is a second, but more subtle loss. Consider a boat rigged during
cooler, less humid weather with a propeller that allowed the engine to turn within its recommended RPM range at full throttle.
Higher temperatures with high humidity weather will consequently decrease the available horsepower. The propeller, in effect,
is too large for the atmospheric conditions and the engine operates at less than its recommended RPM.
The engine‑rated horsepower is a direct relation to the engine's RPM. An engine with too large of a propeller will have a further
loss of horsepower and subsequent decrease in boat speed. This secondary loss of RPM and boat speed can be regained by
switching to a smaller pitch propeller that allows the engine to run at recommended RPM.
For boaters to realize optimum engine performance under changing weather conditions, it is essential the engine has the
proper propeller to allow it to operate at, or near, the top end of the recommended maximum RPM range at wide‑open throttle
with a normal boat load. Not only does this allow the engine to develop full power, but equally important, the engine will be
operating in an RPM range that discourages damaging detonation. This enhances overall reliability and durability of the engine.

Weight Distribution (Passengers and Gear) Inside the Boat

Shifting weight to rear (stern):
• Generally increases speed and engine RPM
• Causes bow to bounce in choppy water
• Increases danger of following wave splashing into the boat when coming off plane
• At extremes, can cause the boat to porpoise
Shifting weight to front (bow):
• Improves ease of planing
• Improves rough water ride
• At extremes, can cause the boat to veer back and forth (bow steer)

Bottom of Boat
For maximum speed, a boat bottom should be nearly a flat plane where it contacts the water and particularly straight and
smooth in fore and aft direction.
• Hook: Exists when bottom is concave in fore and aft direction when viewed from the side. When boat is planing, hook
causes more lift on bottom near transom and allows bow to drop, thus greatly increasing wetted surface and reducing boat
speed. Hook frequently is caused by supporting boat too far ahead of transom while hauling on a trailer or during storage.
• Rocker: The reverse of hook and much less common. Rocker exists if bottom is convex in fore and aft direction when
viewed from the side, and boat has strong tendency to porpoise.
• Surface roughness: Moss, barnacles, etc., on boat or corrosion of outboard's gear housing increase skin friction and
cause speed loss. Clean surfaces when necessary.

Water Absorption
It is imperative that all through‑the‑hull fasteners be coated with a quality marine sealer at time of installation. Water intrusion
into the transom core and/or inner hull will result in additional boat weight (reduced boat performance), hull decay, and eventual
structural failure.

Cavitation
Cavitation occurs when water flow cannot follow the contour of a fast‑moving underwater object, such as a gear housing or a
propeller. Cavitation increases propeller speed while reducing boat speed. Cavitation can seriously erode the surface of the
gear housing or the propeller. Common causes of cavitation are:
• Weeds or other debris snagged on the propeller
• Bent propeller blade
• Raised burrs or sharp edges on the propeller

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Elevation and Climate

Elevation and climate changes will affect the performance of your power package. Loss of performance can be caused by:
• Higher elevations
• Higher temperatures
• Low barometric pressures
• High humidity
For you to have optimum engine performance under changing weather conditions, it is essential that the engine be propped to
allow the engine to operate at or near the top end of the specified maximum RPM range with a normal boat load during your
normal boating weather conditions.
In most cases, recommended RPM can be achieved by changing to a lower pitch propeller.

Detonation
Detonation in a 4‑cycle engine resembles the pinging heard in an automobile engine. It can be otherwise described as a tin‑like
rattling or plinking sound.
Detonation is the explosion of the unburned fuel/air charge after the spark plug has fired. Detonation creates severe shock
waves in the engine. These shock waves often find or create a weakness: the dome of a piston, cylinder head or gasket, piston
rings or piston ring lands, piston pin, and roller bearings.
A few of the most common causes of detonation in a marine 4‑cycle application are as follows:
• Over‑advanced ignition timing
• Use of low octane gasoline
• Propeller pitch too high: engine RPM below recommended maximum range
• Lean fuel mixture at, or near, wide‑open throttle
• Spark plugs: heat range too hot, incorrect reach, cross‑firing
• Deteriorated or inadequate engine cooling system
• Combustion chamber deposits: result in higher compression ratio
Detonation usually can be prevented if:
• The engine is correctly set up
• Regular maintenance is scheduled

Propeller Selection
IMPORTANT: The engines covered in this manual are equipped with an RPM rev‑limiter that is set to an upper RPM limit. This
limit, which is slightly above the normal operating range of the engine, helps prevent damage from excessive engine RPM.
Once the RPM returns to the recommended operating RPM range, normal engine operation resumes.
The boat manufacturer and the selling dealer are responsible for equipping the power package with the correct propeller. Refer
to Mercury Marine's web page https://www.mercurymarine.com/en/us/propellers/selector/#/step‑one.
Select a propeller that will allow the engine power package to operate at or near the top end of the recommended WOT
operating RPM range with a normal load.
If full‑throttle operation is below the recommended range, the propeller must be changed to prevent loss of performance and
possible engine damage. On the other hand, operating an engine above the recommended operating RPM range will cause
higher than normal wear and damage.
After initial propeller selection, the following common problems may require that the propeller be changed to a lower pitch.
• Warmer weather and greater humidity cause a loss of RPM.
• Operating in a higher elevation causes a loss of RPM.
• Operating with a dirty boat bottom causes a loss of RPM.
• Operating with increased load (additional passengers, pulling skiers) causes a loss of RPM.
For better acceleration, such as is needed for waterskiing, use the next lower pitch propeller. When not pulling skiers, do not
operate at full throttle when using the lower pitch propeller.

Following Complete Submersion

Engine Submerged While Running (Special Instructions)
When an engine is submerged while running, the possibility of internal engine damage is greatly increased. After the engine is
recovered, remove the spark plugs. If the engine fails to turn over freely when turning the flywheel, the possibility of internal
damage (bent connecting rod and/or bent crankshaft) exists. The powerhead must be disassembled for inspection.

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Saltwater Submersion (Special Instructions)

Due to the corrosive effect of saltwater on internal engine components, complete disassembly of the engine is necessary
before any attempt is made to start the engine.

Fresh Water Submersion (Special Instructions)

1. Recover the engine as quickly as possible.
2. Remove cowling.
3. Flush exterior of outboard with fresh water to remove mud, weeds, etc. Do not attempt to start engine if sand has entered
powerhead. Disassemble powerhead, if necessary, to clean components.
4. Remove spark plugs and get as much water as possible out of powerhead. Most of the water can be eliminated with
portable engines by placing the engine in a horizontal position (with spark plug holes down) and rotating flywheel.
5. Change the engine oil. Run the outboard for a short time and check for the presence of water in the oil. If water is present,
the oil will appear milky. Drain and replace the oil as previously mentioned.
6. Pour alcohol into carburetor throat. Alcohol will absorb water. Again rotate flywheel.
7. Turn engine over and pour alcohol into spark plug openings and rotate flywheel.
8. When possible, with the spark plug openings facing down, rotate flywheel while pouring engine oil into throat of carburetor.
9. Again turn engine over and pour approximately one teaspoon of engine oil into each spark plug opening. Rotate flywheel to
distribute oil in cylinders.
10. Remove and clean carburetor and fuel pump assembly.
11. Dry all wiring and electrical components using compressed air.
12. Disassemble the engine starter motor and dry all the internal parts with compressed air. Be careful not to lose the brush
springs.
13. Reinstall spark plugs, carburetor, and fuel pump.
14. Attempt to start engine, using a fresh fuel source. If engine starts, it should be run for at least one hour to eliminate any
water in engine.
15. If engine fails to start, determine if the cause is fuel, electrical, or mechanical. The engine should be run within 2 hours after
recovery from the water, or serious internal damage will occur. If unable to start engine within 2 hours of recovery,
disassemble the engine and clean all parts. Apply oil as soon as possible.

Fuel Requirements
IMPORTANT: Use of improper gasoline can damage your engine. Engine damage resulting from the use of improper
gasoline is considered misuse of the engine and will not be covered under the limited warranty.

Fuel Ratings
Mercury outboard engines will operate satisfactorily with any major brand of unleaded gasoline that meets the following
specifications:
USA and Canada ‑ A posted pump octane rating of 87 (R+M)/2, minimum, for most models. Premium gasoline 91 (R+M)/2
octane is also acceptable for most models. Do not use leaded gasoline.
Outside USA and Canada ‑ A posted pump octane rating of 91 RON, minimum, for most models. Premium gasoline (95 RON)
is also acceptable for all models. Do not use leaded gasoline.

Using Reformulated (Oxygenated) Gasoline (USA Only)

Reformulated gasoline is required in certain areas of the USA and is acceptable for use in your Mercury Marine engine. The
only oxygenate currently in use in the USA is alcohol (ethanol, methanol, or butanol).

Gasoline Containing Alcohol

Bu16 Butanol Fuel Blends
Fuel blends of up to 16.1% butanol (Bu16) that meet the published Mercury Marine fuel rating requirements are an acceptable
substitute for unleaded gasoline. Contact your boat manufacturer for specific recommendations on your boat's fuel system
components (fuel tanks, fuel lines, and fittings).

Methanol and Ethanol Fuel Blends

IMPORTANT: The fuel system components on your Mercury Marine engine will withstand up to 10% alcohol (methanol or
ethanol) content in the gasoline. Your boat's fuel system may not be capable of withstanding the same percentage of alcohol.
Contact your boat manufacturer for specific recommendations on your boat's fuel system components (fuel tanks, fuel lines,
and fittings).
Be aware that gasoline containing methanol or ethanol may cause increased:

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General Information

• Corrosion of metal parts

• Deterioration of rubber or plastic parts
• Fuel permeation through the rubber fuel lines
• Likelihood of phase separation (water and alcohol separating from the gasoline in the fuel tank)

! WARNING
Fuel leakage is a fire or explosion hazard, which can cause serious injury or death. Periodically inspect all fuel system
components for leaks, softening, hardening, swelling, or corrosion, particularly after storage. Any sign of leakage or
deterioration requires replacement before further engine operation.

IMPORTANT: If you use gasoline that contains or might contain methanol or ethanol, you must increase the frequency of
inspection for leaks and abnormalities.
IMPORTANT: When operating a Mercury Marine engine on gasoline containing methanol or ethanol, do not store the gasoline
in the fuel tank for long periods. Cars normally consume these blended fuels before they can absorb enough moisture to cause
trouble; boats often sit idle long enough for phase separation to take place. Internal corrosion may occur during storage if
alcohol has washed protective oil films from internal components.

Compression Check
1. Remove spark plugs.
2. Install compression gauge in spark plug hole.
3. Hold throttle plate at WOT.
4. Pull on the recoil rope or crank the engine over until the compression reading peaks on the gauge. Record the reading.
5. Check and record compression of each cylinder. The highest and lowest reading recorded should not differ by more than
15%. A reading below 827.4 kPa (120 psi) might indicate a total engine wear problem. The following chart, is not a
representation of compression values specific to the engine that is actually tested. It is only an example.

Compression Test Differences

Condition Maximum Reading Minimum Reading
Good 1241 kPa (180 psi) 1062 kPa (154 psi)
Bad 1172 kPa (170 psi) 972.2 kPa (141 psi)
6. To find the maximum allowable minimum compression reading difference, use this formula; highest compression reading x
0.85 = the lowest allowable difference. 1241 kPa x 0.85 = 1054.85 kPa (180 x 0.85 = 153 psi).
7. Compression check is important because an engine with low or uneven compression cannot be tuned successfully to give
peak performance. It is essential, therefore, that improper compression be corrected before proceeding with an engine
tune‑up.
8. Cylinder scoring: If powerhead shows any indication of overheating, such as discolored or scorched paint, visually inspect
cylinders for scoring or other damage as outlined in Section 4 ‑ Powerhead.

Cylinder Leakage Testing

Engine Firing Order
Cylinder sequence 1‑3‑2

NOTE: Cylinder leakage testing, along with compression testing, can help the mechanic pinpoint the source of a mechanical
failure by gauging the amount of leakage in an engine cylinder. Refer to the manufacturer tester instructions for proper testing
procedures.
NOTE: Spark plug hole is a 14 mm diameter. Use Snap‑On Tool MT26J‑200 adapter (or equivalent) with valve core removed.

Cylinder Leakage Tester Snap‑On EEPV309A

1. Remove the spark plugs.

2. Rotate the engine clockwise until resistance is felt.
3. Continue to rotate flywheel so the timing marks on the flywheel and cylinder block are in alignment. This will be the
compression stroke for cylinder #1.
4. Remove the spark plug from #1 cylinder.
5. Complete the cylinder leak down test on the #1 spark plug hole. Refer to the manufactures tester instructions for proper
testing procedures.
6. After testing cylinder #1, install a dial indicator on the next firing order sequence cylinder.

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 General Information
7. Rotate the flywheel so the piston is at TDC.
8. Complete the cylinder leak down test.
9. Proceed with the succeeding firing order cylinder TDC and complete the cylinder leak down test.
10. Complete the procedure in sequence on the remain cylinders.

Analysis
Due to standard engine tolerances and engine wear, no cylinder will maintain a 0% of leakage. It is important only that cylinders
have somewhat consistent reading between them. Differences of 15 to 30% indicate excessive leakage. Larger engines tend to
have a larger percentage of cylinder leakage than smaller engines.
If excessive leakage is present, first check that the piston is at top dead center of its compression stroke. Leakage will naturally
occur if the exhaust or intake valve is open.
To determine the cause of high percentage leaks, you must locate where the air is escaping from. Listen for air escaping
through the intake, adjacent spark plug holes, exhaust pipe, and crankcase oil fill plug. Use the following table to aid in locating
the source of cylinder leakage.

Air Escaping From Possible Location

Air induction Intake valve
Exhaust system Exhaust valve
Oil fill plug Piston/rings
Adjacent cylinder Head gasket

Painting Procedures
! WARNING
Continuous exposure to airborne particles such as chemical vapors, dust, or spray can cause serious injury or death. Ensure
that the work area is properly ventilated and wear protective eyeware, clothing, and respirators.

Propellers
1. Sand the entire area to be painted with 3M 120 Regalite Polycut or coarse Scotch‑Brite disc or belts.
2. Feather edges of all broken paint edges. Try not to sand through the primer.
3. Clean the surface to be painted using PPG Industries DX330 Wax and Grease Remover or equivalent (Xylene or M.E.K.).
4. If bare metal has been exposed, use Mercury/Quicksilver Light Gray Primer.
5. Allow a minimum of one hour dry time and no more than one week before applying the finish coat.
6. Apply the finish coat using Mercury/Quicksilver EDP Propeller Black.

Gear Housing
The following procedures should be used in refinishing gear housings. This procedure will provide the most durable paint
system available in the field. The materials recommended are of high quality and approximate marine requirements. The
following procedure will provide a repaint job that compares with a properly applied factory paint finish. It is recommended the
listed materials be purchased from a local Ditzler Automotive Finish Supply Outlet. The minimum package quantity of each
material shown following is sufficient to refinish several gear housings.
1. Wash the gear housing with a muriatic acid base cleaner to remove any type of marine growth, and rinse with water.
2. Wash the gear housing with soap and water. Rinse with clean water.
3. Sand blistered area with 3M 180 grit sandpaper or P180 Gold Film Disc to remove paint blisters only. Feather edge all
broken paint edges.
4. Clean gear housing thoroughly with DX‑330 Wax and Grease Remover.
5. Spot repair surfaces where bare metal is exposed with DX‑503 Alodine Treatment.
IMPORTANT: Do not use aerosol spray paints as the paint will not properly adhere to the surface, nor will the coating be
sufficiently thick to resist future paint blistering.
6. Mix Epoxy Chromate Primer DP‑90LF with equal part catalyst DP‑402LF per the manufacturer's instructions. Allow proper
induction period for permeation of the epoxy primer and catalyst.
7. Allow a minimum of one hour drying time and no more than one week before the top coat application.
8. Use Ditzler Urethane DU9300 for Mercury Black, DU34334 for Mariner Grey, DU35466 for Force Charcoal, DU33414M for
Sea Ray White, and DFHS 37372H for Verado Silver. Catalyze all five colors with Ditzler DU5 catalyst mixed 1:1 ratio.
Reduce with solvents per Ditzler label.

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General Information

! WARNING
Continuous exposure to airborne particles such as chemical vapors, dust, or spray can cause serious injury or death. Ensure
that the work area is properly ventilated and wear protective eyeware, clothing, and respirators.

NOTE: Apply one half to one mil even film thickness with a spray gun. Allow the paint to flash off for five minutes before
applying the second even coat of one half to one mil film thickness. Urethane paint will dry to the touch in a matter of
hours, but will remain sensitive to scratches and abrasions for a few days.
9. The type of spray gun used will determine the proper reduction ratio of the paint.
IMPORTANT: Do not paint the sacrificial anode.
10. Cut out a cardboard plug for trim tab pocket to keep paint off of mating surface to maintain good continuity circuitry
between trim tab and gear housing.

Decal Removal
1. Mark decal location before removal to assure proper alignment of new decal.
2. Carefully soften decal and decal adhesive with a heat gun or heat blower while removing old decal.
3. Clean decal contact area with a 1:1 mixture of isopropyl alcohol and water.
4. Thoroughly dry decal contact area and check for a completely cleaned surface.

Decal Application
Application Tips
1. Ensure that the surrounding work area and the surface are properly cleaned to avoid contamination.
2. Ensure that the surface and the ambient air temperature is within the specified range.
3. Ensure that your hands are clean and dry.
4. Ensure that the paper liner on the decal does not become wet. A wet paper liner is very difficult to remove.
5. Use the recommended plastic applicator. The applicator should be new and must not be damaged.
a. If the decal has a premask, use the squeegee only.
b. If the decal does not have a premask, use a low friction sleeve or felt squeegee to prevent scratching or damaging
the decal and cowl.
6. Use firm pressure on the squeegee with overlapping strokes.
7. Remove the premask and application tape at a 180° angle to the decal.
8. Puncture the air bubbles with an air release tool or straight pin. Do not use a knife or razor blade.
9. Immediately squeegee the entire decal after removing the premask tape.

Applying the Decal

1. Ensure that your hands are clean and dry.
2. Remove the center paper liner strip from decal if applicable.
3. Align the decal according to the reference placement drawing and apply light pressure on the center strip location.

50526

4. Align the decal and secure one side of the decal with your hand.
5. Lightly hinge the decal in half to expose the liner tape and remove the liner paper.
6. Apply a little tension to the decal and squeegee the entire decal from the center towards the outside edge with overlapping
strokes.

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 General Information

7. Lightly hinge the other half of the decal to expose the liner tape and remove the liner paper.
8. Apply a little tension to the decal and squeegee the entire decal from the center towards the outside edge with overlapping
strokes. Be sure to overlap the outside edge of the decal with the squeegee.
9. Inspect the decal closely for entrapped air bubbles. Use the squeegee to push the air bubble to the outside edge.
10. Remove the premask liner from the decal beginning at one corner and carefully pull the premask liner off and onto itself at
a 180° angle.
IMPORTANT: When the premask is removed from the decal, the pulling force loosens the adhesive at the edges of the
decal. It is imperative to squeegee the entire decal with special attention to the edges of the decal.

50338

11. Do not allow the premask to remain on the decal for more than 24 hours after installation.
12. Squeegee the complete decal including all edges after the premask liner has been removed.

Entrapped Air Removal

The micro‑comply adhesive has a unique pattern to the adhesive that allows entrapped air to escape through very small
channels for a faster, easier installation. Always work from the center of the decal towards the edge. If the channels are closed
off, use an air release tool or straight pin to aid in removing the bubble. Puncture one end of the bubble and use your thumb to
push the entrapped air towards the puncture site. Do not use a knife or razor blade to puncture the decal.

Final Decal Squeegee

It is recommended to use a Meguiar's Supreme Shine Microfiber Towel for the final decal squeegee. With a firm hand pressure,
work the decal from the center out to the edge. Ensure to pay attention to the edge of the decal during this final decal
squeegee.
IMPORTANT: It is imperative to squeegee the entire decal with special attention to the edges of the decal.
IMPORTANT: Do not allow the new decal to have direct sunlight contact for a minimum of 24 hours.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1C-17

General Information

Notes:

Page 1C-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation

Important Information
1
Section 1D - Outboard Installation D
Table of Contents
Installation Information.......................................................1D-2 Start in Gear Protection.............................................. 1D-9
Boat Horsepower Capacity.........................................1D-2 Selecting Accessories for Your Outboard.................1D-10
Start in Gear Protection.............................................. 1D-2 Electric Fuel Pump .................................................. 1D-10
Selecting Accessories for Your Outboard...................1D-2 Top Cowl Removal and Installation.......................... 1D-10
Low Permeation Fuel Hose Requirement ..................1D-3 Lifting Outboard........................................................ 1D-10
Electric Fuel Pump .................................................... 1D-3 Determining the Mounting Height of the Outboard Jet
Installing Outboard.............................................................1D-3 .............................................................................. 1D-10
Mercury Marine Validated Engine Mounting Hardware Fastening the Outboard............................................1D-11
................................................................................ 1D-3 Steering Bracket, Steering Cable Installation........... 1D-12
Installation Specifications........................................... 1D-3 Steering Link Rod Fasteners.................................... 1D-12
Top Cowl Removal and Installation............................ 1D-4 Electrical Harness, Battery Connection, Fuel Tanks....... 1D-14
Lifting Outboard.......................................................... 1D-4 Remote Wiring Harness........................................... 1D-14
Drilling Outboard Mounting Holes (Manual Tilt Battery Cable Connections.......................................1D-16
Models)................................................................... 1D-4 Fuel Tanks................................................................1D-16
Drilling Outboard Mounting Holes (Power Trim and Control Cable Installation.................................................1D-16
Gas Assist)..............................................................1D-5 Throttle Cable Installation.........................................1D-16
Steering Bracket, Steering Cable Installation............. 1D-6 Shift Cable Installation..............................................1D-17
Steering Link Rod Fasteners...................................... 1D-7 Control Cable Installation ‑ Jet Outboard.........................1D-19
Installing Jet Outboard.......................................................1D-9 Throttle Cable Installation.........................................1D-19
Mercury Marine Validated Engine Mounting Hardware Shift Cable Installation..............................................1D-20
................................................................................ 1D-9 Installing Propeller........................................................... 1D-21
Boat Horsepower Capacity.........................................1D-9

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-1

Outboard Installation

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Extreme Grease Propeller shaft 8M0071842
Steering cable end
95 2-4-C with PTFE 92-802859A 1
Propeller shaft

Special Tools
Transom Drilling Fixture 91‑98234A2

Aids in engine installation by acting as a template for engine mounting holes.

5489

Installation Information
Boat Horsepower Capacity
! WARNING
Exceeding the boat's maximum horsepower rating can cause serious injury or death. Overpowering the boat can affect boat
control and flotation characteristics or break the transom. Do not install an engine that exceeds the boat's maximum power
rating.

Do not overpower or overload your boat. Most boats will carry a required capacity plate indicating the maximum acceptable
power and load as determined by the manufacturer following certain federal guidelines. If in doubt, contact your dealer or the
boat manufacturer.

U.S. COAST GUARD CAP ACITY

MAXIMUM HORSEPOWER XXX
MAXIMUM PERSON
CAPACITY (POUNDS) XXX
MAXIMUM WEIGHT
CAPACITY XXX
26777

Start in Gear Protection

! WARNING
Starting the engine with the drive in gear can cause serious injury or death. Never operate a boat that does not have a
neutral‑safety‑protection device.

The remote control connected to the outboard must be equipped with a start in neutral only protection device. This prevents the
engine from starting in gear.

Selecting Accessories for Your Outboard

Genuine Mercury Precision or Quicksilver Accessories have been specifically designed and tested for your outboard. These
accessories are available from Mercury Marine dealers.
IMPORTANT: Check with your dealer before installing accessories. The misuse of approved accessories or the use of
nonapproved accessories can damage the product.

Page 1D-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or
outboard operating system. Acquire and read the installation, operation and maintenance manuals for all your selected
accessories.

Low Permeation Fuel Hose Requirement

Required for outboards manufactured for sale, sold, or offered for sale in the United States.
• The Environmental Protection Agency (EPA) requires that any outboard manufactured after January 1, 2009 must use low
permeation fuel hose for the primary fuel hose connecting the fuel tank to the outboard.
• Low permeation hose is USCG Type B1‑15 or Type A1‑15, defined as not exceeding 15/gm²/24 h with CE 10 fuel at 23 °C
as specified in SAE J 1527 ‑ marine fuel hose.

Electric Fuel Pump

If an electric fuel pump is used, the fuel pressure must not exceed 27.58 kPa (4 psi) at the engine. If necessary, install a
pressure regulator to regulate the pressure.

Installing Outboard
Mercury Marine Validated Engine Mounting Hardware
IMPORTANT: Mercury Marine provides validated fasteners and installation instructions, including torque specifications, with all
of our outboards so they can be properly secured to boat transoms. Improper installation of the outboard can cause
performance and reliability issues that can lead to safety concerns. Follow all of the instructions relating to the outboard
installation. DO NOT mount any other accessory onto the boat with the fasteners provided with the outboard. For example, do
not mount tow sport bars or boarding ladders onto the boat using the mounting hardware included with the outboard. Installing
other products onto the boat that utilize the outboard mounting hardware will compromise the ability of that hardware to
properly and safely secure the outboard to the transom.
Outboards that require validated mounting hardware will have the following decal on the transom clamp.

51965

Installation Specifications
A
a - Minimum transom opening
B
A b - Engine center line for dual engines

2763

Minimum Transom Opening

Single engine (remote) 48.3 cm (19 in.)
Single engine (tiller) 76.2 cm (30 in.)
Dual engines 101.6 cm (40 in.)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-3

Outboard Installation

Engine Center Line

Minimum 66 cm (26 in.)

Top Cowl Removal and Installation

Top Cowl Removal
1. Unlock the cowl latch located at the rear of the engine by lifting the latch up.
2. Lift up on the rear of the cowl and disengage the front hook.

10170

Top Cowl Installation

1. Engage the front hook and push the top cowl onto the lower cowl.
2. Push the cowl latch down to lock the cowl in place.

Lifting Outboard
Use the lifting eye located aft of the flywheel to support the engine when installing the outboard.

10111

Drilling Outboard Mounting Holes (Manual Tilt Models)

IMPORTANT: Models not equipped with power trim or gas assist must have the transom clamps contacting the top of the
transom, and the clamp screws tightened, prior to drilling the mounting bolt holes through the transom.
1. Place outboard on center line of transom.

27005

Page 1D-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
2. Tighten the transom clamp bolts.

15728

3. Use a long drill bit to drill the two lower 8 mm (0.315 in.) holes through the transom using the transom clamps as a
template for the bolt hole pattern.

a - Upper transom clamp hole

a b - Lower transom clamp hole

b
15949

4. Apply marine sealer to shanks of bolts. Do not apply marine sealer to the threads of the bolts.
5. Secure the engine to the transom with the mounting hardware supplied with the engine. Tighten mounting hardware
securely.

a - Bolt (2)
b - Washer (2)
c - Locknut (2)

b c
a 15729

Drilling Outboard Mounting Holes (Power Trim and Gas Assist)

1. Use the transom drilling fixture for drilling the transom mounting holes.

b a - Drill guide holes

b - Transom drilling fixture
c - Transom center line

c 2757

Transom Drilling Fixture 91‑98234A2

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-5

Outboard Installation
2. Drill four 12 mm (0.472 in.) mounting holes.

3973

3. Install the outboard so that the anti‑ventilation plate is in‑line or within 25 mm (1 in.) of the bottom of the boat.

a - Anti‑ventilation plate
b - In‑line or within 25 mm (1 in.)
a

8045
4. Apply marine sealer to shanks of bolts. Do not apply marine sealer to the threads of the bolts.
5. Fasten outboard with provided mounting hardware shown. Tighten mounting hardware securely.
The outboard must be secured to the transom with the two transom bracket clamp screws and four 12 mm (0.472 in.) diameter
mounting bolts and locknuts provided. Install two bolts through the upper set of mounting holes and two bolts through the lower
set of mounting slots.

e a- Bolt
b- Washer 25.4 mm (1 in.)
c c- Washer 34 mm (1.312 in.)
d- Locknut
a d e- Transom clamp bolt

23703
b

Steering Bracket, Steering Cable Installation

1. Install the steering bracket with two washers and two 30 x 80 mm bolts. Tighten the steering bracket bolts to the specified
torque.

Description Nm lb‑in. lb‑ft

Steering bracket bolt 30 – 22
2. Lubricate entire steering cable end with 2‑4‑C with PTFE.

10261

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Steering cable end 92-802859A 1
3. Install the steering cable seal onto the end of the tilt tube.

Page 1D-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
4. Insert the steering cable into the tilt tube and secure with the steering cable nut. Tighten the steering cable nut to the
specified torque.

b a - Steering cable nut

a c b - Steering bracket bolt and washer (2)
c - Steering cable seal

59494

Description Nm lb‑in. lb‑ft

Steering cable nut 47.5 – 35

Steering Link Rod Fasteners

IMPORTANT: The steering link rod that connects the steering cable to the engine must be fastened using the steering link rod
fastening hardware supplied with the engine. Never replace the locknuts with nonlocking nuts. Nonlocking nuts may loosen and
vibrate off, allowing the link rod to disengage.

! WARNING
Improper fasteners or improper installation procedures can result in loosening or disengagement of the steering link rod. This
can cause a sudden, unexpected loss of boat control, resulting in serious injury or death due to occupants being thrown
within or out of the boat. Always use required components and follow instructions and torque procedures.

1. Install the steering link rod onto the steering bracket aft threaded hole.

59496

2. Assemble the steering link rod onto the steering bracket with the bolt, two washers, spacer, and a locknut. Do not tighten
the bolt or locknut at this time.

e a- Bolt
d
f b- Washer
c- Spacer
d- Steering bracket
e- Locknut
f- Washer
c
b
a
59497

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-7

Outboard Installation
3. Install the loose end of the steering link onto the steering cable and secure with a washer and locknut. Tighten the locknut
securely and then back the nut off 1/4 turn.

a - Washer
b - Locknut

a
b
59499
4. Tighten the link rod bolt to the specified torque.
5. Secure the link rod bolt so it does not loosen and tighten the locknut to the specified torque.

a - Link rod bolt

b b - Locknut

a
59500

Description Nm lb‑in. lb‑ft

Link rod bolt 27 – 20
Locknut 27 – 20

6. Secure the battery cables to the throttle/shift cable with two cable ties to prevent contact with the steering components.

59502

Page 1D-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation

Installing Jet Outboard

Mercury Marine Validated Engine Mounting Hardware
IMPORTANT: Mercury Marine provides validated fasteners and installation instructions, including torque specifications, with all
of our outboards so they can be properly secured to boat transoms. Improper installation of the outboard can cause
performance and reliability issues that can lead to safety concerns. Follow all of the instructions relating to the outboard
installation. DO NOT mount any other accessory onto the boat with the fasteners provided with the outboard. For example, do
not mount tow sport bars or boarding ladders onto the boat using the mounting hardware included with the outboard. Installing
other products onto the boat that utilize the outboard mounting hardware will compromise the ability of that hardware to
properly and safely secure the outboard to the transom.
Outboards that require validated mounting hardware will have the following decal on the transom clamp.

51965

Boat Horsepower Capacity

! WARNING
Exceeding the boat's maximum horsepower rating can cause serious injury or death. Overpowering the boat can affect boat
control and flotation characteristics or break the transom. Do not install an engine that exceeds the boat's maximum power
rating.

Do not overpower or overload your boat. Most boats will carry a required capacity plate indicating the maximum acceptable
power and load as determined by the manufacturer following certain federal guidelines. If in doubt, contact your dealer or the
boat manufacturer.

U.S. COAST GUARD CAP ACITY

MAXIMUM HORSEPOWER XXX
MAXIMUM PERSON
CAPACITY (POUNDS) XXX
MAXIMUM WEIGHT
CAPACITY XXX
26777

Start in Gear Protection

! WARNING
Starting the engine with the drive in gear can cause serious injury or death. Never operate a boat that does not have a
neutral‑safety‑protection device.

The remote control connected to the outboard must be equipped with a start in neutral only protection device. This prevents the
engine from starting in gear.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-9

Outboard Installation

Selecting Accessories for Your Outboard

Genuine Mercury Precision or Quicksilver Accessories have been specifically designed and tested for your outboard. These
accessories are available from Mercury Marine dealers.
IMPORTANT: Check with your dealer before installing accessories. The misuse of approved accessories or the use of
nonapproved accessories can damage the product.
Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or
outboard operating system. Acquire and read the installation, operation and maintenance manuals for all your selected
accessories.

Electric Fuel Pump

If an electric fuel pump is used, the fuel pressure must not exceed 27.58 kPa (4 psi) at the engine. If necessary, install a
pressure regulator to regulate the pressure.

Top Cowl Removal and Installation

Top Cowl Removal
1. Unlock the cowl latch located at the rear of the engine by lifting the latch up.
2. Lift up on the rear of the cowl and disengage the front hook.

10170

Top Cowl Installation

1. Engage the front hook and push the top cowl onto the lower cowl.
2. Push the cowl latch down to lock the cowl in place.

Lifting Outboard
Use the lifting eye located aft of the flywheel to support the engine when installing the outboard.

10111

Determining the Mounting Height of the Outboard Jet

The following outboard mounting height settings will work good for most applications, however, because of different boat/hull
designs, the setting should be checked by test running the boat.
• Installing the outboard too high on the transom will allow the water intake to suck in air and cause cavitation. (Cavitation
will cause the engine to overspeed in spurts and reduce thrust.) This condition should be avoided by proper height setting.

Page 1D-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
• Installing the outboard too low on the transom will allow excessive drag.

Boats with a "V" Bottom Hull

1. Measure the width of the leading edge on the water intake housing. Make a horizontal line on the transom up from the "V"
bottom the same length as the width of the water intake housing.

a - Horizontal line
b - Width of the leading edge on the water intake housing

b 22401

2. Place (center) the outboard on the boat transom. Set the height of the outboard on the boat transom so that the front edge
of the water intake housing is in line with the horizontal line made in step 1. Temporarily clamp the outboard to the transom
at this position.
3. Fasten the outboard to the transom at this height. Refer to Fastening the Outboard.

22403

Boats with a Flat Bottom Hull

1. Place (center) the outboard on the boat transom. Set the height of the outboard on the boat transom so that the front edge
of the water intake housing is in line with the bottom of the boat as shown. Temporarily clamp the outboard to the transom
at this position.
2. Fasten outboard to the transom at this height. Refer to Fastening the Outboard.

22403

Fastening the Outboard

1. Drill four 13.5 mm (17/32 in.) mounting holes.
2. Install the outboard so that the water intake housing is set at the correct height. Refer to Determining the Mounting
Height of the Outboard Jet.
3. Apply marine sealer to shanks of bolts (purchase locally). Do not apply marine sealer to the threads of the bolts.
4. Fasten the outboard with provided mounting hardware shown. Tighten mounting hardware securely.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-11

Outboard Installation
The outboard must be secured to the transom with the two transom bracket clamp screws and four 13 mm (1/2 in.) diameter
mounting bolts and locknuts provided. Install two bolts through the upper set of mounting holes and two bolts through the lower
set of mounting slots.

a- Bolt
b b- Transom clamp bolt
c c- Washer
d- Nut
a d

10175

Steering Bracket, Steering Cable Installation

1. Install the steering bracket with two washers and two 30 x 80 mm bolts. Tighten the steering bracket bolts to the specified
torque.

Description Nm lb‑in. lb‑ft

Steering bracket bolt 30 – 22
2. Lubricate entire steering cable end with 2‑4‑C with PTFE.

10261

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Steering cable end 92-802859A 1
3. Install the steering cable seal onto the end of the tilt tube.
4. Insert the steering cable into the tilt tube and secure with the steering cable nut. Tighten the steering cable nut to the
specified torque.

b a - Steering cable nut

a c b - Steering bracket bolt and washer (2)
c - Steering cable seal

59494

Description Nm lb‑in. lb‑ft

Steering cable nut 47.5 – 35

Steering Link Rod Fasteners

IMPORTANT: The steering link rod that connects the steering cable to the engine must be fastened using the steering link rod
fastening hardware supplied with the engine. Never replace the locknuts with nonlocking nuts. Nonlocking nuts may loosen and
vibrate off, allowing the link rod to disengage.

! WARNING
Improper fasteners or improper installation procedures can result in loosening or disengagement of the steering link rod. This
can cause a sudden, unexpected loss of boat control, resulting in serious injury or death due to occupants being thrown
within or out of the boat. Always use required components and follow instructions and torque procedures.

Page 1D-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
1. Install the steering link rod onto the steering bracket aft threaded hole.

59496

2. Assemble the steering link rod onto the steering bracket with the bolt, two washers, spacer, and a locknut. Do not tighten
the bolt or locknut at this time.

e a- Bolt
d
f b- Washer
c- Spacer
d- Steering bracket
e- Locknut
f- Washer
c
b
a
59497
3. Install the loose end of the steering link onto the steering cable and secure with a washer and locknut. Tighten the locknut
securely and then back the nut off 1/4 turn.

a - Washer
b - Locknut

a
b
59499
4. Tighten the link rod bolt to the specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-13

Outboard Installation
5. Secure the link rod bolt so it does not loosen and tighten the locknut to the specified torque.

a - Link rod bolt

b b - Locknut

a
59500

Description Nm lb‑in. lb‑ft

Link rod bolt 27 – 20
Locknut 27 – 20

6. Secure the battery cables to the throttle/shift cable with two cable ties to prevent contact with the steering components.

59502

Electrical Harness, Battery Connection, Fuel Tanks

Remote Wiring Harness
1. Remove the three access cover bolts. Remove the access cover and cable rubber grommet.

10113

2. Remove the cotter pin retainers and washers from the shift actuating lever, shift link, and throttle actuating lever.
3. Remove the shift link from the shift actuating lever.

Page 1D-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
4. Loosen the bolt securing the control harness retainer bracket.

c a - Shift link, cotter pin retainer, and washer

d
b - Shift actuating lever, cotter pin retainer, and
b washer
c - Throttle actuating lever, cotter pin retainer,
and washer
d - Shift link
a
e - Bolt securing harness retainer bracket
e

10114

5. Remove the bolt securing the cable barrel retainer to the cowl.

10127

6. Connect the remote harness to the engine harness connector.

7. Route the harness below the shift actuating lever pin.
8. Route the harness between the barrel support.

a- Harness connector
d b- Shift actuating lever pin
b c c- Harness retainer bracket
d- Barrel support

a
10128

9. Ensure the harness retainer bracket is over the remote harness. Secure harness retainer bracket with bolt. Tighten bolt to
the specified torque.
10. Install the shift link to the shift actuating lever.

b a- Washer and cotter pin retainer securing shift link

d b- Shift actuating lever
c
c- Harness retainer bracket bolt
d- Shift link

10135

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-15

Outboard Installation

Description Nm lb. in. lb. ft.

Bolt 6 53

Battery Cable Connections

IMPORTANT: To prevent damage to the engine charging system when the battery cables are not connected to a battery,
ensure the battery cable ends are thoroughly insulated.

Single Outboard

a a - Red sleeve ‑ positive (+)

b - Black sleeve ‑ negative (–)
c - Cranking battery
(+)

b c

(-) 15496

Dual Outboards
Connect a common ground cable (wire size same as engine battery cables) between negative (–) terminals on starting
batteries.

a a- Red sleeve ‑ positive (+)

b- Black sleeve ‑ negative (–)
c- Ground cable
d- Cranking battery

b
a (-)
d

b
c (-)
d

15497

Fuel Tanks
Portable Fuel Tank
Select a suitable location in the boat within the engine fuel line length limitations and secure the tank in place.

Permanent Fuel Tank

Permanent fuel tanks should be installed in accordance with industry and federal safety standards, which include
recommendations applicable to grounding, anti‑siphon protection, ventilation, etc.

Control Cable Installation

Throttle Cable Installation
Install cables into the remote control following the instructions provided with the remote control.
1. Move the remote control handle from neutral into forward and advance the handle to full speed position.
NOTE: The throttle cable is the second cable to move when moving the control box out of neutral.

Page 1D-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
2. Install the throttle cable to the throttle actuating lever. Secure with a washer and cotter pin retainer.
3. Adjust the throttle cable barrel, so when barrel is installed into the throttle cable barrel support, no play can be felt when
lightly pushing the throttle cam with your finger.

b a - Throttle cam (no play can be felt when

lightly pushing)
a b - Throttle cable barrel support
c - Throttle actuating lever

c
10136

4. Slowly return the remote control handle back to the neutral detent position.
5. Inspect cam roller to ensure it is not contacting the cam.
6. Readjust the throttle cable barrel if the cam roller is touching the cam.

a a - Cam roller
b - Throttle cam

b
15952

Shift Cable Installation

Install cables into the remote control following the instructions provided with the remote control.
1. Locate the center point of the slack or lost motion that exists in the shift cable as follows:
a. Move the remote control handle from neutral into forward and advance the handle to full speed position. Slowly return
the handle back to the neutral. Place a mark ("a") on the cable end guide.
b. Move the remote control handle from neutral into reverse and advance the handle to full speed position. Slowly return
the handle back to the neutral. Place a mark ("b") on the cable end guide.
c. Make a center mark ("c"), midway between marks ("a" and "b"). Align the cable end guide with this center mark when
installing cable to the engine.

6098

2. Ensure the engine is in neutral.

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Outboard Installation
3. Ensure the control box is in neutral.
4. Install the shift cable on shift actuating lever. Secure with washer and cotter pin retainer. Adjust cable barrel so the center
mark on the cable guide is in alignment when the shift cable barrel is in the barrel support in the cowl.

c a - Center mark on cable guide

b - First mark on cable guide
c - Shift cable barrel

a
15896

5. Check shift cable adjustments as follows:

a. Shift remote control into forward. The propeller shaft should be locked in gear. If not, adjust the barrel closer to the
cable end.
b. Shift remote control into reverse while turning propeller. The propeller shaft should be locked in gear. If not, adjust the
barrel away from the cable end. Repeat steps a through c.
c. Shift remote control back to neutral. The propeller shaft should turn freely without drag. If not, adjust the barrel closer
to the cable end. Repeat steps a through c.
6. Install the cable grommet.
7. Secure the throttle and shift cable barrels with the cable barrel retainer.
8. Tighten the cable barrel retainer bolt to the specified torque.

a - Cable barrel retainer

a
b - Cable barrel retainer bolt
c - Cable grommet

15855

Description Nm lb. in. lb. ft.

Cable barrel retainer bolt 6 53
9. Install the access cover and secure with three bolts. Tighten bolts to the specified torque.

15858

Page 1D-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation

Description Nm lb. in. lb. ft.

Access cover bolt (3) 6 53

Control Cable Installation ‑ Jet Outboard

Throttle Cable Installation
Install the cables into the remote control following the instructions provided with the remote control.
1. Move the remote control handle from neutral into forward and advance the handle to full speed position.
NOTE: The throttle cable is the second cable to move when moving the control box out of neutral.
2. Install the throttle cable to the throttle actuating lever. Secure with a washer and cotter pin retainer.
3. Adjust the throttle cable barrel, so when barrel is installed into the throttle cable barrel support, no play can be felt when
lightly pushing the throttle cam with your finger.

a a - Throttle cam (no play can be felt when

lightly pushing)
b
b - Throttle cable barrel
c - Throttle actuating lever

24902
c
4. Slowly return the remote control handle back to the neutral detent position.
5. Inspect the cam roller to ensure it is not contacting the cam.
6. Adjust the throttle cable barrel if the cam roller is touching the cam.

a a - Cam roller
b - Throttle cam

b
15952

7. Install the cable grommet.

8. Secure the throttle cable barrel with the cable barrel retainer.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 1D-19

Outboard Installation
9. Tighten the cable barrel retainer bolt to the specified torque.

b c a - Cable barrel retainer

a
b - Cable barrel retainer bolt
c - Cable grommet

24903

Description Nm lb. in. lb. ft.

Cable barrel retainer bolt 6 53
10. Install the access cover and secure with three bolts. Tighten bolts to the specified torque.

15858

Description Nm lb. in. lb. ft.

Access cover bolt (3) 10 88

Shift Cable Installation

! WARNING
If not properly installed, the reverse gate can interfere with water coming off the rudder, suddenly and unexpectedly slowing
the boat. This can cause serious injury or death from occupants being thrown within or out of the boat. Adjust the shift cable
to prevent the reverse gate from interfering with water flow off the rudder.

1. Attach the shift cable to the shift cam with a flat washer and a self‑locking nylon insert locknut as shown. Tighten the
locknut against the flatwasher, then back‑off the locknut 1/4 turn.
2. Place the remote control handle into full forward position.
3. Adjust the shift cable adjustment barrel so that the roller is at the full end of travel (bottom) in the shift cam.

Page 1D-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Outboard Installation
4. Attach the shift cable adjustment barrel to the bracket with a bolt and locknut. Tighten the bolt until it seats against the
adjustment barrel, then back‑off the bolt 1/4 turn. Hold the bolt from turning, and tighten the locknut on the bolt. The
adjustment barrel must be free to pivot.

d a- Roller
b- Shift cam
c- Shift cable
c d- Shift cable adjustment barrel

24905

5. Check the shift cable adjustment in forward shift position. The correct shift adjustment will position the cam far enough on
the roller to lock the reverse gate into forward position. Push on the reverse gate by hand to verify it is locked into position.
The reverse gate should not move when pushed toward the neutral position.
IMPORTANT: The forward locking of the reverse gate must be met. If not, readjust the shift cable.

Installing Propeller
! WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.

1. Shift the outboard to neutral (N) position.

F
NEUTRAL F
NEUTRAL
START R
START

26838 10051

2. Remove the spark plug leads to prevent the engine from starting.

26899

3. Coat the propeller shaft with Extreme Grease or 2‑4‑C with PTFE.
IMPORTANT: To prevent the propeller hub from corroding and seizing to the propeller shaft (especially in saltwater),
always apply a coat of the recommended lubricant to the entire propeller shaft at the recommended maintenance intervals
and also each time the propeller is removed.

10087

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Outboard Installation

Tube Ref No. Description Where Used Part No.

Extreme Grease Propeller shaft 8M0071842

95 2-4-C with PTFE Propeller shaft 92-802859A 1

4. Install the front thrust hub, propeller, rear thrust washer and propeller nut onto the shaft.

a c a- Propeller nut
b
d
b- Rear thrust washer
c- Propeller
d- Forward thrust hub

10077

5. Place a block of wood between the gearcase and the propeller and torque the propeller nut to specification.
NOTE: If the propeller nut does not align with the propeller shaft hole after tightening to the specified torque, then tighten
the nut further to align it with the hole in the propeller shaft.
6. Align the propeller nut with the propeller shaft hole. Insert a new cotter pin in the hole and bend the cotter pin ends.

28353 28351

Description Nm lb‑in. lb‑ft

Propeller nut 25 – 18

Page 1D-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

Electrical
Section 2A - Ignition
Table of Contents 2
A
Ignition Specifications........................................................ 2A-2 Stator Removal and Installation................................2A-14
Theory of Operation .......................................................... 2A-3 Crank Position Sensor (CPS)................................... 2A-15
Troubleshooting without a Computer Diagnostic System Crank Position Sensor Removal and Installation......2A-15
(CDS)............................................................................. 2A-4 Crank Position Sensor Testing................................. 2A-18
Troubleshooting with the Computer Diagnostic System Electronic Control Module (ECM)............................. 2A-20
(CDS)............................................................................. 2A-4 ECM Removal and Installation................................. 2A-20
Accessing ECM Information with the CDS.........................2A-4 Ignition Coils............................................................. 2A-21
Fault Information.........................................................2A-5 Ignition Coil Removal and Installation.......................2A-21
Warning System.................................................................2A-6 Ignition Coil Testing.................................................. 2A-22
Warning Horn..............................................................2A-6 Engine Temperature Coolant Sensor (ETC).............2A-24
Warning Light..............................................................2A-6 ETC Removal and Installation.................................. 2A-24
Warning System Operation.........................................2A-6 ETC Sensor Test...................................................... 2A-25
Engine Overheat.........................................................2A-6 Oil Pressure Sensor..................................................2A-26
Low Oil Pressure........................................................ 2A-7 Oil Pressure Switch Removal and Installation.......... 2A-26
Engine Overspeed Limiter.......................................... 2A-7 Oil Pressure Switch Test.......................................... 2A-28
Warning Light and Warning Horn Wire Diagrams..............2A-7 Manifold Air Temperature (MAT) Sensor .................2A-29
Warning Light Wire Diagram.......................................2A-7 MAT Sensor Removal and Installation..................... 2A-29
Warning Horn Wire Diagram—Tiller Handle Models MAT Sensor Test......................................................2A-31
................................................................................ 2A-8 Manifold Absolute Pressure (MAP) Sensor ............. 2A-31
Ignition Components.......................................................... 2A-8 MAP Sensor Removal and Installation..................... 2A-31
Flywheel/Timing Belt Cover........................................ 2A-8 MAP Sensor Test......................................................2A-33
Flywheel Assembly..................................................... 2A-8 Throttle Position Sensor (TPS)................................. 2A-33
Stator.......................................................................... 2A-8 TPS Test...................................................................2A-34
Stator Testing............................................................. 2A-9 Tiller Handle Stop Button and Lanyard Stop Switch
Flywheel Removal and Installation........................... 2A-11 Test....................................................................... 2A-35

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Ignition

Ignition Specifications
Ignition Specifications at 20 °C (68 °F)
Ignition type Computer controlled CDI (capacitor discharge ignition)
Spark plug NGK DCPR6E
Spark plug gap 0.8–0.9 mm (0.031–0.035 in.)
Firing order 1, 3, 2
Ignition timing at idle 5° ± 5° BTDC
Ignition timing at WOT 38° BTDC
RPM overspeed 6300 RPM
ECM RPM limiter (Guardian) 2800 RPM
Over temperature 90 °C (194 °F)
Low oil pressure (over 5 seconds) 24.5 kPa (3.5 psi)
Crankshaft position sensor 148–222 ohms
Ignition coil
Primary 0.17–0.23 ohms
Secondary 3.3–4.9 k ohms
Spark plug lead (between spark plug cap and black lead) 7.1–11.1 k ohms

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
6 Dielectric Grease Oil pressure switch wire connection 92-823506 1
Loctite 567 PST Pipe ETC threads
9 92-809822
Sealant Oil pressure switch threads
25 Liquid Neoprene All ring terminal connections 92- 25711 3

Special Tools
CDS G3 Diagnostic Tool Kit 8M0114141

Interfaces CDS G3 software to SmartCraft network.

NOTE: This kit includes download instructions and a license key.

60575

Adapter Harness 84‑899150T01

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).
22175

Adapter Harness 84‑822560A7

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).

13422

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 Ignition

DMT 2004 Digital Multimeter 91‑892647A01

Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC

V Hz
H z TEMP
mA
A
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
mV IG
OFF IP

TEMP

A mA COM V Hz

4516

Flywheel Holding Tool 91‑52344

Holds and/or turns the flywheel while making engine repairs, also used to torque
the flywheel or the engine coupler.

4738

Flywheel Puller/Lifting Ring 91‑83164M

Removes flywheel from engine. Used for lifting powerhead/engine.

8744

Extension Cable 84‑825003A 1

Data link extension harness (3.05 m [10 ft.]) between the adapter harness and
the Digital Diagnostic Terminal or Computer Diagnostic System (CDS).

4012

Theory of Operation
The ignition system uses a microcomputer‑controlled CDI (Capacitor Discharge Ignition) system. This system provides quick
voltage build‑up, and strong spark required for high power and high performance engines. The CDI ignition system does not
incorporate mechanically operated points, therefore making this CDI unit virtually maintenance‑free.
This is an alternator driven, synchronous multi‑port fuel injection outboard. No battery voltage source is required for the engine
operations. The flywheel must be rotating 250 RPM to generate the minimum five volts DC required to energize the ECM, and
maintain an active warning system.
As the flywheel rotates, alternating electrical current is produced by the stator charge coils. This current is rectified by diodes in
the Electronic Control Module (ECM) for the ignition system, and fuel delivery system. Alternating electrical current is also
produced by the stator charge coils and is rectified by diodes in the voltage regulator/rectifier for charging the battery. When the
ignition driver is off, the DC voltage is stored and elevated by a capacitor inside the ECM. When the capacitor voltage is
charged to its potential, a gate signal is applied and the residual current is dissipated through the primary winding of the ignition
coils.
The timing of the gate signal is dependent on the ECM programed logic recognizing the engine crankshaft position and engine
RPM. The flywheel is cast with a timing key located under the starter ring gear. The timing key rotates past the Crank Position
Sensors (CPS), collapsing a magnetic field. The crankshaft position and the engine RPM is based on the magnetic field
collapse of the CPS, generating a gate signal to the ECM. The Crank Position Sensors are spaced 120° apart.
The ECM also requires information from the water temperature sensor, oil pressure sensor, manifold absolute pressure sensor,
and air temperature sensor to formulate the correct ignition timing, fuel injection timing, fuel injection volume (duration). The
ECM uses all of the sensor to monitor the engines condition which are directly related to the warning system.

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Ignition

Troubleshooting without a Computer Diagnostic System (CDS)

Troubleshooting without the computer diagnostic system (CDS) is limited to checking resistance on some of the sensors.
Typical failures usually do not involve the PCM. Connectors, set‑up, and mechanical wear are most likely at fault.
• Verify the ignition coils are securely installed (pushed in) into the spark plugs.
• The engine may not run or may not run above idle with the wrong spark plugs installed.
• Swap ignition coils to see if the problem follows the coil or stays with the particular cylinder.
IMPORTANT: Disconnecting a sensor while the engine is running may result in a fault recording in the PCM Fault History. Use
the CDS to view the PCM fault history when troubleshooting/repair is completed.
• If all cylinders exhibit similar symptoms, the problem is with a sensor or harness input to the PCM.
• If problem is speed related or intermittent, it is probably connector or contact related. Inspect connectors for corrosion,
loose wires, or pins pushed back into connector. Verify the connectors are properly seated.
• Inspect the harness for damage: pinched or cut wires and chafing.
• Secure the grounds and all connections involving ring terminals. Apply Liquid Neoprene to all ring terminal connections.

Tube Ref No. Description Where Used Part No.

25 Liquid Neoprene All ring terminal connections 92- 25711 3
• Inspect the fuel pump harness connector for corrosion, loose wires, or pins pushed back into connector.
• Check the fuel pump pressure.

Troubleshooting with the Computer Diagnostic System (CDS)

The ECM is designed that if a sensor fails, the ECM will compensate so that the engine does not go into an over‑rich condition.
Because of this, disconnecting a sensor for troubleshooting purposes may have no noticeable effect.
The CDS has been developed specifically to help technicians diagnose and repair Mercury Marine 2 and 4 cycle engines.

CDS G3 Diagnostic Tool Kit 8M0114141

Attach the 84‑899150T01 diagnostic cable to the ECM diagnostic port and attach the 84‑822560A7 adapter to the
84‑899150T01 diagnostic cable. The CDS will monitor sensors and ECM data values including status switches. The ECM
program can help diagnose intermittent engine problems. It can record the state of the engine sensors and switches for a
period of up to 10 minutes, which then can be played back and analyzed.

a a - Diagnostic port
b b - ECM

23249

Adapter Harness 84‑899150T01

Adapter Harness 84‑822560A7

When using the CDS for troubleshooting, follow the CDS driven troubleshooting menu for the complete diagnostic
troubleshooting procedures.

Accessing ECM Information with the CDS

The CDS allows the technician to specifically identify the engine to be tested. It is important to accurately identify the engine
because in many cases, the available testing options depend on the engine identified. It is also capable of storing customer
contact information and will identify the required diagnostic cables for the engine selected.

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 Ignition

CDS G3 Diagnostic Tool Kit 8M0114141

The Pinpoint Diagnostics (when applicable) allows the technician to identify the cause of a fault code down to the component
level. Pinpoint Diagnostic test results can be stored in the CDS.
Fault codes can be displayed active or historic. The Fault Status displays the code number, description, and the source of the
faults. Fault Hours displays a fault number and text that corresponds to the exact moment in the engines' run history the fault
was set.
When the 84‑899150T01 diagnostic cable is plugged into the ECM diagnostic port, a special service mode is activated within
the ECM. When the special service mode is activated, the ECM will not log run time, nor will it allow any fault hours to be set.
Any previously logged run time and fault hours can be reviewed for diagnostic purposes, but the run time will not increase and
no new fault hours can be set when the ECM is in the service mode. During a water test, the data stream and any faults that
occur during the water test, will be recorded. The water test does not affect the logging of faults, run history, or system
information.
The diagnostic cable connection supplies power to the ECM. Disconnecting sensors and actuators while the ECM is powered
up in the special service mode, will cause faults to be displayed in the faults status screen. These faults will not be recorded in
the memory fault hours. The CDS will not clear (erase) faults hours at the time of this service manual printing.
The System Information screen will display an alpha‑numeric code identifying a specific calibration in the ECM.

Fault Information
Fault Information
CDS Screen Display Description
ACG Coil 1, 2, 3 ACG Coil faults #1 through #3
IGN 1, 2, 3 Ignition coil fault code #4 through #6.
INJ 1, 2, 3 Fuel injector fault code #7 through #9.
Fuel Pump Circuit High pressure fuel pump fault code #10
(Idle Speed Control) Fault code #11. May be referred to as IAC (Idle
ISC
Air Control).
Fault Status ‑ Active Faults
Throttle Position Sensor Throttle position sensor fault code #12.
Intake Temperature Sensor Intake temperature sensor fault code #13.
Water Temperature Sensor Water temperature sensor fault code #14.
Pressure sensor fault code #15. May be referred to as MAP
Pressure Sensor
(Manifold Absolute Pressure).
Oil Pressure Sensor Oil pressure sensor fault code #16.

Data Stream Information

CDS Screen Display Description
ACG Stator voltage driving the engine operating systems
Engine Speed Engine RPM
The amount of voltage the ECM is receiving through the engine stator or
Driver Power
diagnostic cable.
Baro Pressure Ambient air pressure.
Manifold Pressure May be referred to as MAP (Manifold Absolute Pressure).
Throttle Position Percentage of throttle angle.
Ignition Timing Ignition timing displayed in degrees BTDC.
Data List IAC Duty Cycle ISC (Idle Speed Control) activation percentage 0 ‑ 100%.
Engine Coolant Temperature Cylinder block water temperature.
Fuel Flow Rate Amount of calculated fuel consumption.
INJ Pulse Width Fuel injector activation duration ms (milliseconds).
Low oil pressure displayed in the CDS as:
Low Oil Pressure Switch • Engine running ON (adequate oil pressure)
• Engine not running OFF (low oil pressure)
Ignition key is OFF, lanyard stop switch active: displayed in the CDS as ON.
Stop Switch
Ignition key is ON, lanyard stop switch is open: displayed in the CDS as OFF.

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Ignition

Warning System
Warning Horn
Remote control models will have the warning horn located inside the remote control or connected to the ignition key switch.
Tiller handle models will have the warning horn located in the engine cowl.

Warning Light
The warning light will turn on or flash to alert the operator to the warning system situations listed the the following chart.

15732

Warning System Operation

The warning horn will emit either a continuous beep or intermittent short beeps and engine speed will be limited. This will alert
the operator and help identify the following listed situations.

Warning System
Engine Speed
Function Sound Warning Light Description Limited to 2800
RPM
Start up One beep On for 5 seconds Normal system test
Engine over temperature Continuous On Engine overheat X
Low oil pressure Continuous On Low oil pressure X
Engine speed exceeds maximum
Engine overspeed Continuous On
allowable RPM
Engine speed will be limited.
Water temp or MAP sensor Intermittent short
Flashes Consult your dealer for X
out of range beep
assistance.

Engine Overheat
If the engine overheats, immediately reduce throttle speed to idle. Shift outboard into neutral and check for a steady stream of
water coming out of the water pump indicator hole.

9647

If no water is coming out of the water pump indicator hole, or flow is intermittent, stop engine and check cooling water intake
holes for obstruction. If no obstruction is found, this may indicate a blockage in the cooling system or a water pump problem.
Have the outboard checked by your dealer. Operating the engine while overheated will cause engine damage.
If a steady flow of water is coming out of the water pump indicator hole and the engine continues to overheat, consult your
dealer. Operating an overheated engine will cause engine damage.
NOTE: Should overheating occur and you are stranded, stop the engine and allow it to cool down. This will usually allow some
additional low speed (idle) running time before the engine starts to overheat again.

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 Ignition

Low Oil Pressure

The warning system will be activated if the oil pressure drops too low. First, stop the engine and check the oil level. Add oil if
necessary. If the oil is at the recommended level and the warning horn continues to sound, consult your dealer. Engine speed
will be limited to 2800 RPM, however, you should not continue to run engine.

Engine Overspeed Limiter

Some causes of engine overspeed are as follows:
• Propeller ventilation
• A propeller which has an incorrect pitch or diameter
• Propeller hub slippage
• Outboard mounted too high on the transom
• Tilting the outboard out beyond a vertical position
• Cavitation of the propeller due to rough water or obstruction in the boat hull
When the engine overspeed limiter is activated, the engine timing will be momentarily retarded to decrease the engine speed.
Excessive overspeed (above 6300 RPM) will result in cutout of the cylinders to prevent operation above this limit.

Warning Light and Warning Horn Wire Diagrams

Warning Light Wire Diagram

a - ECM engine harness

b connector
b - Warning light

WHT/RED
LT GRN
18 1
1 BLU WHT/RED

10 LT GRN

a
22604

34 17

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Ignition

Warning Horn Wire Diagram—Tiller Handle Models

18 1
1 BLU b

RED

YEL
RED
11 YEL

a
22603
34 17

a - ECM engine harness connector

b - Warning horn

Ignition Components
Flywheel/Timing Belt Cover
The purpose of the flywheel cover is to provide basic protection against accidental contact with the flywheel, starter motor
pinion gear and camshaft drive belt while the engine is running.
Removal of the flywheel cover provides access to the flywheel, camshaft drive belt tensioner, camshaft drive belt, starter motor
pinion gear, and the crankshaft position sensors.

Flywheel Assembly
The flywheel is weighted and balanced to improve engine running characteristics. The flywheel is secured to the crankshaft
with a washer and nut. The flywheel has a ring gear that is used with the starter motor to start the engine electrically. Below the
ring gear, the flywheel is cast with a timing key. As the timing key passes the first crankshaft position sensor (CPS), an
electrical pulse is generated within the CPS and is sent to the Electronic Control Module (ECM). The ECM then calculates the
position of the crankshaft based on the electrical pulse generated when the timing key passes the second CPS. The ECM will
use this information to regulate ignition and fuel injector timing. The flywheel also has magnets on the inside circumference to
generate AC voltage needed for the ECM to operate. These same magnets are also used to generate voltage to charge a
battery.

Stator
The stator is located under the flywheel. The stator is composed of several layers of steel plates called a bobbin laminate. The
bobbin laminate is wound with a fine wire in order to generate a high voltage that is required for the ECM, ignition coils, and
high pressure fuel pump to function. There are three separate windings on the stator that supply voltage for a specific
component within the fuel system, ignition system, and battery charging system. As the flywheel rotates, magnets secured to
the inside of the flywheel pass close to the stator bobbins, generating a strong alternating current. The AC current is sent to the
ECM where it is rectified to direct current (DC) voltage to energize the ECM, high pressure fuel pump, IAC, fuel injectors, and
the warning system. There is also a heavy gauge wire wound on the bobbins to generate voltage required to maintain the
battery. This voltage is rectified external of the ECM.

Page 2A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

Stator Testing

d f

RED
GRN
BLK
BLK

BLK
e

RED
RED
YEL
YEL
YEL

RED
a RED
YEL
YEL

YEL
BLK

RED RED
22579

a- Voltage regulator/rectifier
b- Stator
c- Fuse (20 amps)
d- Starter solenoid
e- To starter terminal
f- To battery

NOTE: Readings listed are taken at 20 °C (68 °F) with a digital ohmmeter. Due to the number of different manufacturers of
meters available and temperature variance, test results may vary.
NOTE: It is not necessary to remove the stator for testing.
Battery Charge Windings
1. Disconnect the voltage regulator/rectifier from the stator connector, if equipped.
2. Test the three stator battery charge windings for continuity.

DMT 2004 Digital Multimeter 91‑892647A01

NOTE: The stator is not polarity sensitive when checking ohm resistant values.

a b a b a a - Positive meter lead

b
connection
b - Negative meter lead
connection

9979

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Ignition

Stator Battery Charge Windings Resistance

Meter scale Auto range
Reading (ohms) 0.29–0.43
3. Test each of the stator windings to engine ground. If continuity is found, replace the stator.

Stator Battery Charge Windings Resistance to Ground

Meter scale Auto range
Reading (ohms) Open

Ignition Charge Windings DVA Output Test

a - ECM engine harness connector

b - Stator

WHT/BLK

WHT/RED
WHT

WHT
WHT/BLU
WHT
b

18 1

2 WHT/RED
18 WHT
19 WHT
20 WHT
23 WHT/BLK
24 WHT/BLU

22580

34 17

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 Ignition

1. Disconnect the stator ignition charge connector from the engine wire harness connector.

a - Stator ignition charge connector

a b - Fuse holder
c - ECM

9852

2. Test each of the connector points with a DMT 2004 Digital Multimeter DVA setting.

DMT 2004 Digital Multimeter 91‑892647A01

a- White (ECM charge coil)

c
b- White/blue (ignition mid/low speed coil)
c- White/black (ignition mid/low speed coil)
d- White/red (ignition high speed coil)
e- White (ECM charge coil)
b d
f- White (ECM charge coil)

a e

f
16728

DVA Adapter Meter Test DVA Reading DVA Reading

Meter Setting
Leads During One During Engine DVA Reading
With DVA Meter Range
Pull (Manual Cranking (Electric Engine Running
Red Black Adapter
Start) Start)
DC volts/
a f 400 volt 24 volts 20 volts 16 volts
Record Mode
DC volts/
e f 400 volt 24 volts 20 volts 16 volts
Record Mode
DC volts/
b c 400 volt 38 volts 36 volts 13 volts
Record Mode
DC volts/
d c 400 volt 46 volts 36 volts 218 volts
Record Mode

Flywheel Removal and Installation

Flywheel Removal
1. Remove the timing belt cover and recoil assembly. Refer to Section 8 ‑ Manual Starter.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-11

Ignition

2. Remove the three bolts securing the flywheel cup to the flywheel.

a a - Bolts securing flywheel cup (3)

9783

3. Hold the flywheel in place with a flywheel holder and remove the flywheel nut.

a a - Breaker bar
b - Flywheel holder

9775

Flywheel Holding Tool 91‑52344

4. Install a three point flywheel puller onto the flywheel. Do not use a jaw type puller on the ring gear.
5. Tighten the flywheel puller until the flywheel is loose from the crankshaft.

a - Bolts (3)
b b - Flywheel puller

9782

Flywheel Puller/Lifting Ring 91‑83164M

6. Remove the flywheel.

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 Ignition

7. Inspect the flywheel key for damage. Replace as needed.

9784

Flywheel Installation
1. Install the flywheel key.

9784

2. Align the flywheel keyway with the flywheel key. Install the flywheel onto the crankshaft. Ensure the flywheel is fully seated
on the crankshaft taper.
3. Install the washer and flywheel nut.
4. Use a flywheel holder to secure the flywheel and tighten the flywheel nut to the specified torque.

a - Flywheel holder
b - Torque wrench

b
a

9829

Description Nm lb. in. lb. ft.

Flywheel nut 150 110.5

Flywheel Holding Tool 91‑52344

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Ignition

5. Install the flywheel cup and secure to the flywheel with three bolts. Tighten the flywheel cup bolts to the specified torque.

a a - Bolts securing flywheel cup (3)

9783

Description Nm lb. in. lb. ft.

Flywheel cup bolt 6 53

6. Install the recoil assembly, and the timing belt cover. Refer to Section 8 ‑ Manual Starter.

Stator Removal and Installation

Stator Removal
1. Remove the timing belt cover and recoil assembly. Refer to Section 8 ‑ Manual Starter.
2. Remove the flywheel. Refer to Section 2A ‑ Flywheel Removal and Installation.
3. Cut the cable ties securing the voltage regulator connector, and the ignition charge connector to the engine wire harness.
4. Bend the clamp to remove the stator wires.
5. Unplug the stator ignition charge connector from the engine harness.
6. Unplug the voltage regulator/rectifier connector.

a - Clamp
b - Battery charging connector
c - Voltage regulator/recitifier
c connector
d d - Stator ignition charge connector

9856

7. Remove the three bolts securing the stator assembly to the coil bracket. Remove the stator.

a a - Bolts (3)

10117

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 Ignition

Ignition Stator Installation

1. Install the stator with the stator wires facing towards the front starboard side of the engine.
2. Secure the stator to the coil bracket with three stator bolts. Tighten the bolts to the specified torque.

a a - Bolts (3)

10117

Description Nm lb. in. lb. ft.

Bolt securing stator assembly 6 53

3. Connect the stator ignition charge connector to the engine harness connector.
4. Connect the stator connector to the regulator/rectifier connector.
5. Secure the stator ignition charge connector and the trigger connector to the engine harness with a cable tie.
6. Secure the voltage regulator/rectifier connector to the engine wire harness with a cable tie.
7. Bend the clamp to secure the stator charge and ignition charge wire harness.

a- Clamp
b- Battery charging connector
c- Voltage regulator/rectifier connector
c d- Stator ignition charge connector
d

9856

8. Install the flywheel. Refer to Flywheel Removal and Installation .

9. Install the recoil assembly and timing belt cover. Refer to Section 8 ‑ Manual Starter.

Crank Position Sensor (CPS)

There are two Crank Position Sensors (CPS) on the cylinder block. They are offset 120° from each other. The offset CPS
configuration helps the ECM to determine the crankshaft position and the engine RPM. The CPS is a Hall effect switch. The
Hall effect switch changes when its magnetic field collapses. When the field collapses, an AC voltage pulse is generated. This
AC pulse is sent to the ECM. The timing and frequency of these pulses allows the ECM to regulate the ignition timing, fuel
injector timing, and the fuel injection volume. This type of crankshaft position recognition is extremely accurate, very reliable,
and will not change values with extreme temperature conditions. If the crank position sensors fail, the engine will run rough or
stop running.

Crank Position Sensor Removal and Installation

Starboard Crank Position Sensor Removal
1. Remove the timing belt cover and the recoil assembly. Refer to Section 8 ‑ Manual Starter.
2. Remove the flywheel. Refer to Flywheel Removal and Installation.
3. Cut the cable tie securing the CPS wire connector and the stator harness connector to the engine harness.
4. Disconnect the CPS connector from the engine harness connector.

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Ignition

5. Remove the two bolts securing the CPS to the coil bracket.

a - Bolts securing CPS (2)

b - Cable tie

b
a

16733

Port Crank Position Sensor Removal

1. Remove the bolts securing the CPS to the coil bracket.
2. Disconnect the CPS harness connector from the engine harness connector.
3. Bend the clamp to remove the CPS wire harness.

a - CPS harness connector

b - Bolts securing CPS (2)
a c - CPS ground wire

c
b

16734

Starboard CPS Installation

1. Install the clamp onto one of the CPS mounting bolts.
2. Install the bolt with the clamp on the forward mounting hole of the CPS.
3. Secure the CPS with two bolts. Tighten bolts to the specified torque.
4. Connect the CPS harness connector to the engine harness connector.
5. Secure the CPS wire harness to the engine harness with a cable tie.

a - Bolt with a clamp securing CPS

b - Cable tie

b
a

22300

Page 2A-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

Description Nm lb. in. lb. ft.

Crank position sensor bolt (2) 4 35.5
6. Install the flywheel. Refer to Flywheel Removal And Installation.
7. Install the recoil assembly and timing belt cover. Refer to Section 8 ‑ Manual Starter.

Port CPS Installation

1. Insert a bolt through the CPS ground wire.
2. Secure the CPS with two bolts. Tighten the bolts to the specified torque.
3. Connect the CPS harness connector to the engine harness connector.
4. Secure the CPS wire harness to the engine wire harness with the clamp.

a - CPS harness connector

b - Bolts securing CPS (2)
a c - CPS ground wire

c
b

16734

Description Nm lb. in. lb. ft.

Crank position sensor bolt (2) 4 35.5
5. Install the flywheel. Refer to Flywheel Removal and Installation.
6. Install the recoil assembly and timing belt cover. Refer to Section 8 ‑ Manual Starter.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-17

Ignition

Crank Position Sensor Testing

b
c

BLK

RED/WHT
RED/YEL

BLK
18 1

a
RED/YEL

15 BLK BLK
32 RED/WHT RED/WHT
33 RED/YEL
22578

34 17

a - ECM engine harness connector

b - Port CPS
c - Starboard CPS

NOTE: Reading listed are taken at 20 °C (68 °F) with a digital ohmmeter. Due to the number of different manufactures of
meters available and temperature variance, your test results may vary.
NOTE: It is not necessary to remove the crank position sensors from the powerhead for testing.
Port CPS (Single Wire)
1. Disconnect the CPS connector from the engine wire harness connector.

a - Starter
b - CPS connector
c - Vapor Separator Tank (VST)

c
a
b
9958

2. Connect one of the meter leads to the CPS connector and the other meter lead to engine ground.

DMT 2004 Digital Multimeter 91‑892647A01

3. Replace the CPS if out of specification.

Page 2A-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

NOTE: The CPS is not polarity sensitive.

a - Engine ground
a b - CPS harness connector

b
9960

Meter Test Leads Meter Scale Reading (Ω)

Red Black
CPS wire harness connector Engine ground Auto range 148 ‑ 222

Starboard CPS (Two Wire)

1. Disconnect the CPS connector from the engine wire harness connector.

b a - Crank position sensor wire harness connector

b - Fuse holder
a c - ECM

9962
2. Insert the meter leads into the crank position sensor wire harness connector.

DMT 2004 Digital Multimeter 91‑892647A01

NOTE: The CPS is not polarity sensitive.

9970

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Red/White Black Auto range 148 ‑ 222

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-19

Ignition

Electronic Control Module (ECM)

This electronic control module (ECM) is an alternator driven component. It does not require a 12 volt battery source to function.
As the flywheel is rotated by the recoil rope or with the electric starter, the ignition stator generates voltage to energize the
ECM, ignition coils, and the high pressure fuel pump. The ECM receives information from the CPS, engine temperature sensor,
manifold pressure sensor, oil pressure sensor, air temperature sensor, and calculates the engine rotation position, engine
RPM, ignition timing, fuel injection timing, and fuel injection pulse width (duration). The ECM will also store past running
information and failure codes; and generates a warning horn and warning light during the event of over temperature, insufficient
oil pressure, or a sensor out of parameters.
Engine operating information and stored running history can be monitored and reviewed with the CDS and the harness adapter
that connect between the CDS and the ECM diagnostic port.

CDS G3 Diagnostic Tool Kit 8M0114141

Adapter Harness 84‑899150T01
Adapter Harness 84‑822560A7
Extension Cable 84‑825003A 1

ECM Removal and Installation

ECM Removal
1. Disconnect the engine harness plug from the ECM.
2. Remove the fuse holder from the ECM.
3. Remove the two bolts securing the ECM to the mounting bracket.

a- Engine harness plug

c b- ECM diagnostic access
c- Fuse holder
d- Bolt securing ECM (2)

b d

a
9899

ECM Installation
1. Install and secure the ECM with two bolts. Tighten the bolts to the specified torque.
2. Connect the engine harness connector to the ECM.
3. Install the fuse holder to the ECM.

a- Engine harness plug

c b- ECM diagnostic access
c- Fuse holder
d- Bolt securing ECM (2)

b d

a
9899

Description Nm lb. in. lb. ft.

Bolt securing ECM 6 53

Page 2A-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

Ignition Coils
The primary side of the ignition coil receives voltage discharged from a capacitor located inside the ECM. The voltage is
multiplied significantly by the coil so it can jump the spark plug gap while under compression. The ignition coil will produce a
high voltage spark every revolution of the flywheel. The spark timing curve is controlled by the ECM. The output voltage of the
coil is approximately 40,000 volts.

Ignition Coil Removal and Installation

Ignition Coil Removal
1. Remove the ignition coil high tension lead from the spark plug.
2. Disconnect the ignition coil from the engine wire harness.
3. Remove the bolt securing the ignition coil to the cylinder head.

a - Ignition coil high tension lead

b b - Bolt securing ignition coil
c - Ignition coil connector
a c

9905

Ignition Coil Installation

1. Position the ignition coil with the high tension lead exiting the coil facing towards the lower unit.
2. Place the washer, clamp, and ignition coil ground lead onto the ignition coil mounting bolt.

b c a- Washer
d
a b- Clamp
c- Ignition coil ground lead
d- Ignition coil

9908

3. Secure the ignition coil to the cylinder head with the ignition coil mounting bolt. Tighten the ignition coil mounting bolt to the
specified torque.

Description Nm lb. in. lb. ft.

Ignition coil mounting bolt 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-21

Ignition

4. Connect the ignition coil to the engine harness and secure the ignition coil connector with the clamp.

b a- Ignition coil
c b- Ignition coil mounting bolt
c- Ignition coil connector
a d- Clamp

9930

Ignition Coil Testing

a- ECM engine harness connector

b- Cylinder #1 ignition coil
c- Cylinder #2 ignition coil
b c d d- Cylinder #3 ignition coil

a
18 1
BLK/GRN
BLK/WHT
BLK/RED

25
26
27

22852
34 17
NOTE: Readings listed are taken at 20 °C (68 °F) with a digital ohmmeter. Due to the number of different manufactures of
meters available and temperature variance, test results may vary.
NOTE: It is not necessary to remove the ignition coils from the powerhead for testing.
1. Disconnect the ignition coil from the engine harness connector.

Page 2A-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition
2. Remove the ignition coil high tension lead from the spark plug.

a
b a - Coil high tension lead
b - Ignition coil
c - Ignition coil harness connector
c

9951

3. Check the resistance of the coil primary windings to engine ground. Replace the ignition coil if not within specification.

DMT 2004 Digital Multimeter 91‑892647A01

a a - Engine ground (coil mounting bolt)

b - Coil primary lead

9952

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Coil primary lead Coil mounting bolt Auto range 0.17 ‑ 0.23

4. Hold the high tension lead and rotate the spark plug cap counterclockwise. Remove the spark plug cap from the spark plug
high tension wire.
5. Measure the resistance of the ignition coil secondary winding to engine ground. Replace the ignition coil if not within
specification.

a a - Engine ground (coil mounting bolt)

b - Coil secondary winding (coil high tension lead)

9954

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Coil high tension lead Engine ground Auto range 3.3 ‑ 4.9k

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-23

Ignition
6. Measure the resistance of the spark plug cap. Replace the spark plug cap if not within specifications.

b a - Meter negative lead

a c b - Spark plug cap
c - Meter positive lead

9955

Meter Test Leads Meter Scale Reading (Ω)

Red Black
High tension lead end Spark plug end Auto range 3.0k ‑ 7.0k

7. Reinstall the spark plug cap onto the spark plug high tension lead.

Engine Temperature Coolant Sensor (ETC)

The engine temperature coolant sensor is located on the top of the cylinder block. The ETC sensor monitors the temperature of
the cooling water that has passed through the engine as controlled by the thermostat. The ECM monitors the engine
temperature through the ETC sensor and adjusts the amount of fuel injected into the combustion chamber to achieve optimum
fuel economy based on the engines RPM.
In the event of an over‑temperature exceeding 90 °C (194 °F), the ECM will limit engine power, generate a failure code, and
complete the circuit for the warning horn and low oil pressure lamp; informing the operator of potential engine damage.

ETC Removal and Installation

ETC Removal
1. Remove the recoil assembly and the timing belt cover. Refer to Section 8 ‑ Recoil Starter.
2. Disconnect the engine wire harness connector from the ETC sensor.
3. Unthread the ETC sensor from the cylinder block.

b c a - Fuel cooler
b - ETC sensor
c - Engine wire harness connector

11580

ETC Installation
1. Cover the threads of the ETC sensor with Loctite 567 PST Pipe Sealant.
2. Thread the ETC sensor into the cylinder block. Tighten the ETC sensor to the specified torque.

Page 2A-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

3. Connect the engine wire harness connector to the ETC sensor.

b c a - Fuel cooler
b - ETC
c - Engine wire harness connector

11580

Tube Ref No. Description Where Used Part No.

Loctite 567 PST Pipe
9 ETC threads 92-809822
Sealant

Description Nm lb. in. lb. ft.

ETC 22 195

ETC Sensor Test

a - ECM engine harness connector

b - Engine temperature coolant sensor

18 1 a b

8 GRN/YEL

34 BLK/BLU

22588
34 17
NOTE: A defective (failed) or disconnected engine temperature coolant sensor or manifold absolute pressure sensor will
activate the warning horn and warning light.
1. Place the engine temperature coolant sensor in a container filled with water.
2. Place a thermometer in the water and slowly heat the water.
3. Measure the resistance when the specified temperature is reached. If out of specification, replace the sensor.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-25

Ignition

DMT 2004 Digital Multimeter 91‑892647A01

a - Engine coolant temperature sensor

a

22587

Meter Test Leads Meter Scale Temperature Reading (Ω)

Red Black
20° C (68° F) 2.4 ‑ 2.9
Black/Blue Green/Yellow Auto
80° C (176° F) 0.29 ‑ 0.32

Oil Pressure Sensor

The oil pressure sensor is located on the top port side of the cylinder block. It is a pressure sensitive switch that will show either
continuity or no continuity. In the event that engine oil pressure drops below 24.5 kPa (3.5 psi) for more that 0.5 seconds, the
ECM will limit engine power, generate a failure code, and complete the circuit for the warning horn and low oil pressure lamp;
informing the operator of potential engine damage. The warning system can be reset by stopping the engine.

Oil Pressure Switch Removal and Installation

Oil Pressure Switch Removal
1. Remove the two bolts securing the VST to the cylinder block.
2. Lift the VST up and off the lower mounting grommet. This will allow sufficient clearance to access the oil pressure switch.
Do not lose the washers on the back side of the VST mounting grommets.

b a - Fuel hose
b - High pressure fuel pump wire harness connector
c - Bolt securing the VST (2)
a

11584

3. Slide the oil pressure switch protection boot off the oil pressure switch.

11589

4. Remove the screw securing the engine harness wire to the oil pressure switch.

Page 2A-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

5. Remove the oil pressure switch from the cylinder block.

11590

Oil Pressure Switch Installation

1. Apply Loctite 567 PST Pipe Sealant to the threads of the oil pressure switch.
2. Thread the oil pressure switch into the cylinder block. Tighten the oil pressure switch to the specified torque.
3. Install the engine harness oil pressure switch wire and secure with a screw. Tighten the screw to the specified torque.
4. Coat the oil pressure switch with dielectric grease to prevent corrosion.

11590

Tube Ref No. Description Where Used Part No.

Loctite 567 PST Pipe
9 Oil pressure switch threads 92-809822
Sealant
6 Dielectric Grease Oil pressure switch wire connection 92-823506 1

Description Nm lb. in. lb. ft.

Oil pressure switch 8 71
Screw securing the oil pressure sensor wire 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-27

Ignition

5. Cover the oil pressure switch with the protection boot.

11589

6. Install the VST onto the lower mounting grommet.

7. Secure the VST to the cylinder block with two washers and bolts. Tighten the VST mounting bolts to the specified torque.

b a - Fuel hose
b - High pressure fuel pump wire harness connector
c - Bolt securing the VST (2)
a

11584

Description Nm lb. in. lb. ft.

Bolt securing VST 6 53

Oil Pressure Switch Test

18 1
a - ECM engine harness
connector
b - Oil pressure switch
5 BRN/WHT

a
b

22589
34 17
1. Connect the red lead of an ohm meter to the terminal and the black lead to the oil pressure switch metal body.
2. Using a controllable air pressure source, apply air pressure to the oil pressure switch. Check for continuity specification.

Page 2A-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

DMT 2004 Digital Multimeter 91‑892647A01

3119

Meter Test Leads

Meter Scale Reading (O)
Red Black
Terminal Oil pressure switch metal body Auto 19.3 ‑ 27.5 kPa (2.8 ‑ 4.0 PSI)

Manifold Air Temperature (MAT) Sensor

The manifold intake air temperature sensor is a thermistor that controls a signal voltage to the ECM. It is located near the air
entrance of the throttle body. It informs the ECM of the air temperature before the air enters the intake manifold. The ECM
adjusts the fuel injection duration needed to run the engine at optimum efficiency according to the MAT information. When
intake air is cold, the sensor resistance is high. As the air temperature rises, resistance lowers.

MAT Sensor Removal and Installation

MAT Sensor Removal
1. Remove the two bolts securing the electrical cover. Do not lose the spacers.
2. Remove the electrical cover from the grommets in the intake manifold.

a - Grommets in the intake manifold

b - Bolts securing the electrical cover (2)

a
b

10493

3. Pull the MAT sensor out of the rubber grommet.

4. Remove the engine harness connector from the MAT sensor.

a - MAT sensor

11578

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-29

Ignition

MAT Sensor Installation

1. Connect the engine wire harness connector to the MAT sensor.
2. Push the MAT sensor into the rubber grommet.
3. Ensure the MAT sensor is fully seated in the rubber grommet.

a - MAT sensor

11578

4. Install the electrical cover into the grommets in the intake manifold and secure with two bolts, and spacers. Tighten to the
specified torque.

a - Grommets in the intake manifold

b - Bolts securing the electrical cover (2)

a
b

10493

Description Nm lb. in. lb. ft.

Bolts securing the electrical cover (2) 6 53

Page 2A-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

MAT Sensor Test

a - ECM engine harness connector

b b - Manifold air temperature (MAT) sensor

18 1

GRN/WHT
BLK/BLU
14

34

34 17 22592

Use the CDS to test the MAT sensor. If the MAT sensor reads 5 °C ( 41 °F) ± difference from the ambient air temperature,
replace the MAT sensor. Perform the MAT sensor test when the engine is cold.

MAT Sensor Specifications

20 °C (68 °F) 2.35–2.55 ohms
80 °C (176 °F) 0.3–0.035 ohms

1. Measure the resistance of the MAT sensor.

2. Connect the DMT 2004 Digital Multimeter to the contact pins on the MAT sensor.
3. Compare the resistance shown on the DMT 2004 Digital Multimeter with the MAT sensor specifications. Replace the MAT
sensor if the resistance is out of the specifications.

23015

DMT 2004 Digital Multimeter 91‑892647A01

Manifold Absolute Pressure (MAP) Sensor

The MAP sensor measures the changes in the intake manifold pressure. It is located at the top of the intake manifold. The
signal voltage from the MAP sensor received by the ECM is referenced as the atmosphere barometric pressure. This
information is used by the ECM as an indication of altitude during start up. The MAP will change the signal voltage as a result
of engine load and speed changes. The MAP sensor signal voltage is used by the ECM programed logic to determine the
optimum fuel injection timing, ignition timing, and fuel injection duration.

MAP Sensor Removal and Installation

MAP Sensor Removal
1. Disconnect the engine harness connector from the MAP sensor.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-31

Ignition

2. Remove the bolt securing the MAP sensor to the MAP sensor mounting bracket.

b a - Bolt securing the MAP sensor

a b - Engine harness connector
c - MAP sensor reference hose

20831

3. Lift the MAP sensor off the MAP sensor mounting bracket and remove the MAP sensor reference hose.

20833

MAP Sensor Installation

1. Connect the MAP sensor reference hose to the MAP sensor. Secure the MAP sensor reference hose to the MAP sensor
with a spring clamp.
2. Install the MAP sensor to the MAP sensor mounting bracket.
3. Secure the MAP sensor to the MAP sensor mounting bracket with a bolt. Tighten the bolt to the specified torque.
4. Connect the engine harness connector to the MAP sensor.

Description Nm lb. in. lb. ft.

Bolt 6 53

Page 2A-32 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

MAP Sensor Test

a - ECM engine harness

connector
b - MAP sensor
b

a
18 1

RED/BLU
BLK/BLU
GRN/BLU
13

17
34

34 17 22591

The testing of the MAP sensor when it is not mounted on the engine cannot be performed with accuracy. Use the CDS to check
the functioning of the MAP sensor.
NOTE: A defective (failed) or disconnected engine coolant temperature sensor or manifold absolute pressure sensor will
activate the warning horn and warning light.

Throttle Position Sensor (TPS)

The throttle position sensor (TPS) transmits throttle angle information to the ECM. The ECM uses this information to vary the
injector pulse width and ignition timing accordingly. The TPS is non‑serviceable. Replace the throttle body with the TPS if the
sensor is not within specifications.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-33

Ignition

TPS Test

a - ECM engine harness connector

b - Throttle Position Sensor

a
18 1

RED/BLU

BLU/WHT
BLK/BLU

17

34

34 17 22602

Check the TPS resistance with the throttle body at idle and at WOT. If the TPS is not within the specification, replace the
throttle body and the TPS as an assembly.

DMT 2004 Digital Multimeter 91‑892647A01

a a - Black wire
b c b - Yellow wire
c - Blue wire

22597

Meter Test Leads

Meter Scale Reading (O)
Red Black
c a Auto 4.0 ‑ 6.0 k
Idle 0.4 ‑ 1.0 k
b a Auto
WOT 3.2 ‑ 3.8 k
Idle 3.8 ‑ 4.6 k
b c Auto
WOT 1.2 ‑ 1.6 k

NOTE: The throttle position sensor operation can be measured the the CDS tool.

CDS G3 Diagnostic Tool Kit 8M0114141

Page 2A-34 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Ignition

Tiller Handle Stop Button and Lanyard Stop Switch Test

a a - Lanyard stop switch
b - Stop button
c - ECM engine harness

BLK/YEL

BLK
connector

BLK/YEL

BLK/YEL

BLK
BLK
18 1

3 BRN

BLK
28 BLK

c 23024

34 17
1. Disconnect the black/yellow lanyard stop switch wire from the brown engine harness wire.
2. Disconnect the black stop button wire from the black engine harness wire.

a- Black (lanyard stop switch)

b- Black/yellow (tiller handle stop button)
c- Brown (engine harness)
b d- Black (engine harness)
a c e- Black/yellow (lanyard stop switch)
f- Black (tiller handle stop button)

f e 18096

3. Set the DMT 2004 Digital Multimeter to read ohms on the auto scale.
4. Ensure the lanyard stop switch is in the "RUN" position.
5. Connect the DMT 2004 Digital Multimeter to the black stop button wire, and the black/yellow lanyard stop switch wire. The
meter should show no continuity. If continuity is found, the lanyard stop switch, and the stop button must be tested
separately to determine which component is defective.
6. Set the lanyard stop switch to the "OFF" position. The meter should show continuity. If no continuity is found, the lanyard
stop switch is defective and must be replaced.
7. Set the safety switch to the "RUN" position.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2A-35

Ignition
8. Push on the stop button to activate the stop switch. The meter should show continuity. If no continuity is found, the stop
button is defective and must be replaced.

DMT 2004 Digital Multimeter 91‑892647A01

Page 2A-36 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Electrical
Section 2B - Charging and Starting System
Table of Contents 2
B
Charging and Starting Specifications.................................2B-2 Wire Color Code Abbreviations................................ 2B-18
Electrical Bracket and Cover..............................................2B-4 Regulator/Rectifier Diode Test .................................2B-19
Flywheel, ECU, and Wiring Harness .................................2B-6 Engine Wire Harness (Remote Control) ......................... 2B-20
Starter Motor and Rectifier.................................................2B-8 Engine Wire Harness Removal (Remote Control).... 2B-20
Starter Motor Components...............................................2B-10 Engine Wire Harness Installation (Remote Control)
Battery..............................................................................2B-12 .............................................................................. 2B-24
Battery Cable Test.................................................... 2B-12 Engine Wire Harness (Tiller Handle) .............................. 2B-30
Original Battery Cable Length and Gauge Shipped Engine Wire Harness Removal (Tiller Handle)......... 2B-30
with Engine............................................................2B-12 Engine Wire Harness Installation (Tiller Handle)...... 2B-33
Battery Cable Size for Outboard Models.................. 2B-12 Starter Motor.................................................................... 2B-37
Replacement Parts................................................... 2B-13 Starting System Description..................................... 2B-37
Recommended Battery............................................. 2B-14 Troubleshooting the Starting Circuit......................... 2B-37
Battery Precautions.................................................. 2B-14 Starter Solenoid Test................................................ 2B-37
Charging a Discharged Battery.................................2B-14 Starting System Troubleshooting Chart....................2B-38
Winter Storage of Batteries.......................................2B-14 Starter Motor Removal..............................................2B-39
Battery Charging System................................................. 2B-15 Starter Motor Disassembly....................................... 2B-40
Battery Charging System Description.......................2B-15 Starter Motor Reassembly........................................ 2B-41
Troubleshooting Battery Charging System............... 2B-15 Starter Motor Installation...........................................2B-44
Voltage Regulator/Rectifier Description....................2B-15
Voltage Regulator/Rectifier Removal and Installation
.............................................................................. 2B-15

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-1

Charging and Starting System

Charging and Starting Specifications

Charging and Starting Specifications
Alternator type Three phase
Alternator charge coil resistance 0.29–0.43 ohms
Alternator output at 850 RPM 5.5 A
Alternator output at 5000 RPM 15 A
Starter
Type Bendix
Output 0.6 kW at 12 V
Brush length 12.5 mm (0.49 in.)
Brush length (service limit) 9.5 mm (0.37 in.)
Commutator undercut 0.5–0.8 mm (0.02–0.03 in.)
Commutator diameter 30 mm (1.18 in.)
Commutator diameter (service limit) 29 mm (1.14 in.)
Fuse capacity 20 A
Fuse type Mini fuse
Battery requirements (minimum)
Above 0 °C (32 °F) 465 marine cranking amps (MCA) or 350 cold cranking amps (CCA)
Below 0 °C (32 °F) 1000 marine cranking amps (MCA) or 775 cold cranking amps (CCA)

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Starter end cap bushing
80 SAE Engine Oil 30W Armature shaft Obtain Locally
Starter armature shaft, and helix
95 2-4-C with PTFE Battery terminal bolts 92-802859A 1

Special Tools
DMT 2004 Digital Multimeter 91‑892647A01

Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC

V Hz
H z TEMP
mA
A
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
mV IG
OFF IP

TEMP

A mA COM V Hz

4516

Hose Clamp Tool Kit 91‑803146A2

Aids in the installation of high pressure (Oetiker ®) hose clamps.

5819

Page 2B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-3

Charging and Starting System

Electrical Bracket and Cover

6 3
7
8

2
9
11
9
6
10
7 1

28
23 27
12 25
24
23
22
18 21

17 16 26

19
20

15
14 13

16662

Page 2B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Electrical Bracket and Cover

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Electrical bracket
2 5 Bolt 6 53
3 1 Starter solenoid
4 1 Trim up relay
5 1 Trim down relay
6 4 Boot
7 2 Trim relay power cable
8 2 Trim relay ground cable
9 2 Bolt 6 53
10 1 Electrical cover
11 2 Bushing
12 2 Bolt (M6 x 20) 6 53
13 1 Support bracket
14 1 Wire connector retainer
15 3 Bolt 6 53
16 1 Warning Horn (tiller handle only)
17 1 MAT sensor
18 1 Grommet
19 1 Hose
20 1 Hose
21 1 IAC
22 3 Bolt 6 53
23 6 Washer
24 3 Bushing
25 3 Rubber mount
26 1 Plate
27 1 Washer
28 1 Nut (M6)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-5

Charging and Starting System

Flywheel, ECU, and Wiring Harness

2
3
27 28
1

6 5

11 4
10
29
9
8 11
7

12

20 26
21 18
23
22
24 25

14 16
13

15
17 22
19

20518

Page 2B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Flywheel, ECU, and Wiring Harness

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Flywheel
2 1 Flywheel nut 150 110.6
3 1 Washer
4 1 Stator
5 3 Bolt 6 53
6 3 Clamp
7 1 Plug
8 1 Coil bracket
9 3 Bolt 6 53
10 1 Trigger
11 4 Screw 6 53
12 1 Trigger
13 3 Ignition coil
14 3 Boot
15 3 Bolt 6 53
16 2 Clamp
17 1 ECU
18 1 Plug
19 1 ECU bracket
20 2 Bolt 6 53
21 2 Washer
22 6 Washer
23 3 Bolt 6 53
24 3 Spacer
25 3 Rubber mount
26 3 Terminal plug
27 1 ECU harness
28 4 Cable tie
29 1 Clamp

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Charging and Starting System

Starter Motor and Rectifier

31
18 25 32
24
33
26 29 30
17
23 27
21
26 28

20 21
22
19
16
14

1
15
13

2
11 12
10

4 3

9 7

34

17115

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 Charging and Starting System

Starter Motor and Rectifier

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Starter motor
2 1 Rubber mount
3 1 Bracket
4 2 Bolt 13 115
5 1 Battery cable
6 1 Bolt 6 53
7 1 Neutral start safety switch (tiller handle electric start only)
8 1 Actuator
9 1 Warning light
10 1 Boot
11 1 Boot (Red)
12 1 Cable
13 1 Boot (Red)
14 1 Switch
15 1 Cable
16 1 Power trim extension harness
17 1 Regulator/Rectifier
18 2 Bolt 6 53
19 1 Plate
20 2 Bolt 6 53
21 4 Washer
22 2 Spacer
23 2 Rubber mount
24 1 MAP sensor
25 1 Screw (M6 x 16) 6 53
26 2 Clip
27 1 Hose
28 1 Water temperature sensor 22 194.7
29 1 O‑ring
30 1 Fuse harness
31 1 Fuse (20 ampere)
32 1 Terminal plug
33 2 Bolt 6 53
34 1 Start switch

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Charging and Starting System

Starter Motor Components

3
5
4

8
9 14
7
11 13
10
12

16663

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 Charging and Starting System

Starter Motor Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Starter motor
2 1 Pinion
3 1 Washer
4 1 Brush holder
5 2 Screw 4 35
6 1 Bushing
7 1 O‑ring
8 1 Bushing
9 1 Washer
10 2 Lockwasher
11 2 Nut 10 88.5
12 2 Bolt 4 35
13 2 Lockwasher
14 2 Washer

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Charging and Starting System

Battery
Battery Cable Test
This test is used to determine if there is excessive resistance in the battery's positive or negative cables, or if the cable is sized
properly to carry the necessary current needed to crank the engine at the proper RPM.
IMPORTANT: This test must be performed while the key switch is in the "START" position. Ignore any voltage readings taken
without the circuit under load.

! WARNING
Moving parts can cause serious injury or death. Wear eye protection and keep hands, hair, and clothing away from moving
parts when performing tests or checking adjustments on an operating engine.

1. Perform a load test on the battery following the instructions supplied with the load tester. Ensure that the battery is brought
to a full charge after being tested.
2. With the key switch in the "START" position, measure the voltage across the battery posts not the cable clamps. Record
the voltage reading. If the voltage is less than 10 VDC, replace the battery.
NOTE: The voltage reading in step 2 is the base voltage. The base voltage reading will be compared to the voltage
readings obtained in the following steps.
3. With the key switch in the "START" position, measure the voltage from the battery positive post (not the cable clamp) to the
starter solenoid (the bolt where the battery positive cable is connected). Record the voltage reading.
4. With the key switch in the "START" position, measure the voltage from the starter motor positive terminal to the battery
negative post (not the cable clamp). Record the voltage reading.
5. If the voltage reading in step 3 was more than 1.0 VDC:
a. Check the cable connections for tightness and corrosion.
b. If the cable is tight and not corroded, replace the cable with a larger diameter cable.
6. If the voltage reading in step 4 was more than 1.0 VDC:
a. Check the cable connections for tightness and corrosion.
b. If the cable is tight and not corroded, replace the cable with a larger diameter cable.
Resistance in the cables can cause a voltage drop and limit current to the starter. If corrosion is present, or if the starter is
worn, there may not be enough amperage to turn the starter motor.
NOTE: If the voltage at the starter is less than 11 VDC, the engine may not start.

Original Battery Cable Length and Gauge Shipped with Engine

Original Equipment Battery Cable Length/Wire Gauge Size Shipped with Engine
Models (HP) Cable Length Wire Gauge Size
6–25 (2 and 4‑Stroke 400 cc [24.4 in³] or less) 2.4 m (8 ft) 8
25–115 (except OptiMax) 2.4 m (8 ft) 6
125–250 (except OptiMax) 3.0 m (10 ft) 6
OptiMax/Verado 3.7 m (12 ft) 4
75/80/90/100/115 EFI FourStroke (2006 and newer) 3.7 m (12 ft) 4

Battery Cable Size for Outboard Models

IMPORTANT: Only use copper battery cables. Do not use aluminum cables for any outboard marine installations.
• If longer battery cables are required, the wire gauge size must increase. See chart following for correct wire gauge size.

a a - Wire gauge size

b - Battery cable length

b
2758

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 Charging and Starting System

Copper Battery Cable Wire Gauge Size

Wire Gauge Size Number SAE
6–25 hp (2 and OptiMax, Verado, 75–115
25–115 hp (except 125–250 hp (except
Models 4‑Stroke 400 cc EFI FourStroke (2006
OptiMax) OptiMax)
[24.4 in³] or less) and newer)
2.4 m (8 ft) 8 6 ‑ ‑
2.7 m (9 ft) 6 4 ‑ ‑
3.0 m (10 ft) 6 4 6 ‑
3.4 m (11 ft) 6 4 4 ‑
3.7 m (12 ft) 6 4 4 4
4.0 m (13 ft) 6 2 4 2
4.3 m (14 ft) 4 2 4 2
4.6 m (15 ft) 4 2 4 2
4.9 m (16 ft) 4 2 2 2
5.2 m (17 ft) 4 2 2 2
5.5 m (18 ft) 4 2 2 2
5.8 m (19 ft) 4 2 2 2
6.1 m (20 ft) 4 2 2 2
6.4 m (21 ft) 2 1 2 1
6.7 m (22 ft) 2 1 2 1
7.0 m (23 ft) 2 1 2 1
Cable Length 7.3 m (24 ft) 2 1 2 1
7.6 m (25 ft) 2 1 2 1
7.9 m (26 ft) 2 1/0 1 1/0
8.2 m (27 ft) 2 1/0 1 1/0
8.5 m (28 ft) 2 1/0 1 1/0
8.8 m (29 ft) 2 1/0 1 1/0
9.1 m (30 ft) 2 1/0 1 1/0
9.4 m (31 ft) 2 1/0 1 1/0
9.8 m (32 ft) 2 1/0 1 1/0
10.1 m (33 ft) 2 2/0 1/0 2/0
10.4 m (34 ft) 2 2/0 1/0 2/0
10.7 m (35 ft) 1 2/0 1/0 2/0
11.0 m (36 ft) 1 2/0 1/0 2/0
11.3 m (37 ft) 1 2/0 1/0 2/0
11.6 m (38 ft) 1 2/0 1/0 2/0
11.9 m (39 ft) 1 2/0 1/0 2/0
12.2 m (40 ft) 1 2/0 1/0 2/0

Replacement Parts
! WARNING
Avoid fire or explosion hazard. Electrical, ignition, and fuel system components on Mercury Marine products comply with
federal and international standards to minimize risk of fire or explosion. Do not use replacement electrical or fuel system
components that do not comply with these standards. When servicing the electrical and fuel systems, properly install and
tighten all components.

IMPORTANT: Deep‑cycle batteries are not suitable for use as engine starting batteries or for use as accessory batteries that
are connected to high output engine charging systems. Deep‑cycle battery life may be shortened by high output engine
charging systems. Refer to individual battery manufacturer instructions for specific battery charging procedures and
applications.

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Charging and Starting System

Recommended Battery
A 12 volt battery with a minimum rating of 465 marine cranking amps (MCA) or 350 cold cranking amps (CCA) is
recommended. For operation below 0 °C (32 °F), a rating of 1000 marine cranking amps (MCA) or 775 cold cranking amps
(CCA) is recommended.

Battery Precautions
! WARNING
An operating or charging battery produces gas that can ignite and explode, spraying out sulfuric acid, which can cause
severe burns. Ventilate the area around the battery and wear protective equipment when handling or servicing batteries.

When charging batteries, an explosive gas mixture forms in each cell. Part of this gas escapes through holes in the vent plugs
and may form an explosive atmosphere around the battery if ventilation is poor. This explosive gas may remain in or around the
battery for several hours after it has been charged. Sparks or flames can ignite this gas and cause an internal explosion, which
may shatter the battery.
The following precautions should be observed to prevent an explosion:
1. Do not smoke near batteries being charged or which have been charged very recently.
2. Do not break live circuits at terminals of batteries, because a spark usually occurs at the point where a live circuit is broken.
Always be careful when connecting or disconnecting cable clamps on chargers. Poor connections are a common cause of
electrical arcs which cause explosions.
3. Do not reverse polarity of battery terminal to cable connections.

Charging a Discharged Battery

! WARNING
An operating or charging battery produces gas that can ignite and explode, spraying out sulfuric acid, which can cause
severe burns. Ventilate the area around the battery and wear protective equipment when handling or servicing batteries.

The following basic rules apply to any battery charging situation:

1. Any battery may be charged at any rate (in amperes), or as long as spewing of electrolyte (from violent gassing) does not
occur, and for as long as electrolyte temperature does not exceed 52 °C (125 °F). If spewing of electrolyte occurs, or if
electrolyte temperature exceeds 52 °C (125 °F), charging rate (in amperes) must be reduced or temporarily halted to avoid
damage to the battery.
2. Battery is fully charged when, over a 2 hour period at a low charging rate (in amperes), all cells are gassing freely (not
spewing liquid electrolyte), and no change in specific gravity occurs. Full charge specific gravity is 1.260–1.275, corrected
for electrolyte temperature with electrolyte level at 4.8 mm (3/16 in.) over plate, unless electrolyte loss has occurred (from
age or overfilling), in which case, specific gravity reading will be lower. For most satisfactory charging, lower charging rates
in amperes are recommended.
3. If, after prolonged charging, specific gravity of at least 1.230 on all cells cannot be reached, battery is not in optimum
condition and will not provide optimum performance; however, it may continue to provide additional service, if it has
performed satisfactorily in the past.
4. To check the battery voltage while cranking the engine with an electric starting motor at ambient air temperature of 23.8 °C
(75 °F), place the red (+) lead of the tester on the positive (+) battery terminal and the black (–) lead of the tester on the
negative (–) battery terminal. If the voltage drops below 10‑1/2 volts while cranking, the battery is weak and should be
recharged or replaced.

Winter Storage of Batteries

Battery companies are not responsible for battery damage, either in winter storage or in dealer stock, if the following
instructions are not observed:
1. Remove battery from its installation as soon as possible and remove all grease, sulfate, and dirt from the top surface by
running water over top of the battery. Be sure, however, the vent caps are tight beforehand and blow off all excess water
thoroughly with compressed air. Check water level, making sure the plates are covered.
2. When adding distilled water to the battery, be extremely careful not to fill more than 4.8 mm (3/16 in.) above perforated
baffles inside the battery. Battery solution or electrolyte expands from heat caused by charging. Overfilling the battery will
cause the electrolyte to overflow (if filled beyond 4.8 mm [3/16 in.] above baffles).
3. Grease terminal bolts with 2‑4‑C with PTFE and store the battery in a cool‑dry place. Remove the battery from storage
every 30–45 days, check the water level, and put on charge for 5 or 6 amps. Do not fast charge.

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 Charging and Starting System

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Battery terminal bolts 92-802859A 1
4. If specific gravity drops below 1.240, check battery for reason and recharge. When gravity reaches 1.260, discontinue
charging. To check specific gravity, use a hydrometer, which can be purchased locally.
5. Repeat preceding charging procedure every 30–45 days, as long as the battery is in storage, for best possible
maintenance during inactive periods to ensure a good serviceable battery in spring. When ready to place the battery back
in service, remove excess grease from the terminals (a small amount is desirable on terminals at all times), recharge
again, as necessary, and reinstall the battery.

Battery Charging System

Battery Charging System Description
The battery charging system components are the flywheel, stator, regulator/rectifier, and the battery. Alternating current (A.C.)
is generated in the stator assembly and flows to the regulator/rectifier which changes the A.C. to a regulated direct current
(D.C.) for charging the battery.

Troubleshooting Battery Charging System

IMPORTANT: The charging system may be damaged by:
• Reversed battery cables
• Running the engine with the battery cables disconnected and stator leads connected to the rectifier
• An open circuit, such as a broken wire or loose connection
A fault in the battery charging system usually will cause the battery to become undercharged. Check the battery electrolyte
level and charge battery.
If the battery will not accept a satisfactory charge, replace the battery.
If the battery accepts a satisfactory charge, determine the cause of the charging system problem as follows.
• Check for correct battery polarity: red cable to positive (+) battery terminal. If the polarity was incorrect, check for a
damaged rectifier and/or main fuse. Refer to Regulator/Rectifier Diode Test.
• Check for loose or corroded battery connections.
• Visually inspect the wiring between the stator and the battery for cuts, chafing, loose, corroded, or disconnected
connection.
• Excessive electrical load from too many accessories will cause battery to run down.

Voltage Regulator/Rectifier Description

The voltage regulator is an electronic device that regulates alternator output according to the accessory loads and state of the
battery. The voltage regulator manages the alternator output according to operating conditions. The voltage regulator must
balance the needs of a fully charged battery, long battery life, and accessory loads.
The voltage regulator has a voltage sensing lead that is connected to a direct battery voltage source. The sensing lead allows
the voltage regulator to monitor and regulate the amount of input voltage and amperage needed to maintain the battery state of
charge.
Symptoms of a faulty voltage regulator may include a discharged battery, short battery life, poor accessory and lighting
operation, frequent bulb replacement, lower than normal voltmeter readings, or frequent topping off of the battery's electrolyte.

Voltage Regulator/Rectifier Removal and Installation

Voltage Regulator/Rectifier Removal

! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

1. Cut the cable tie securing the voltage regulator/rectifier stator connector to the engine harness. Disconnect the voltage
regulator/rectifier harness connector.

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Charging and Starting System

2. Remove the two bolts securing the MAP sensor bracket to the intake manifold.

a - Cable tie securing the voltage regulator/rectifier stator connector

b - Bolts securing the MAP sensor bracket (2)

20821

3. Cut the cable ties securing the voltage regulator/rectifier sensing lead connector to the engine harness. Disconnect the
sensing lead connector.

b c a - MAP sensor
b - Voltage regulator/rectifier connector
c - Cable ties securing the voltage regulator/
rectifier sensing lead connector

a
20822

4. Remove the two bolts securing the voltage regulator/rectifier to the intake manifold. Remove the voltage regulator/rectifier.

a - Voltage regulator/rectifier ground wire

b b - Bolts securing the voltage regulator/rectifier (2)

a
20823

Voltage Regulator/Rectifier Installation

1. Install the voltage regulator/rectifier ground wire eyelet onto one of the voltage regulator/rectifier mounting bolts.
2. Install the bolt with the ground wire eyelet into the lower mounting hole of the voltage regulator/rectifier.
3. Secure the voltage regulator/rectifier to the intake manifold. Do not tighten the bolt at this time.
4. Install a bolt in the upper mounting hole of the voltage regulator/rectifier mounting hole and secure to the intake manifold.

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 Charging and Starting System

5. Tighten the bolts to the specified torque.

a - Voltage regulator/rectifier ground wire

b b - Bolts securing the voltage regulator/rectifier (2)

a
20823

Description Nm lb. in. lb. ft.

Voltage regulator/rectifier bolt (2) 6 53

6. Guide the voltage regulator/rectifier sensing lead connector and the stator connector behind the fuse wires and the engine
wire harness.

20829

7. Connect the voltage regulator/rectifier sensing lead connector to the engine harness connector. Secure the voltage
regulator/rectifier sensing lead connector to the engine harness with two cable ties.

b c a - MAP sensor
b - Voltage regulator/rectifier connector
c - Cable ties securing the voltage regulator/
rectifier sensing lead connector (2)

a
20822

8. Connect the voltage regulator/rectifier stator connector to the stator connector. Secure the voltage regulator/rectifier stator
connector to the engine harness with a cable tie.

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Charging and Starting System

9. Secure the MAP sensor bracket to the intake manifold with two bolts and washers. Tighten the bolts to the specified
torque.

a - Cable tie securing the voltage regulator/rectifier stator connector

b - Bolts securing the MAP sensor bracket (2)

20821

Description Nm lb. in. lb. ft.

Bolts (2) 6 53

Wire Color Code Abbreviations

Wire Color Abbreviations
BLK Black BLU Blue
BRN Brown GRY or GRA Gray
GRN Green ORN or ORG Orange
PNK Pink PPL or PUR Purple
RED Red TAN Tan
WHT White YEL Yellow
LT or LIT Light DK or DRK Dark

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 Charging and Starting System

Regulator/Rectifier Diode Test

d f

RED
GRN
BLK
BLK

BLK
e

RED
RED
YEL
YEL
YEL

RED
a RED
YEL
YEL

YEL
BLK

RED RED
22579

a- Voltage regulator/rectifier
b- Stator
c- Fuse (20 amps)
d- Starter solenoid
e- To starter terminal
f- To battery

The voltage regulator/rectifier can be checked while installed on the engine. The following tests are only standard values and
are difficult to obtain accurately. Due to variables in temperature and the meter manufacture, test values may vary.

DMT 2004 Digital Multimeter 91‑892647A01

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Charging and Starting System

Meter Test Leads Meter Scale

Reading

Red Black

Yellow Ouch

Black Ouch
Red
Yellow Ouch

Yellow Ouch

Red 0.4–0.8

Black 1.0–1.7
Yellow*
Yellow 1.6–1.9

Yellow 1.6–1.9

Red 0.8–1.3

Yellow 0.4–0.8
Black
Yellow 0.4–0.8

Yellow 0.4–0.8

NOTE: * Each yellow lead must be tested.

Engine Wire Harness (Remote Control)

Engine Wire Harness Removal (Remote Control)
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

1. Disconnect both of the battery cables from the battery.

2. Remove the timing belt cover and the recoil assembly. Refer to Section 8A ‑ Manual Starter.
3. Remove the two bolts and spacers securing the wire cover.
4. Pull the wire cover from the grommets in the intake manifold.

a - Grommets in the intake manifold

b - Bolts and spacers securing the wire cover
(2 each)

a
b

10493

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 Charging and Starting System
5. Disconnect the fuel injector harness connectors from the three fuel injectors.

a - Fuel injector harness connectors

b - ECM

b
a

10451

6. Disconnect the engine harness from the ECM.

7. Cut the cable tie securing the trigger connector and the ignition charge harness connector to the engine harness.
8. Disconnect the trigger connector and the ignition charge harness connector.
9. Cut the cable tie securing the voltage regulator stator connector to the engine harness. Disconnect the voltage regulator
stator connector.
10. Lift the fuse holder up to remove the fuse holder from its mounting bracket.
11. Cut the two cable ties securing the voltage regulator sensing lead connector to the engine harness. Disconnect the voltage
regulator sensing lead connector.
12. Disconnect the harness connector from the MAP sensor.

d e a - Ignition charge harness

connector
b - Trigger connector
c c - Fuse holder
d - Voltage regulator stator
connector
e - Voltage regulator
sensing lead connector
b f - MAP sensor harness
connector
f

a
10456

13. Disconnect the water temperature sensor harness connector.

14. Disconnect the trim extension harness connector from the cowl mounted trim switch connector.

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Charging and Starting System
15. Disconnect the ignition coil harness connectors from the ignition coils.

b a - Water temperature sensor harness

connector
b - Trim extension harness connector
c - Ignition coil harness connector (3)
a

10463

16. Remove the bolt securing the air vent assembly to the cylinder block.
17. Remove the bolt securing the fuel cooler mounting bracket to the cylinder block.

a a- Air vent assembly

c b- Fuel cooler
c- Bolt securing the air vent assembly to the cylinder block
d- Bolt securing the fuel cooler mounting bracket to the
cylinder block
b

d
21192

18. Cut the cable tie securing the air vent assembly vent hose to the engine harness.
19. Disconnect the high pressure fuel pump harness connector from the VST.
20. Bend the clamp to access the trigger harness connector and the oil sender harness connector.
21. Disconnect the trigger harness connector and the oil pressure sender harness connector.
22. Pull the engine harness clear from the port side of the engine.

a- Cable tie securing the air vent assembly vent hose

b- High pressure fuel pump harness connector
c- Clamp
d- Trigger harness connector
e- Oil pressure sender harness connector

d
a
b
c
10468

23. Remove the engine harness from the clamp.

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 Charging and Starting System
24. Remove the battery positive cable from the starter solenoid.
25. Remove the fuse wire terminal and the trim solenoid power wire terminal from the battery positive cable protection boot.
26. Remove the bolt securing the battery negative cable, and engine harness ground to the starter.
27. Remove the starter motor cable from the starter solenoid.

a a - Clamp securing the engine harness

d
b - Negative battery cable
c - Positive battery cable, fuse wire terminal, trim
solenoid power wire terminal
d - Starter motor cable
b
c

10480

28. Disconnect the TPS harness connector.

29. Disconnect the low oil pressure light connector (LT green).
30. Disconnect the low oil pressure light connector (white/red).
31. Disconnect the two red wire connectors.
32. Disconnect the starter relay exciter wire connector (green).

d a- TPS harness connector

b- Low oil pressure light connector (LT green)
c- Low oil pressure light connector (white/red)
d- Red wire connectors (2)
a
e- Starter relay exciter wire connector (green)

b
e

c
10488

33. Remove the wire connector retainer.

34. Disconnect the trim harness connector.
35. Disconnect the trim up solenoid wire connector (blue).
36. Disconnect the trim down solenoid wire connector (pink).

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Charging and Starting System
37. Disconnect the Manifold Air Sensor (MAT) sensor from the engine wire harness and remove the MAT sensor.

a- Trim harness connector

b- MAT sensor
c- Trim up solenoid wire connector (blue)
d- Trim down solenoid wire connector (pink)

d
a

b c

10568

38. Disconnect the Idle Air Control (IAC) harness connector from the IAC.

a - IAC
b b - IAC harness connector

10571

Engine Wire Harness Installation (Remote Control)

NOTE: Refer to the wire harness connection diagram located on the back side of the electrical cover for all wire harness
connections.

21199

1. Orientate the engine harness so the 14 pin connector is pointing towards the rear starboard side of the engine.

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 Charging and Starting System
2. Connect the IAC engine harness connector to the IAC.

a - IAC
b b - IAC harness connector

10571

3. Connect engine harness MAT sensor connector to the MAT sensor. Push the MAT sensor into the rubber grommet located
on the electrical bracket
4. Connect the pink wire engine harness connector to the pink wire connector on the trim down solenoid and snap the
connection into the electrical bracket.
5. Connect the blue wire engine harness connector to the blue wire connector on the trim up solenoid and snap the
connection into the electrical bracket.
6. Connect the trim harness extension to the engine harness connector and snap the connection into the electrical bracket.
7. Orientate the trim harness extension to the top port side of the engine, towards the ignition coils.

a- Engine harness connector

b- MAT sensor
c- Trim up solenoid wire connector (blue)
d- Trim down solenoid wire connector (pink)
e- Trim harness extension
e

a
d
b c

20887

8. Install the wire connector retainer.

9. Connect the engine harness two red wire connectors (one male, one female) to the two red connectors on the trim harness
extension.
10. Connect the white/red engine harness low oil pressure wire connector to the white/red low oil pressure light wire connector.
Install the connector into the wire connector retainer.
11. Connect the LT green engine harness low oil pressure wire connector to the LT green low oil pressure light wire connector.
Install the connector into the wire connector retainer.
12. Connect the engine harness Throttle Position Sensor (TPS) connector to the TPS. Snap the TPS connector into the wire
connector retainer.
13. Connect the engine harness green wire connector to the green starter relay exciter wire connector. Install the green
connector into the wire connector retainer.

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Charging and Starting System
14. Install the plugged black wire and the plugged brown wire connectors into the wire connector retainer.

a - Plugged brown wire (ignition stop

a f tiller handle)
b - TPS connector
c - Plugged black wire
b d - Low oil pressure wire (LT green)
e - Low oil pressure wire (white/red)
f - Two red wire connectors (one male,
one female)
c
g g - Starter relay exciter wire (green)
h - Positive battery cable

d
h

e
20889

15. Install the starter cable to the starter solenoid. Protect the starter cable connection with the rubber boot.
16. Push the fuse power wire terminal and the power trim solenoid power wire terminal, through the battery positive cable
protection boot.

b a - Battery positive
b - Fused power wire
c - Trim solenoid power wire
a

20892

17. Secure the positive battery cable, fused power wire, and the trim solenoid power wire to the starter solenoid with a bolt and
washer. Tighten the bolt to the specified torque.
18. Secure the negative battery cable and the engine harness ground wire to the starter with a bolt and washer. Tighten the
bolt to the specified torque.

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 Charging and Starting System
19. Secure the engine harness with the clamp.

a a - Clamp securing the engine harness

d
b - Negative battery cable and engine harness
ground wire
c - Positive battery cable, fuse power wire, trim
solenoid power wire
b d - Starter cable
c

10480

Description Nm lb. in. lb. ft.

Bolt (battery positive and negative cables) 6 53

20. Route the engine harness on the port side of the engine.
21. Connect the trigger harness connector to the engine harness.
22. Connect the oil pressure sender harness connector to the engine harness.
23. Connect the engine harness high pressure fuel pump connector to the VST.
24. Bend the clamp to secure the trigger harness connector and the oil sender harness connector.
25. Use a cable tie to secure the air vent assembly vent hose to the engine harness. Do not collapse the air vent assembly
hose with the cable tie.

a- Cable tie securing the air vent assembly vent hose

b- High pressure fuel pump harness connector
c- Clamp
d- Trigger harness connector
e- Oil pressure sender harness connector

d
a
b
c
10468

26. Install the fuel cooler mounting bracket to the cylinder block and secure with a boLT Do not tighten the bolt at this time.
27. Install the air vent assembly to the top of the fuel cooler mounting bracket.

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Charging and Starting System
28. Tighten the bolt securing the fuel cooler mounting bracket, and the bolt securing the air vent assembly to the cylinder block,
to the specified torque.

a a- Air vent assembly

c b- Fuel cooler
c- Bolt securing the air vent assembly to the cylinder block
d- Bolt securing the fuel cooler mounting bracket to the
cylinder block
b

d
21192

Description Nm lb. in. lb. ft.

Bolt (2) 6 53

29. Connect the water temperature sensor harness connector to the water temperature sensor.
30. Connect the trim harness extension to the cowl mounted trim switch harness connector.
31. Connect the ignition coil harness connectors to the three ignition coils.

b a - Water temperature sensor harness

connector
b - Trim extension harness connector
c - Ignition coil harness connector (3)
a

10463

32. Connect the engine harness to the ECM. Secure the engine harness with a clamp.
33. Connect the trigger harness connector to the engine harness.
34. Connect the engine harness to the ignition charge connector.
35. Secure the trigger connector and the ignition charge harness connector to the engine harness with a cable tie.
36. Connect the voltage regulator stator connector to the engine harness and secure with a cable tie.
37. Install the fuse holder onto the mounting bracket.
38. Connect the voltage regulator sensing lead connector to the engine harness. Secure the voltage regulator sensing lead
connector to the engine harness with two cable ties.

Page 2B-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
39. Connect the engine harness connector to the MAP sensor.

d e a - Ignition charge harness

connector
b - Trigger connector
c c - Fuse holder
d - Voltage regulator stator
connector
e - Voltage regulator
sensing lead connector
b f - MAP sensor harness
connector
f

a
10456

40. Connect the fuel injector harness connectors to the three fuel injectors.

a - Fuel injector harness connectors

b - ECM

b
a

10451

41. Insert the electrical cover into the grommets on the intake manifold.
42. Secure the electrical cover with two bolts, washers, and spacers. Tighten the bolts to the specified torque.
43. Install the recoil assembly and the timing belt cover. Refer to Section 8A ‑ Manual Starter.

a - Grommets in the intake manifold

b - Bolts securing the wire cover (2)

a
b

10493

Description Nm lb. in. lb. ft.

Bolts (2) 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-29

Charging and Starting System

Engine Wire Harness (Tiller Handle)

Engine Wire Harness Removal (Tiller Handle)
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

1. Remove the timing belt cover and the recoil assembly. Refer to Section 8A ‑ Manual Starter.
2. Remove the two bolts and spacers securing the wire cover.
3. Pull the electrical cover from the grommets in the intake manifold.

a - Grommets in the intake manifold

b - Bolts securing the electrical cover (2)

a
b

10493

4. Disconnect the fuel injector harness connectors from the three fuel injectors.
5. Disconnect the ECU harness connector from the ECU.

a - Fuel injector harness connectors (3)

b - ECU harness connector

b
a

21186

6. Cut the three cable ties securing the ignition charge connector, trigger, and the alternator connector to the engine wire
harness.
7. Disconnect the ignition charge connector.
8. Disconnect the trigger connector.

Page 2B-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
9. Disconnect the MAP sensor harness connector.

b c

e d
a 21187

a- Cable ties (3)

b- Ignition charge connector
c- Trigger connector
d- MAP sensor connector
e- Alternator connector

10. Disconnect the ignition coil harness connectors from the ignition coils.
11. Disconnect the water temperature sensor harness connector.

a - Water temperature sensor harness connector

a b - Ignition coil harness connectors (3)

21189

12. Remove the bolt securing the air vent assembly to the cylinder block.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-31

Charging and Starting System
13. Remove the bolt securing the fuel cooler mounting bracket to the cylinder block.

a a- Air vent assembly

c b- Fuel cooler
c- Bolt securing the air vent assembly to the cylinder block
d- Bolt securing the fuel cooler mounting bracket to the
cylinder block
b

d
21192

14. Disconnect the high pressure fuel pump connector from the VST.
15. Open the clamp securing the engine harness and connectors.
16. Disconnect the oil pressure sensor connector.
17. Disconnect the trigger harness connector.

a - High pressure fuel pump

d connector
b - Harness clamp
c - Trigger harness
c connector (red/yellow)
d - Oil pressure sensor
connector (brown/white)

a
21195

18. Disconnect the TPS harness connector.

19. Disconnect the MAT sensor harness connector.
20. Remove the bolt securing the engine harness ground wire to the bracket.

b a - TPS harness connector

b - MAT sensor harness connector
c - Bolt securing the engine harness ground wire
c

21196

21. Disconnect the low oil pressure warning lamp bullet connectors.

Page 2B-32 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
22. Disconnect all of the ignition stop and lanyard stop switch bullet connectors.
23. Disconnect the warning horn connector.
24. Disconnect the IAC connector from the IAC.

c a - Low oil pressure warning lamp bullet connectors (white/

red, LT green)
b - Ignition stop and lanyard stop switch bullet connectors
(black, black/yellow, brown)
d c - Warning horn
d - Warning horn connector
b e - IAC connector

a
21197

Engine Wire Harness Installation (Tiller Handle)

NOTE: Refer to the wire harness connection diagram located on the back side of the electrical cover for all wire harness
connections.

21199

1. Connect the IAC connector to the IAC.

2. Connect the warning horn connector to the warning horn.
3. Connect all of the ignition stop and lanyard stop switch bullet connectors.
4. Connect the low oil pressure warning lamp bullet connectors.

c a - Low oil pressure warning lamp bullet connectors (white/

red, LT green)
b - Ignition stop and lanyard stop switch bullet connectors
(black, black/yellow, brown)
d c - Warning horn
d - Warning horn connector
b e - IAC connector

a
21197

5. Secure the engine wire harness ground wire to the bracket with a bolt. Tighten the bolt to the specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-33

Charging and Starting System
6. Connect the MAT sensor harness connector to the MAT sensor.
7. Connect the TPS harness connector to the TPS.

b a - TPS harness connector

b - MAT sensor harness connector
c - Bolt securing the engine harness ground wire
c

21196

Description Nm lb. in. lb. ft.

Bolt 6 53

8. Connect the engine harness trigger connector to the trigger.

9. Connect the engine harness oil pressure sensor connector to the oil pressure sensor.
10. Secure the engine harness and connectors with the clamp. Close the clamp around the wire harness and connectors.
11. With the wire harness behind the air vent assembly hoses, connect the engine harness to the VST high pressure fuel
pump.

a - High pressure fuel pump

d connector
b - Harness clamp
c - Trigger harness
c connector
d - Oil pressure sensor
connector

a
21195

12. Install the fuel cooler mounting bracket to the cylinder block and secure with a bolt. Do not tighten the bolt at this time.
13. Install the air vent assembly to the top of the fuel cooler mounting bracket and secure with a bolt.

Page 2B-34 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
14. Tighten the bolt securing the fuel cooler mounting bracket and the bolt securing the air vent assembly to the cylinder block
to the specified torque.

a a- Air vent assembly

c b- Fuel cooler
c- Bolt securing the air vent assembly to the cylinder block
d- Bolt securing the fuel cooler mounting bracket to the
cylinder block
b

d
21192

Description Nm lb. in. lb. ft.

Bolt (2) 6 53

15. Connect the engine harness water temperature sensor connector to the water temperature sensor.
16. Connect the engine harness ignition coil connectors to the three ignition coils.

a - Water temperature sensor

a b - Ignition coil harness connectors (3)

21189

17. Connect the engine harness MAP sensor connector to the MAP sensor.
18. Connect the engine harness trigger connector to the trigger.
19. Connect the engine harness ignition charge connector to the stator.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-35

Charging and Starting System
20. Secure the ignition charge connector, trigger connector, and the alternator connector to the engine wire harness with three
cable ties.

b c

e d
a 21187

a- Cable ties (3)

b- Ignition charge connector
c- Trigger connector
d- MAP sensor connector
e- Alternator connector

21. Connect the engine harness connector to the ECU.

22. Connect the engine harness fuel injector connectors to the three fuel injectors.

a - Fuel injector harness connectors (3)

b - ECU harness connector

b
a

21186

23. Install the electrical cover and secure with two bolts, washers, and spacers. Tighten the bolts to the specified torque.

a - Grommets in the intake manifold

b - Bolts and spacers securing the electrical
cover (2)

a
b

10493

Description Nm lb. in. lb. ft.

Bolts (2) 6 53

24. Install the recoil assembly and timing belt cover. Refer to Section 8A ‑ Manual Starter.

Page 2B-36 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Starter Motor
Starting System Description
The function of the starting system is to crank the engine. The battery supplies electrical energy to crank the starter motor.
When the ignition switch is turned to "START" position, or the starter button on the cowl is pushed in, the starter solenoid is
activated and completes the starting circuit between the battery and starter.
The neutral start switch opens the start circuit when the shift control lever is not in neutral. This prevents accidental starting
when engine is in gear.
The starting system consists of the following components.
• Battery
• Starter solenoid
• Neutral safety switch
• Starter motor
• Ignition key switch/start button

NOTICE
Engaging the starter motor while the engine is operating can damage the starter motor or flywheel. Do not engage the starter
motor continually for longer than 15 seconds. Do not engage the starter motor when the engine is operating.

Troubleshooting the Starting Circuit

Before beginning the starting circuit troubleshooting flowchart, first check for the following conditions:
• Make sure that battery is fully charged.
• Ensure the control lever is in neutral position.
• Check terminals for corrosion and loose connections.
• Check cables and wiring for frayed and worn insulation.
• Check in‑line fuse.

Starter Solenoid Test

1. Disconnect all wires from the solenoid.
2. Connect an ohmmeter between terminals 1 and 2.
3. Connect a 12 volt power supply between the black wire "3", and the green wire "4". The solenoid should click and the
meter should read 0 ohms (full continuity).
4. If the meter does not read 0 ohms (full continuity), replace the solenoid.

1
3

BLK

GRN

2 4 21356

DMT 2004 Digital Multimeter 91‑892647A01

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-37

Charging and Starting System

Starting System Troubleshooting Chart

The following starting circuit troubleshooting chart will locate any malfunction. Location of test points called out in the chart are
numbered in the diagrams.
NOTE: Disconnect the black starter motor cable from starter solenoid at test point 1 before making tests 1 through 7 to prevent
unexpected engine cranking.

c
6 1

BLK
d

b
e

BLK
BLK
7
2
a GRN GRN
GRN

f
4
RED

RED
3
GRN
RED RED

5 23924

Tiller Handle Models

a - Battery
b - Fuse ‑ 20 ampere
c - Starter relay
d - Starter
e - Neutral start switch
f - Ignition key switch

e Remote Control Models

c a - Battery
6 1 b - Fuse ‑ 20 ampere
c - Starter relay
BLK d - Starter
d e - Neutral start switch
YEL/RED

YEL/RED

f - Ignition key switch

b
BLK

BLK 7
GRN

2
a GRN
RED

YEL/RED

f
5 4
RED 3
RED RED

23300

DMT 2004 Digital Multimeter 91‑892647A01

Page 2B-38 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System

Starter Does Not Work

Test
Procedure Test Result
Number
Continuity Indicated: Proceed to Test 2
No continuity indicated: There is an open
circuit in the black negative (‑) battery cable
Use an ohmmeter (R x 1 scale) and connect meter leads between between the negative (‑) battery post and the
Test 1 powerhead.
negative (‑) battery post and common powerhead ground.
• Check cable for loose or corroded
connections
• Check cable for open
1. Change the meter to read voltage. Reading battery voltage: Check the black
2. Disconnect the black ground wire from test point 2. ground wire for poor connection or open
circuit. Reconnect ground wire. Proceed to
Test 2 3. Connect a voltmeter between common engine ground and black
Test 7.
ground wire.
4. Turn the ignition key to "START" or push in the "START" button. No voltage reading: Proceed to Test 3.
1. Reconnect the black ground wire at test point 2. Reading battery voltage: Defective starter
2. Connect voltmeter between common engine ground and test solenoid.
Test 3
point 3.
No voltage reading: Proceed to Test 4.
3. Turn the ignition key to "START" or push in the "START" button.
1. Connect a voltmeter between common engine ground and test Reading battery voltage: The neutral start
point 4. switch is open, or a wire is open between
Test 4 test points 4 and 3.
2. Set the shift control to neutral.
3. Turn the ignition key to "START" or push in the "START" button. No voltage reading: Proceed to Test 5.
1. Connect a voltmeter between common engine ground and test Reading battery voltage: Defective ignition
Test 5 point 5. switch or start button.
2. Turn the ignition key to "START" or push in the "START" button. No voltage reading: Proceed to Test 6.
Reading battery voltage:
• Check the fuse in the red wire between
test points 5 and 6.
1. Connect a voltmeter between common engine ground and test
Test 6 point 6. • Check for a open red wire between test
points 5 and 6.
2. Turn the ignition key to "START" or push in the "START" button.
No voltage reading: Check the black wire
between battery (+) positive terminal and test
point 6.
Reading battery voltage: Listen for the
1. Connect a voltmeter between common engine ground and test
solenoid click. Proceed to Test 8.
Test 7 point 1.
No voltage reading: Defective starter
2. Turn the ignition key to "START" or push in the "START" button.
solenoid.
Reading battery voltage: Check the starter
1. Reconnect the black starter motor cable to the starter solenoid. for a corroded ground to the block. If OK,
check the starter motor.
2. Connect a voltmeter between common engine ground and test
Test 8 No voltage reading: Check the starter black
point 7.
cable for poor connection or open circuit.
3. Turn the ignition key to "START" or push in the "START" button. Check for a bad ground or a defective starter
relay.

Starter Motor Removal

Starter Removal
1. Remove the wire harness. Refer to Engine Wire Harness for the removal of the engine wire harness.
2. Remove the support bracket and the IAC filter.
3. Remove the engine oil filter.
4. Remove the high pressure fuel hose clamp at the VST and remove the fuel hose.
5. Remove the air vent assembly hose from the VST.

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Charging and Starting System

6. Remove the two bolts and washers securing the VST to the cylinder block.
7. Lift the VST off the lower VST mounting grommet.

a- High pressure fuel hose clamp

b- Bolts and washer securing VST
a c c- Air vent assembly hose
d- Oil filter

d
b

10495

8. Remove the two bolts securing the starter brace to the cylinder block.
9. Remove the two bolts securing the starter to the cylinder block. Remove the starter.

a a - Bolts securing the starter to the cylinder block (2)

b - Bolts securing the starter brace to the cylinder block (2)

b 10497

Starter Motor Disassembly

1. Push the pinion stopper down and remove the circlip.
2. Remove the pinion stopper, bendix spring, and bendix.

a a - Circlip
b - Pinion stopper
b c - Bendix

10500

Page 2B-40 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
3. Remove two bolts on the bottom of the starter holding it together.

10502

4. Remove the top end cap. Do not lose any armature shims.
5. Remove the field frame.
6. Remove the armature from the bottom end cap. Do not lose the thrust washer on end of armature.

b c d e a- Armature
b- Top end cap
a c- Field frame
d- Starter motor support insulator
e- Bottom end cap

10504

7. Remove the nut securing the power stud to the end cap insulator.
8. Remove the two screws securing the brush card to the end cap. Remove the brush card.

c a- Nut securing power stud to insulator

b
a b- End cap insulator
c- Screw securing brush card
d- Brushes

d 10503

Starter Motor Reassembly

1. Install the power stud insulator onto the power stud.
2. Insert the power stud through the end cap.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-41

Charging and Starting System
3. Install the two brush card screws. Do not tighten brush card screws.

b a - Power stud
b - Power stud insulator
a c c - Brush card screw (2)

10505

4. Assemble the power stud O‑ring, insulator, washer, lockwasher, and nut onto the power stud. Tighten the nut to the
specified torque.

a a- End cap
b- Power stud
b c- Power stud O‑ring
c d e d- Insulator
f g e- Washer
f- Lockwasher
g- Power stud nut

10508

Description Nm lb. in. lb. ft.

Power stud nut 10 88.5

5. Insert a starter assembly bolt through the end cap to ensure the brush card alignment.
6. Tighten the brush card screws to the specified torque. Remove the bolt from the end cap.

a a - Starter assembly bolt

b - Brush card screw

b 10511

Description Nm lb. in. lb. ft.

Brush card screw (2) 4 35

7. Install the top thrust washer and shims onto the armature.
IMPORTANT: The thrust washer must be installed first onto the armature. The shims must be between the end cap and
the thrust washer.

Page 2B-42 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
8. Install the bottom thrust washer onto the commutator end of the armature.

a b a - Top end cap shims

c b - Top thrust washer
c - Bottom thrust washer

10513

9. Push the brush in and insert a 2.6 mm (.093 in.) drill bit between the brush spring and the brush card. This will hold the
spring and brush for the insertion of the armature into the end cap.
10. Lubricate the end cap bushing with a drop of SAE Engine Oil 30W.

b a- Brush spring
a
b- Drill bit
c- Brush card
c d- End cap bushing

b
d 10520

Tube Ref No. Description Where Used Part No.

80 SAE Engine Oil 30W Starter end cap bushing Obtain Locally
11. Insert the armature into the end cap. Ensure the armature is seated in end cap.
12. Remove the two drill bits to engage the brushes to the commutator.
13. Install the field frame to the end cap. Ensure the locating key of the field frame and the end cap are aligned.

10537

14. Lubricate the armature shaft with SAE Engine Oil 30W and install the top end cap. Ensure the locating keys are in
alignment.

10539

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-43

Charging and Starting System

Tube Ref No. Description Where Used Part No.

80 SAE Engine Oil 30W Armature shaft Obtain Locally
15. Ensure the lockwasher and washer are installed onto the starter assembly bolts.
16. Install two starter assembly bolts. Tighten the bolts to the specified torque.

10502

Description Nm lb. in. lb. ft.

Starter assembly bolt 6 53

17. Lubricate the armature shaft and helix with SAE Engine Oil 30W.

10541

Tube Ref No. Description Where Used Part No.

80 SAE Engine Oil 30W Starter armature shaft, and helix Obtain Locally
18. Install the starter bendix, bendix spring, and pinion stopper. Secure the starter bendix assembly with a circlip. Push the
pinion stopper up to capture the circlip.

a a- Bendix
b b- Bendix spring
c
c- Pinion stopper
d
d- Circlip

22261

Starter Motor Installation

1. Install the starter to the cylinder block. Secure the starter with two bolts and washers. Ensure the rubber mount is properly
centered where it contacts the cylinder block. Tighten the bolts to the specified torque.
2. Install one of the starter brace bolts into the cylinder block. Do not tighten the bolt.

Page 2B-44 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Charging and Starting System
3. Install the remaining starter brace bolt into the cylinder block. Tighten both of the starter brace bolts to the specified torque.

a a - Bolts securing the starter to the cylinder block (2)

b - Bolts securing the starter brace to the cylinder block (2)
c - Rubber mount
c

b 20907

Description Nm lb. in. lb. ft.

Bolts securing the starter to the cylinder block (2) 13 115
Bolts securing the starter brace to the cylinder block (2) 13 115
4. Install the oil filter.
5. Align the VST lower grommet mount with the grommet on the cylinder block.

20909

6. Push the VST onto the grommet and align the upper VST grommets with the cylinder block.
7. Secure the VST to the cylinder block with two bolts and washers. A clamp must be installed on the forward bolt. Tighten
the bolts to the specified torque.
8. Install the air vent assembly hose to the VST.
9. Install a 16.8 mm hose clamp onto the high pressure fuel hose. Install the high pressure fuel hose onto the VST. Secure
the hose clamp with the hose clamp tool.

a- High pressure fuel hose clamp (16.8 mm)

b- Bolts and washer securing VST
a c c- Air vent assembly hose
d- Oil filter

d
b

10495

Hose Clamp Tool Kit 91‑803146A2

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2B-45

Charging and Starting System

Description Nm lb. in. lb. ft.

Bolts and washer securing VST (2) 6 53
10. Install the support bracket and the IAC filter.
11. Install the wire harness. Refer to Engine Wire Harness for the installation of the engine wire harness.
12. Check the engine oil level. Add engine oil as required.
13. Start the engine and inspect for fuel leaks.

Page 2B-46 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Timing, Synchronizing and Adjustments

Electrical
Section 2C - Timing, Synchronizing and Adjustments
Table of Contents 2
C
Ignition Specifications........................................................ 2C-2 Timing Belt Removal.................................................. 2C-3
Idle Timing Adjustment (All Models).................................. 2C-2 Timing Belt Installation .............................................. 2C-4
Maximum Timing Adjustment (All Models)........................ 2C-2 Throttle Linkage Adjustment (Tiller Handle)...................... 2C-6
Timing Belt Removal and Installation ............................... 2C-3 Throttle Linkage Adjustment (Remote Control)................. 2C-8

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2C-1

Timing, Synchronizing and Adjustments

Ignition Specifications
Ignition Specifications at 20 °C (68 °F)
Ignition type Computer controlled CDI (capacitor discharge ignition)
Spark plug NGK DCPR6E
Spark plug gap 0.8–0.9 mm (0.031–0.035 in.)
Firing order 1, 3, 2
Ignition timing at idle 5° ± 5° BTDC
Ignition timing at WOT 38° BTDC
RPM overspeed 6300 RPM
ECM RPM limiter (Guardian) 2800 RPM
Over temperature 90 °C (194 °F)
Low oil pressure (over 5 seconds) 24.5 kPa (3.5 psi)
Crankshaft position sensor 148–222 ohms
Ignition coil
Primary 0.17–0.23 ohms
Secondary 3.3–4.9 k ohms
Spark plug lead (between spark plug cap and black lead) 7.1–11.1 k ohms

Special Tools
CDS G3 Diagnostic Tool Kit 8M0114141

Interfaces CDS G3 software to SmartCraft network.

NOTE: This kit includes download instructions and a license key.

60575

Crankshaft Holding Tool 91‑898101360

Holds the crankshaft while tightening the timing belt drive gear retaining nut.

3455

Idle Timing Adjustment (All Models)

Idle timing is not adjustable. Idle timing is controlled by the PCM/ECM. Idle timing can be monitored with the Computer
Diagnostic System (CDS).

CDS G3 Diagnostic Tool Kit 8M0114141

Maximum Timing Adjustment (All Models)

Maximum timing is not adjustable. Maximum timing is controlled by the PCM/ECM. Maximum timing can be monitored with the
Computer Diagnostic System (CDS).

CDS G3 Diagnostic Tool Kit 8M0114141

Page 2C-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Timing, Synchronizing and Adjustments

Timing Belt Removal and Installation

Timing Belt Removal
IMPORTANT: This engine utilizes an interference valve train design. Do not rotate the crankshaft or cams when the timing belt
is removed from the cam gears or crankshaft gear unless advised to do so. Failure to adhere to this caution may result in valve
and or piston damage.
IMPORTANT: If the timing belt slipped or broke apart while the engine was running, the engine must be disassembled and
inspected for damage.
1. Remove the timing belt cover and recoil assembly. Refer to Section 8 ‑ Manual Starter.
2. Remove the stator assembly. Refer to Section 2A ‑ Stator Removal and Installation.
3. Remove the three bolts securing the stator/crank position sensor (CPS) mounting plate to the engine.
NOTE: It is not necessary to remove the crank position sensors from the stator/CPS mounting plate when replacing the
timing belt.
4. Remove the bolts securing the lifting bracket to the cylinder block.

a - Bolts securing stator/CPS mounting plate

b - CPS
a
c - Bolts securing lifting bracket

b c

9931

5. Ensure the crankshaft timing mark (flywheel key way) and the cam gear timing mark are in proper alignment. If the timing
marks are out of alignment, install the flywheel onto the crankshaft or use the crankshaft holding tool and rotate the engine
so the # 1 timing mark on the cam gear is properly aligned with the mark on the cylinder head. Check for proper alignment
of the crankshaft timing mark.

a a - Crankshaft flywheel key

b b - Cylinder block timing
c mark
d c - Cylinder head timing
mark
d - Cam gear timing mark

9932

Crankshaft Holding Tool 91‑898101360

6. Remove the timing belt tensioner bolt.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2C-3

Timing, Synchronizing and Adjustments
7. Remove the timing belt tensioner. Do not lose the timing belt tensioner spring.

a a - Timing belt tensioner bolt

b - Timing belt tensioner spring
b

9934

8. Lift the timing belt off of the cam gear and drive gear.

9935

Timing Belt Installation

IMPORTANT: This engine utilizes an interference valve train design. Do not rotate the crankshaft or cams when the timing belt
is removed from the cam gears or crankshaft gear unless advised to do so. Failure to adhere to this caution may result in valve
and or piston damage.
1. Ensure the cam gear timing mark for cylinder number one and the cylinder head timing mark are in alignment.

a b a - Cylinder head timing mark

b - Cam gear timing mark

9944
2. Ensure the crankshaft drive gear timing mark and the cylinder block timing mark are in proper alignment.

a - Flywheel key
b - Crankshaft drive gear timing mark
a
c - Cylinder block timing mark

c
9945

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 Timing, Synchronizing and Adjustments
3. Install the timing belt onto the crankshaft drive gear.
4. Install the timing belt onto the cam gear. Ensure the timing belt loose side is towards the starboard side (timing belt
tensioner side).

b a - Timing belt tight side (port side of engine)

b - Timing belt loose side (starboard side of engine)

9946

5. Install the tensioner and tensioner spring.

6. Rotate the crankshaft clockwise one belt tooth and tighten the tensioner bolt to the specified torque.
IMPORTANT: To ensure proper belt tension, the crankshaft must be rotated one belt tooth prior to tightening the belt
tensioner bolt. Failure to load the timing belt in a normal engine rotation will result in a improper belt tension.

a a - Timing belt tensioner bolt

b - Timing belt tensioner spring
b

9934

Description Nm lb. in. lb. ft.

Timing belt tensioner bolt 27 20
7. Install the stator/CPS mounting plate to the engine.
8. Secure the stator/CPS mounting plate to the engine with three bolts. Tighten the bolts to the specified torque.
9. Install the lifting bracket to the engine block.
10. Secure the lifting bracket to the engine block with two bolts. Tighten the bolts to the specified torque.

a - Bolts securing stator/CPS mounting plate

b - CPS
a
c - Bolts securing lifting bracket

b c

9931

Description Nm lb. in. lb. ft.

Bolts securing stator/CPS mounting plate (3) 6 53
Bolts securing lifting bracket (2) 23 17

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2C-5

Timing, Synchronizing and Adjustments
11. Install the flywheel. Refer to Section 2A ‑ Flywheel Removal and Installation.
12. Install the recoil assembly and the timing belt cover. Refer to Section 8 ‑ Manual Starter.

Throttle Linkage Adjustment (Tiller Handle)

1. Ensure the tiller handle throttle/shift cables are properly adjusted. Refer to Section 7B ‑ Tiller Handle.
2. Ensure the tiller handle is in the neutral position and the match mark on the throttle drum and the outer gear plate are in
alignment.

a - Match mark on the throttle drum aligned with the outer gear
a plate match mark

21246

3. Check the shift detent to ensure the shift detent spring is centered on the shift detent.
4. If adjustment is needed, loosen the shift detent spring bolt and adjust the detent spring accordingly. Tighten the shift detent
spring bolt to the specified torque.
IMPORTANT: The detent spring must be in the center of the shift detent. Failure to ensure the detent spring is in the center
of the shift detent, may create an undesirable shifting load in the tiller handle operation.

a - Shift detent center

b b - Shift detent spring
c - Shift detent spring bolt
c

21249

Description Nm lb. in. lb. ft.

Shift detent spring bolt 6 53
5. Remove the upper throttle rod from the throttle body. Do not remove the upper throttle rod from the throttle arm.

Page 2C-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Timing, Synchronizing and Adjustments
6. Remove the lower throttle rod from the throttle barrel and the throttle arm.

a - Upper throttle rod

b - Lower throttle rod

b
21250

7. Push the throttle arm towards the front of the engine. Ensure the throttle arm is contacting the WOT stop on the cowl.

a - Throttle arm contacting WOT stop

b - WOT stop

21253

8. Push the throttle cam to the WOT stop.

9. Adjust the upper throttle rod so it will snap onto the throttle cam when the throttle cam is at WOT.
10. While holding the throttle arm against the WOT stop on the cowl, push on the throttle cam to the WOT position. The throttle
cam should not have any movement.
11. If the throttle cam can be moved, remove the throttle rod from the throttle cam and extend the throttle rod one complete
turn.
12. Check to ensure the throttle cam does not move when the throttle arm is against the WOT stop.

a a - Throttle cam
b - Upper throttle rod

21274

13. Ensure the lower throttle rod is fully threaded onto the joint. Do not tighten the jam nut.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 2C-7

Timing, Synchronizing and Adjustments
14. Install the lower throttle rod to the throttle drum and the throttle arm.
15. Retain the lower throttle rod to the throttle arm with a plastic washer and cotter pin. Do not bend the cotter pin ends until all
the adjustments for the throttle is complete.
16. Rotate the tiller handle throttle grip to the WOT position.
17. Push on the throttle arm with a finger. The throttle arm should not move. Adjust the lower throttle rod joint to remove
throttle arm movement. When there is no throttle arm movement, secure the lower throttle rod to the throttle arm with the
cotter pin. Bend the cotter pin ends to retain the washer and lower throttle rod joint to the throttle arm.

a - Lower throttle rod joint on

throttle arm
c
b - Upper throttle rod
b c - Throttle cam
d - Throttle opener
e - Throttle arm
f f - Throttle drum
a
e

21343

18. Return the tiller handle throttle grip to the idle position.
19. Ensure the throttle cam is not touching the roller on the throttle body.

a - Throttle cam at idle

b - Roller on the throttle body
a

21347

Throttle Linkage Adjustment (Remote Control)

1. Push the throttle arm to the WOT position. The throttle arm must contact the throttle arm stop to ensure the throttle linkage
is adjusted correctly.

Page 2C-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Timing, Synchronizing and Adjustments
2. If the throttle arm does not contact the throttle arm stop, remove the ball socket from the throttle cam and thread the ball
socket into the throttle link several turns to shorten the length of the throttle link.

a - Throttle arm at the WOT

position
a b - Ball socket
c - Throttle arm not contacting the
throttle arm stop

c 22609

3. While holding the throttle arm at the WOT position, push on the throttle cam. The throttle cam should not move when
carefully pushed towards the WOT position.
4. If the throttle cam can be moved, remove the ball socket from the throttle cam and thread the ball socket out one turn.
5. Install the ball socket to the throttle cam and recheck the throttle cam for movement. Repeat the procedure until no
movement of the cam can be seen. Check to ensure the throttle arm is contacting the throttle arm stop.

b a - Throttle arm at the WOT position

b - No movement on throttle cam when
pushed
a
c - Throttle arm contacting the throttle
arm stop

c 22610

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Timing, Synchronizing and Adjustments

Notes:

Page 2C-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Fuel System Operation

Fuel System
Section 3A - Fuel System Operation
Table of Contents

3
Theory of Operation........................................................... 3A-2 Engine Coolant Temperature (ECT) Sensor ..............3A-4
Air Induction System...................................................3A-2 Manifold Absolute Pressure (MAP) Sensor................ 3A-4
Fuel System................................................................3A-2 Manifold Air Temperature (MAT) Sensor....................3A-5
Fuel Pump.................................................................. 3A-2
Vapor Separator......................................................... 3A-2
Throttle Position Sensor (TPS)................................... 3A-5
Oil Pressure Switch.................................................... 3A-5
A
Fuel Pressure Regulator.............................................3A-3 Actuators............................................................................3A-5
Fuel Cooler................................................................. 3A-3 Function of Actuators..................................................3A-5
Throttle Body.............................................................. 3A-3 Engine Control Module............................................... 3A-5
Sensors..............................................................................3A-3 Idle Air Control (IAC)...................................................3A-6
Function of Sensors....................................................3A-3 Fuel Injector................................................................ 3A-7
Crank Position Sensor (CPS)..................................... 3A-4

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3A-1

Fuel System Operation

Special Tools
CDS G3 Diagnostic Tool Kit 8M0114141

Interfaces CDS G3 software to SmartCraft network.

NOTE: This kit includes download instructions and a license key.

60575

Theory of Operation
Air Induction System
The air induction system consists of an intake manifold with an intake runner to each cylinder for a smooth air flow to the
combustion chamber. Each runner has a single fuel injector controlled by the ECM. The fuel injector has several very small
holes in the fuel injector nozzle tip, to help atomize the fuel when injected into the runner as the cylinder valve opens.
A single throttle body/shutter with an attached Throttle Position Sensor (TPS), along with the Idle Air Control (IAC), manages
the amount of air entering the induction system. A Manifold Absolute Pressure (MAP) sensor, and a Manifold Air Temperature
(MAT) sensor, send manifold pressure and temperature information to the ECM to regulate the fuel injector pulse width, and
modulates the IAC duty cycle.

Fuel System
The fuel system consists of a fuel line connector, a fuel filter, a low‑pressure mechanical fuel pump, a high‑pressure electric
fuel pump, a vapor separator tank, a high pressure fuel filter, fuel injectors, a fuel cooler, and a fuel pressure regulator. The
low‑pressure mechanical fuel pump draws fuel from the fuel tank, through the fuel line connector, and fuel filter. The fuel pump
then delivers it to the high‑pressure fuel pump inside the vapor separator tank. High‑pressure fuel is circulated through a fuel
cooler, and a high‑pressure fuel filter prior to supplying fuel to the fuel rail. The fuel injectors spray fuel into the intake manifold
as the valve opens. Fuel not injected into the fuel rail, flows through pressure regulator, and returns to the vapor separator tank.

Fuel Pump
The fuel pump is a mechanically driven diaphragm pump which is driven off of the camshaft. The pump base insulates the fuel
pump from the heat of the cylinder head/valve cover. If the engine runs out of fuel, or has a restriction on the vacuum side of
the pump preventing adequate fuel flow, the pump will make an audible clicking noise.

21124

Vapor Separator
The vapor separator maintains a liquid fuel supply for the high‑pressure fuel pump that is located inside the vapor separator
tank. Fuel delivered from the mechanical low‑pressure fuel pump is supplied to the top of the vapor separator, and is controlled
by the inlet needle/float assembly. Pressurized fuel from the high‑pressure fuel pump, circulates through the fuel cooler, passes
through the high‑pressure fuel filter, and into the fuel rail where the fuel injectors control the duration volume of fuel entering the
combustion chamber. Excess fuel flows through the pressure regulator back to the vapor separator tank.

21110

Page 3A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Fuel System Operation

Fuel Pressure Regulator

The fuel pressure regulator is mounted on top of the vapor separator. It maintains a stable fuel pressure between the
high‑pressure fuel pump and the fuel injectors. The pressure regulator consists of a spring‑loaded diaphragm which actuates a
valve/seat assembly. Excess fuel pressure unseats the valve inside the fuel pressure regulator, returning fuel to the vapor
separator tank. The excess fuel is channeled below the fuel level in the vapor separator tank through an internal pipe to prevent
fuel vaporization. The spring side of the diaphragm is vented to the ambient atmosphere, allowing barometric conditions to act
on the diaphragm in addition to spring pressure.

a a - Vent to ambient atmosphere

b - High‑pressure fuel from fuel cooler
c - Excess fuel to VST tank

9451
c

Fuel Cooler
The fuel cooler works as a fuel heat exchanger. It circulates engine cooling water through a manifold to cool the high‑pressure
fuel supply to the fuel injectors. Lowering the fuel temperature by removing heat from the circulating high‑pressure fuel,
prevents the formation of fuel vapors, and reduces the probability of fuel vapor lock.

21109

Throttle Body
The throttle body is connected to the intake manifold. It controls the amount of air that is allowed into the intake manifold. The
throttle body affects the Manifold Absolute Pressure (MAP). When the throttle body valve is closed (idle), the air pressure inside
the intake manifold is in a vacuum state. When the throttle body valve opens, the vacuum condition of the intake manifold drops
proportionally to the position of the throttle body valve. At WOT, the condition of the air inside the intake manifold continues to
be in a vacuum state, but is significantly less of a vacuum than when at an idle position. These changes of the vacuum inside
the intake manifold, affects the MAP sensor, allowing the ECM to change the fuel injection strategy, and the ignition timing.

21112

Sensors
Function of Sensors
The sensors are some of the key components for controlling optimum fuel efficiency, horsepower, and emissions for internal
combustion engines. Each sensor is designed to monitor for a specific condition or identify a location. These condition and
location sensors supply vital information to the ECM. The sensors, in conjunction with the ECM, manage the fuel system, the
ignition system, and the warning system, based on the information received from these condition and location sensors.

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Fuel System Operation

Crank Position Sensor (CPS)

The Crank Position Sensor (CPS) is a hall effect switch. A hall effect switch senses the collapse of a magnetic field. The outer
ring of the flywheel has a raised key or tooth on it. As the flywheel rotates, the CPS senses the location of the crankshaft via the
collapse of the magnetic field caused by the tooth passing the CPS. The CPS supplies the trigger signal information to the
ECM. The ECM utilizes the CPS information and determines when to trigger each ignition coil and fuel injector. The CPS
provides the ECM with engine RPM information, which the ECM uses in determining fuel delivery, spark timing, and over
revolution protection.

21117

Engine Coolant Temperature (ECT) Sensor

The Engine Coolant Temperature (ECT) sensor is located at the top of the cylinder block, aft of the flywheel. It is a thermistor
immersed in the engine coolant path, after the thermostat. It supplies the ECM with engine temperature information. The ECM
adjusts the timing, and the volume of fuel delivered via the fuel injectors, according to the water temperature in the cylinder
block. Low coolant temperature produces high resistance, while high coolant temperature causes low resistance.
When an engine coolant temperature condition occurs over 90 °C (194 °F), the warning horn will sound continuously and the
warning light will be illuminated continuously. When the engine coolant temperature is below 90 °C (194 °F), the warning horn
and the warning lamp turn off.
Should the sensor fail or become disconnected, the warning horn will sound intermittently, the warning lamp will be intermittent
and the engine RPM will be reduced to 2800 or less. The engine must be stopped to cancel the warning.

21113

Manifold Absolute Pressure (MAP) Sensor

The Manifold Absolute Pressure (MAP) sensor measures relative changes in the intake manifold, whether in a vacuum
condition or pressure condition. It is mounted on the intake manifold. A hose connected to the intake manifold, after the throttle
body/shutter, is connected to the MAP sensor. When the engine is rotating during start‑up, the rotating flywheel generates
voltage through the stator to energize the ECM. The ECM then reads the ambient atmospheric pressure through the MAP
sensor. This information is used by the ECM as an indication of altitude and/or the density of the air. The manifold absolute
pressure will change as a direct result of engine load and RPM. This information is used by the ECM to calculate optimum fuel
delivery volume, and spark timing.
Should the sensor fail or become disconnected, the warning horn will sound intermittently, the warning lamp will be intermittent,
and the engine RPM will be reduced to 2800 or less. The engine must be stopped to cancel the warning.

21105

Page 3A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Fuel System Operation

Manifold Air Temperature (MAT) Sensor

The Manifold Air Temperature (MAT) sensor is a thermistor that controls a signal voltage to the ECM. It is located outside the
intake manifold, near the throttle body/shutter. It informs the ECM of the air temperature inside the engine cowl. The ECM
adjusts the fuel injection volume needed to run the engine at optimum efficiency according to the MAT information. When intake
air is cold, the sensor resistance is high. As the air temperature rises, resistance lowers.

21104

Throttle Position Sensor (TPS)

The Throttle Position Sensor (TPS) is located on the throttle body, and is in direct contact with the throttle shaft. The TPS
transmits throttle angle information to the ECM which regulates the fuel injector volume (pulse width) and ignition timing. Should
the sensor fail, a warning horn will sound and the engine RPM will be reduced by the ECM.

21103

Oil Pressure Switch

The oil pressure switch is located on the port side of the engine, and protrudes into the pressurized oil galley after the oil filter.
The sensor sends a signal to the ECM indicating a low oil pressure condition, which activates a warning horn. Engine RPM will
automatically be reduced when the oil pressure is below the minimum specification.
During a low oil pressure condition for more than 5 seconds, the warning horn will sound continuously, the warning lamp will be
illuminated continuously, and the engine RPM will be reduced to 2800 or less. The engine must be stopped to cancel the
warning.

21122

Actuators
Function of Actuators
Actuators receive output signals from the ECM, and perform functions which control air‑fuel ratios, spark advance, and idle
RPM. The actuators maintain optimal fuel economy as a direct relation to the engine horsepower.

Engine Control Module

The ECM requires 5 volts to operate. If the ECM should fail, the engine will stop running. Inputs to the ECM can be monitored
and tested by the computer diagnostic system (CDS).

CDS G3 Diagnostic Tool Kit 8M0114141

The ECM performs the following functions:

• Calculates precise fuel and ignition timing requirements based on engine speed, throttle position, manifold pressure,
manifold air temperature, and engine coolant temperature.
• Directly controls the ground circuit of fuel injectors, ignition coils, high‑pressure fuel pump, and idle air control.
• Indirectly controls the positive circuit of fuel injectors, ignition coils, and idle air control.
• Controls alarm horn and warning functions.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3A-5

Fuel System Operation
• Controls RPM limit function.
• Records engine running information.

ECM Systems Control Matrix

ECM Control Item Description Parameter
Ignition timing Controls the optimum ignition timing according to the current operating conditions
Controls the fuel injection pulse width (duration) for optimum efficiency according to current operating
Fuel injection
condition
Stabilizes the engine RPM when idling and during quick engine RPM deceleration by managing the
Idle air control (IAC)
duty cycle driving the IAC in order to control bypass air entering the intake manifold
Tachometer Sends out six tachometer pulses per engine revolution (12 pole)
After Starting:
Short beep for two seconds after the engine is initially started indicating all sensors are functioning
Continuous Sound:
Warning horn During engine over RPM, engine coolant temperature is over 90 °C (194 °F), engine oil pressure is
24.5 kPa (3.6 psi).
Intermittent Sound:
MAP sensor or engine coolant temperature sensor is defective or is disconnected
After Starting:
Illuminated for five seconds after the engine is initially started indicating all sensors are functioning
Continuous Illumination:
Warning lamp During engine over RPM, engine coolant temperature is over 90 °C (194 °F), engine oil pressure is
24.5 kPa (3.6 psi).
Intermittent Illumination:
MAP sensor or engine coolant temperature sensor is defective or is disconnected
Engine running time
Memorizes Over temperature and time of occurrence
operation data Engine Guardian (over RPM, and RPM reduction to 2800 or less)
Sensor failures

Idle Air Control (IAC)

The idle air control (IAC) is an electrically operated spring‑loaded solenoid valve which controls the amount of air bypassing the
closed throttle shutter. Signals from the ECM regulate the duty cycle that the IAC valve remains open, or closed. The IAC
controls three operating functions:
• Provides additional intake air for engine during start‑up, and allows increased idle RPM during engine warm‑up.
• Controls idle speed according to the varying engine loads, and running conditions.
• Functions as an electronic dashpot by providing additional bypass air as the throttle quickly closes during a rapid
deceleration, preventing engine stalling.

21101

Page 3A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Fuel System Operation

Fuel Injector
The fuel injector is an electrically operated spring‑loaded solenoid, which delivers a metered amount of fuel into the intake
manifold runner, just ahead of the intake valve. The injectors are electrically charged by the ECM through the stator assembly
when the flywheel starts to rotate. The ECM controls the injection by completing the ground circuit, lifting the solenoid, which
allows high‑pressure fuel to flow through the fuel injector. The ECM then opens the ground circuit, allowing the spring to close
the injector, and stop the fuel flow. An injector filter is located on the fuel inlet side of the injector. The filter is not replaceable,
but can be cleaned of debris.

21100

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3A-7

Fuel System Operation

Notes:

Page 3A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Troubleshooting and Diagnostics

Fuel System
Section 3B - Troubleshooting and Diagnostics
Table of Contents

3
Troubleshooting Without a Computer Diagnostic System Guardian Protection System.............................................. 3B-5
(CDS)............................................................................. 3B-3 Guardian Warning System Control Matrix......................... 3B-5
Troubleshooting with the Computer Diagnostic System Anti‑Siphon Valves.............................................................3B-6
(CDS)............................................................................. 3B-3
Accessing ECM Information with the CDS.........................3B-4
Testing Fuel Lift Pump Vacuum.........................................3B-6
Fuel Pressure Test.............................................................3B-7
B
Fault Information.........................................................3B-5

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3B-1

Troubleshooting and Diagnostics

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
25 Liquid Neoprene Grounds and ring terminals 92- 25711 3

Special Tools
CDS G3 Diagnostic Tool Kit 8M0114141

Interfaces CDS G3 software to SmartCraft network.

NOTE: This kit includes download instructions and a license key.

60575

Adapter Harness 84‑899150T01

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).
22175

Adapter Harness 84‑822560A7

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).

13422

Fuel Pressure Gauge Kit 91‑881833A03

Tests the fuel pump pressure; can be used to relieve fuel pressure.

2807

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1

Tests fuel and air pressure; the dual gauges allow the viewing of both pressures
simultaneously.

5822

Page 3B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Troubleshooting and Diagnostics

Digital Pressure Meter 91‑892651A01

Connects to the fuel system/manifold and can be used in conjunction with

Computer Diagnostic System (CDS).

5786

Troubleshooting Without a Computer Diagnostic System (CDS)

Troubleshooting without the CDS (Computer Diagnostic System) is limited to checking resistance on some of the sensors.
Typical failures usually do not involve the ECM. Most likely at fault are the connectors, set‑up, and mechanical wear.
• The engine may not run or may not run above idle with the wrong spark plugs installed.
• Swap ignition coils to see if the problem follows the coil or stays with the particular cylinder.
• Any sensor or connection can be disconnected and reconnected while the engine is operating without damaging the ECM.
Disconnecting the crank position sensor will stop the engine.
IMPORTANT: Any sensor that is disconnected while the engine is running will be recorded as a fault in the ECM Fault
Hours.
• If all cylinders exhibit similar symptoms, the problem is with a sensor or harness input to the ECM.
• If problem is speed related or intermittent, it is probably connector or contact related. Inspect connectors for corrosion,
loose wires or loose pins. Secure connector seating. If dielectric compound was used to protect the wire connections, the
dielectric compound must be removed.
• Inspect the harness for obvious damage: pinched wires, chaffing.
• Check fuel pump connections and fuel pump pressure.
• Secure grounds and all connections involving ring terminals. Coat grounds and ring terminals with Liquid Neoprene.

Tube Ref No. Description Where Used Part No.

25 Liquid Neoprene Grounds and ring terminals 92- 25711 3

Troubleshooting with the Computer Diagnostic System (CDS)

The ECM is designed that if a sensor fails, the ECM will compensate so that the engine does not go into an over‑rich condition.
Because of this, disconnecting a sensor for troubleshooting purposes may have no noticeable effect.
The CDS has been developed specifically to help technicians diagnose and repair Mercury Marine 2 and 4 cycle engines.

CDS G3 Diagnostic Tool Kit 8M0114141

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3B-3

Troubleshooting and Diagnostics
Attach the 84‑899150T01 diagnostic cable to the ECM diagnostic port and attach the 84‑822560A7 adapter to the
84‑899150T01 diagnostic cable. The CDS will monitor sensors and ECM data values including status switches. The ECM
program can help diagnose intermittent engine problems. It can record the state of the engine sensors and switches for a
period of up to 10 minutes, which then can be played back and analyzed.

a a - Diagnostic port
b b - ECM

23249

Adapter Harness 84‑899150T01

Adapter Harness 84‑822560A7

When using the CDS for troubleshooting, follow the CDS driven troubleshooting menu for the complete diagnostic
troubleshooting procedures.

Accessing ECM Information with the CDS

The CDS allows the technician to specifically identify the engine to be tested. It is important to accurately identify the engine
because in many cases, the available testing options depend on the engine identified. It is also capable of storing customer
contact information and will identify the required diagnostic cables for the engine selected.

CDS G3 Diagnostic Tool Kit 8M0114141

The Pinpoint Diagnostics (when applicable) allows the technician to identify the cause of a fault code down to the component
level. Pinpoint Diagnostic test results can be stored in the CDS.
Fault codes can be displayed active or historic. The Fault Status displays the code number, description, and the source of the
faults. Fault Hours displays a fault number and text that corresponds to the exact moment in the engines' run history the fault
was set.
When the 84‑899150T01 diagnostic cable is plugged into the ECM diagnostic port, a special service mode is activated within
the ECM. When the special service mode is activated, the ECM will not log run time, nor will it allow any fault hours to be set.
Any previously logged run time and fault hours can be reviewed for diagnostic purposes, but the run time will not increase and
no new fault hours can be set when the ECM is in the service mode. During a water test, the data stream and any faults that
occur during the water test, will be recorded. The water test does not affect the logging of faults, run history, or system
information.
The diagnostic cable connection supplies power to the ECM. Disconnecting sensors and actuators while the ECM is powered
up in the special service mode, will cause faults to be displayed in the faults status screen. These faults will not be recorded in
the memory fault hours. The CDS will not clear (erase) faults hours at the time of this service manual printing.
The System Information screen will display an alpha‑numeric code identifying a specific calibration in the ECM.

Page 3B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Troubleshooting and Diagnostics

Fault Information
Fault Information
CDS Screen Display Description
ACG Coil 1, 2, 3 ACG Coil faults #1 through #3
IGN 1, 2, 3 Ignition coil fault code #4 through #6.
INJ 1, 2, 3 Fuel injector fault code #7 through #9.
Fuel Pump Circuit High pressure fuel pump fault code #10
(Idle Speed Control) Fault code #11. May be referred to as IAC (Idle
ISC
Air Control).
Fault Status ‑ Active Faults
Throttle Position Sensor Throttle position sensor fault code #12.
Intake Temperature Sensor Intake temperature sensor fault code #13.
Water Temperature Sensor Water temperature sensor fault code #14.
Pressure sensor fault code #15. May be referred to as MAP
Pressure Sensor
(Manifold Absolute Pressure).
Oil Pressure Sensor Oil pressure sensor fault code #16.

Data Stream Information

CDS Screen Display Description
ACG Stator voltage driving the engine operating systems
Engine Speed Engine RPM
The amount of voltage the ECM is receiving through the engine stator or
Driver Power
diagnostic cable.
Baro Pressure Ambient air pressure.
Manifold Pressure May be referred to as MAP (Manifold Absolute Pressure).
Throttle Position Percentage of throttle angle.
Ignition Timing Ignition timing displayed in degrees BTDC.
Data List IAC Duty Cycle ISC (Idle Speed Control) activation percentage 0 ‑ 100%.
Engine Coolant Temperature Cylinder block water temperature.
Fuel Flow Rate Amount of calculated fuel consumption.
INJ Pulse Width Fuel injector activation duration ms (milliseconds).
Low oil pressure displayed in the CDS as:
Low Oil Pressure Switch • Engine running ON (adequate oil pressure)
• Engine not running OFF (low oil pressure)
Ignition key is OFF, lanyard stop switch active: displayed in the CDS as ON.
Stop Switch
Ignition key is ON, lanyard stop switch is open: displayed in the CDS as OFF.

Guardian Protection System

The Guardian Protection System monitors critical engine functions and will reduce engine power accordingly in an attempt to
keep the engine running within safe operating parameters.
IMPORTANT: The Guardian Protection System cannot guarantee that powerhead damage will not occur when adverse
operating conditions are encountered. The Guardian Protection System is designed to 1) warn the boat operator that the
engine is operating under adverse conditions and 2) reduce power by limiting maximum RPM in an attempt to avoid or reduce
the possibility of engine damage. The boat operator is ultimately responsible for proper engine operation.

Guardian Warning System Control Matrix

The warning horn will emit either a continuous beep or intermittent short beeps and the engine speed will be limited. This will
alert the operator and help identify the following listed situations.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3B-5

Troubleshooting and Diagnostics

Warning System
Engine Speed
Function Sound Warning Light Description Limited to 2800
RPM
One beep for 2
Start up On for 5 seconds Normal system test
seconds
Engine over temperature Continuous On Engine overheat X
Low oil pressure Continuous1. On Low oil pressure X
Engine speed exceeds maximum
Engine overspeed Continuous On
allowable ‑ 6300 RPM

Intermittent short Engine speed will limited ‑ 2800

Water temp or MAP sensor
Flashes RPM. Consult your dealer for X
out of range beep1. assistance

Anti‑Siphon Valves
While anti‑siphon valves may be helpful from a safety standpoint, they clog with debris, they may be too small, or they may
have too heavy a spring. The pressure drop across these valves can, and often does, create operational problems and/or
powerhead damage by restricting fuel to the fuel lift pump and, subsequently, the high‑pressure fuel pump. Some symptoms of
restricted (lean) fuel flow, which could be caused by use of an anti‑siphon valve, are:
• Severe fuel rail pressure fluctuation
• Loss of fuel pump pressure
• High speed surging
• Outboard cuts out or hesitates upon acceleration
• Outboard runs rough
• Outboard quits and cannot be restarted
• Outboard will not start
• Vapor lock
Since any type of anti‑siphon device must be located between the outboard fuel inlet and fuel tank outlet, a simple method of
checking if such a device (or bad fuel) is a problem source, is to operate the outboard with a separate fuel supply which is
known to be good, such as a remote fuel tank.
If, after using a separate fuel supply, it is found that the anti‑siphon valve is the cause of the problem, there are two solutions to
the problem; either 1) replace the anti‑siphon valve with one that has a lighter spring tension, or 2) replace it with a
solenoid‑operated fuel shut off valve.

Testing Fuel Lift Pump Vacuum

1. Separate the engine fuel line and the boat fuel line.
2. Install a t‑fitting on the boat fuel line.
3. Install a clear fuel line on the opposite side of the t‑fitting.
4. Connect the clear fuel line to the engine fuel line.
5. Install a fuel vacuum gauge (obtain locally) on the t‑fitting.
6. Clamp all fuel line connections securely to prevent vacuum leaks.
7. Start engine.
8. Observe clear fuel line for air bubbles.

1. Stop engine to cancel warning notification.

Page 3B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Troubleshooting and Diagnostics
9. The vacuum gauge reading should be within the listed specification when the pump is active.

a- Engine fuel line

b- Clear fuel line
c- T‑fitting
d- Boat fuel line

a d
b c

4439

Fuel Lift Pump Vacuum

at idle 8.4 kPa (2.5 in. Hg)

Fuel Pressure Test

1. Install a fuel pressure gauge onto the fuel pressure Schrader valve located on the fuel rail.
2. Start the engine. The fuel pressure should be within specification.
NOTE: The ambient barometric air pressure will have a direct affect on the fuel pressure reading.

9999

Fuel Pressure Specification

at 850 RPM 294 kPa (42.6 psi)

Fuel Pressure Gauge Kit 91‑881833A03

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1
Digital Pressure Meter 91‑892651A01

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3B-7

Troubleshooting and Diagnostics

Notes:

Page 3B-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Fuel System
Section 3C - Service Procedures
Table of Contents

3
Fuel System Specifications................................................3C-2 Fuel Cooler Disassembly and Reassembly..............3C-33
Fuel Pump Components.................................................... 3C-4 Fuel Cooler Installation.............................................3C-34
Fuel Rail and Vapor Separator Components.....................3C-6 Throttle Body .................................................................. 3C-35
Fuel Cooler and Vapor Separator Components................ 3C-8
Intake Manifold Components........................................... 3C-10
Throttle Body Removal............................................. 3C-35
Throttle Body Disassembly and Reassembly........... 3C-36
C
Fuel Lift Pump..................................................................3C-12 Throttle Body Installation.......................................... 3C-38
Fuel Lift Pump Removal .......................................... 3C-12 Fuel Rail...........................................................................3C-40
Fuel Lift Pump Disassembly and Reassembly......... 3C-13 Fuel Rail Removal.................................................... 3C-40
Fuel Lift Pump Installation........................................ 3C-16 Fuel Rail Disassembly.............................................. 3C-42
High Pressure Fuel Filter................................................. 3C-18 Fuel Rail Reassembly...............................................3C-42
High Pressure Fuel Filter Removal...........................3C-18 Fuel Rail Installation................................................. 3C-44
High Pressure Fuel Filter Installation .......................3C-19 Intake Manifold................................................................ 3C-45
Vapor Separator Tank (VST)........................................... 3C-20 Intake Manifold Removal ......................................... 3C-45
VST Removal........................................................... 3C-20 Intake Manifold Installation....................................... 3C-46
VST Disassembly..................................................... 3C-22 Idle Air Control (IAC)........................................................3C-48
VST Reassembly......................................................3C-24 IAC Removal............................................................ 3C-48
VST Installation........................................................ 3C-29 IAC Installation......................................................... 3C-50
Fuel Cooler...................................................................... 3C-31 Wire Color Code Abbreviations................................ 3C-52
Fuel Cooler Removal................................................3C-31 IAC Test....................................................................3C-53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-1

Service Procedures

Fuel System Specifications

Fuel System Specification
Fuel system Computer controlled sequential multiport electronic fuel injection
Fuel type Automotive unleaded (regular)
Mechanical plunger, diaphragm
Fuel pump type
Electric
Fuel pump pressure (mechanical) 29 kPa (4.2 psi)
Fuel pump pressure (electric) 294 kPa ± 10% (42.6 psi ± 10%)

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
66 Loctite 242 Threadlocker Bolt threads retaining the throttle cam to the throttle body 92-809821
Fuel inlet tube O-rings
10W-30 4-Stroke Marine
110 Fuel rail Schrader valve 92-8M0078625
Engine Oil
Fuel injector O-rings

Special Tools
Fuel Pressure Gauge Kit 91‑881833A03

Tests the fuel pump pressure; can be used to relieve fuel pressure.

2807

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1

Tests fuel and air pressure; the dual gauges allow the viewing of both pressures
simultaneously.

5822

Digital Pressure Meter 91‑892651A01

Connects to the fuel system/manifold and can be used in conjunction with

Computer Diagnostic System (CDS).

5786

Page 3C-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Hose Clamp Tool Kit 91‑803146A04

Aids in the installation of high pressure hose clamps. Clamp Tool (91‑803146T)

5819

Hose Clamp Tool Kit 91‑803146A2

Aids in the installation of high pressure (Oetiker ®) hose clamps.

5819

CDS G3 Diagnostic Tool Kit 8M0114141

Interfaces CDS G3 software to SmartCraft network.

NOTE: This kit includes download instructions and a license key.

60575

Adapter Harness 84‑899150T01

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).
22175

Adapter Harness 84‑822560A7

Data link harness between the engine ECM and the Computer Diagnostic
System (CDS).

13422

Extension Cable 84‑825003A 1

Data link extension harness (3.05 m [10 ft.]) between the adapter harness and
the Digital Diagnostic Terminal or Computer Diagnostic System (CDS).

4012

DMT 2004 Digital Multimeter 91‑892647A01

Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC

V Hz
H z TEMP
mA
A
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
mV IG
OFF IP

TEMP

A mA COM V Hz

4516

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-3

Service Procedures

Fuel Pump Components

3

4 1
2

4
5
9
10
6 7
11

12
9 16
15
32
13

19

4 33
20 17
31 14
4

4
21 18

22
23
9
30

26 26 24
26
29
28 21

27 25

18679

Page 3C-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Fuel Pump Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Fuel pump
2 2 Bolt 6 53
3 1 Hose
4 AR Clip
5 1 O‑ring
6 1 Bracket
7 1 Rubber mount
8 1 Plate
9 3 Bolt (M6 x 16) 6 53
10 1 Nut
11 1 Washer
12 1 Fuel cooler gasket
13 1 Fuel filter
14 1 Hose
15 1 Fuel cooler
16 2 Bolt 6 53
17 1 Hose
18 1 Connector
19 1 Clamp (16.8)
20 1 Hose
21 2 Clip
22 1 Rubber mount
23 1 Bracket
24 1 High pressure fuel filter
25 1 Hose
26 3 Clamp
27 1 Fitting
28 1 Hose
29 1 Sleeve
30 1 Hose
31 1 Hose
32 1 Collar
33 4 Cable tie

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-5

Service Procedures

Fuel Rail and Vapor Separator Components

8 5
7
4
3
6
21 2

12 10
15
11 9
13

16
14

20

18 17
23

27
24
26
36 24
19
25 28
22
27
27

3235

29
34
3332
31
30
24

18685

Page 3C-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Fuel Rail and Vapor Separator Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Fuel rail
2 1 O‑ring
3 1 Connector
4 1 Valve assembly
5 1 Cap
6 1 Plate
7 1 Screw 4 35
8 3 Bolt 6 53
9 3 Fuel injector
10 3 O‑ring
11 3 O‑ring
12 1 Spring clamp
13 1 Screw 4 35
14 1 Nipple
15 2 O‑ring
16 1 Clip
17 1 Clip
18 1 Hose
19 1 Vent fitting
20 1 Cable tie
21 1 Clamp
22 1 Orifice
23 1 Air vent assembly
24 3 Clip
25 1 Hose
26 1 Hose
27 3 Clamp (16.8)
28 1 Hose
29 1 Vapor separator
30 3 Bolt 6 53
31 1 Clamp
32 6 Washer
33 3 Grommet
34 3 Spacer
35 3 Grommet
36 1 Sleeve

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-7

Service Procedures

Fuel Cooler and Vapor Separator Components

4
5
22
6 7

23
1 8 9
12
14

13

15
23 21 10
24 24 16
23 11

17

22

20 19
18

18695

Page 3C-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Fuel Cooler and Vapor Separator Components

Ref. Torque
No. Qty. Description Nm lb. in. lb. ft.
1 1 Vapor separator
2 2 Screw 6 53
3 1 Fuel pressure regulator
4 1 Grommet
5 1 O‑ring
6 1 Drain screw O‑ring
7 5 Screw 6 53
8 1 Insulator
9 1 Grommet
10 1 Fuel pump
11 1 Filter
12 1 Inlet needle and seat
13 1 Clip
14 1 Pin
15 1 Float
16 1 Screw 4 35
17 1 O‑ring
18 1 Drain screw
19 1 Drain screw O‑ring
20 1 Hose
21 1 Fuel cooler
22 4 Screw 6 53
23 6 O‑ring
24 2 O‑ring

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-9

Service Procedures

Intake Manifold Components

8
2 6 7
3 7

1 9
9

4 30
31 10
13
15

11 14
12
17
18
19 22 29
20 24
16
18 26
21 23
27
25
28

19527

Page 3C-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Intake Manifold Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Intake manifold
2 1 Bolt 6 53
3 1 Washer
4 2 Dowel pin
5 3 Bolt 9 80
6 3 Bolt 9 80
7 6 Washer
8 3 Nut
9 6 O‑ring
10 1 Insulator
11 1 Throttle body assembly
12 1 Gasket
13 2 Bolt 6 53
14 1 Grommet
15 1 Air horn
16 2 Bolt 6 53
17 1 Spring
18 2 Washer
19 1 Bushing
20 1 Cam
21 1 Bolt 6 53
22 1 Bracket
23 2 Bolt 6 53
24 1 Grommet
25 1 Intake silencer
26 1 Cover
27 1 Gasket
28 1 Filter
29 2 Self tapping screw
30 1 Plug
31 1 Band

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-11

Service Procedures

Fuel Lift Pump

Fuel Lift Pump Removal
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

1. Remove the two bolts securing the cowl latch pivot rod and detent spring.

a a - Bolt securing cowl latch pivot rod (2)

b - Cowl latch detent spring
c - Cowl latch lever

c 11610

2. Push the cowl latch pivot rod to the port side to remove from the cowl latch lever. Do not lose the washers located between
the cowl latch pivot rod and the lower cowl.
NOTE: Some models do not have washers between the cowl latch pivot rod and the lower cowl.

a - Washers (4)

a 11611

Page 3C-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
3. Remove the cowl latch lever and the cowl latch seal.

a - Cowl latch lever

b b - Cowl latch seal

11612

4. Remove the two bolts securing the fuel pump to the cylinder head cover.

b a - Lower cowl (aft view)

a b - Fuel pump
c - Fuel pump bolts

c
10024

5. Pull the fuel pump assembly from the cylinder head cover.
6. Remove the fuel in and fuel out hoses from the fuel pump.

a - Fuel in hose
b - Fuel out hose
a b

10031

Fuel Lift Pump Disassembly and Reassembly

Fuel Lift Pump Disassembly
1. Remove the O‑ring seal from the fuel pump.
2. Remove the four T20H Torx screws from the fuel pump.

b a - O‑ring
b - T20H Torx screw

a
10032

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-13

Service Procedures

3. Separate the fuel pump diaphragm housing from the check valve assembly.
NOTE: The check valve assembly is not serviceable. Replace as needed.

a - Check valve assembly

(not serviceable)
a
b - Fuel pump diaphragm
b housing

10033

4. Squeeze the fuel pump plunger and the diaphragm together. Rotate the fuel pump diaphragm housing to access the
diaphragm pin. Remove the diaphragm pin.

a a- Fuel pump plunger

b- Diaphragm pin
b c- Fuel pump diaphragm housing
d- Diaphragm

c
d 10034

5. Inspect the fuel pump diaphragm and the fuel pump diaphragm spring for damage. Replace as needed.

Fuel Lift Pump Reassembly

1. Assemble the fuel pump components.

a b c d e f a- Plunger
b- Diaphragm pin
c- Plunger spring
d- Fuel pump diaphragm housing
e- Diaphragm spring
f- Diaphragm

10037

2. Install the diaphragm spring onto the diaphragm.

3. Insert the diaphragm with the spring into the fuel pump diaphragm housing. Ensure the diaphragm shaft is in proper
alignment to accept the diaphragm pin.
4. Install the plunger spring and plunger onto the fuel pump diaphragm housing.
5. Compress the diaphragm and plunger.
6. Insert the diaphragm pin into the plunger.

a a- Fuel pump plunger

b- Diaphragm pin
b c- Fuel pump diaphragm housing
d- Diaphragm

c
d 10034

Page 3C-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

7. Align the diaphragm tab with the fuel pump diaphragm housing key.

a - Diaphragm tab
a b - Fuel pump diaphragm housing key

b
10040

8. With the diaphragm tab located in the fuel pump diaphragm housing key, check to ensure the drain hole in the end of the
plunger is opposite the fuel pump diaphragm housing plunger guide opening. If the orientation of the plunger is not correct,
the diaphragm pin must be removed, and the plunger rotated 180° to correct the alignment.

a a - Fuel pump diaphragm housing plunger guide opening

b - Plunger drain hole

b 10041

9. Align the check valve assembly and the fuel pump diaphragm housing. The check valve assembly fuel inlet must be
orientated in the same direction as the plunger drain hole on the fuel pump diaphragm housing.

a - Check valve assembly fuel inlet

b - Plunger drain hole on the fuel pump diaphragm
housing
b

a 10044

10. Install the fuel pump screws. Tighten the fuel pump screws to the specified torque.
11. Install the O‑ring.

b a - O‑ring
b - T20H Torx screw

a
10032

Description Nm lb. in. lb. ft.

Fuel pump screws (T20H Torx) 5.5 50

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-15

Service Procedures

Fuel Lift Pump Installation

1. Install the fuel in and fuel out hoses to the fuel pump assembly. Secure the fuel in and fuel out hoses with spring clamps.

a - Fuel in hose
b - Fuel out hose
a b

10031

2. Install the fuel pump assembly with the hoses attached to the cylinder head cover.
3. Secure the fuel pump assembly to the cylinder head cover with two bolts. Tighten the bolts to the specified torque.

b a - Lower cowl (aft view)

a b - Fuel pump
c - Fuel pump bolts (2)

c
10024

Description Nm lb. in. lb. ft.

Fuel pump bolts (2) 6 53
4. Install the cowl latch seal onto the lower cowl. Ensure the cowl latch seal fulcrum is in proper position on the lower cowl
during the installation.

c a - Cowl latch seal fulcrum

b - Lower cowl
c - Fuel pump

b
11614

Page 3C-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
5. Insert the cowl latch lever through the cowl latch seal.

a - Cowl latch lever

b b - Cowl latch seal

11612

6. Insert the cowl latch pivot rod into the cowl latch. The cowl latch pivot rod end with two holes must be on the starboard side
of the cowl.
7. Push the cowl latch pivot rod through the cowl latch lever and the cowl latch seal.
8. Center the cowl latch pivot rod bolt holes with the lower cowl threaded holes.
9. Install four washers (two each side) between the cowl latch pivot rod and the lower cowl.
NOTE: Some models do not have washers between the cowl latch pivot rod and the lower cowl.

b a - Washer (4)
b - Cowl latch pivot rod two holes

a
11615

10. Install the cowl latch pivot rod detent spring and bolts. Tighten the bolts to the specified torque.

a a - Bolt securing cowl latch pivot rod (2)

b - Cowl latch detent spring
c - Cowl latch lever

c 11610

Description Nm lb. in. lb. ft.

Bolt securing cowl latch pivot rod (2) 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-17

Service Procedures

High Pressure Fuel Filter

High Pressure Fuel Filter Removal
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

! CAUTION
Failure to release pressure from the fuel system will result in fuel spraying out, which can cause a fire or explosion. Allow the
engine to cool completely and release all fuel pressure before servicing any part of the fuel system. Always protect eyes and
skin from pressurized fuel and vapors.

1. Disconnect the battery cable from the battery.

2. Install a fuel pressure gauge onto the fuel rail Schrader valve and release any pressurized fuel into an appropriate
container.

a - Schrader valve
a

10216

Fuel Pressure Gauge Kit 91‑881833A03

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1
Digital Pressure Meter 91‑892651A01
3. Remove the spring clamp securing the fuel hose to the high pressure fuel filter. Remove the fuel hose from the high
pressure fuel filter.
4. Remove the bolt securing the high pressure fuel filter bracket to the cylinder block.

c a- Spring clamp securing fuel hose

b- Oil filter
b
c- Bolt securing high pressure fuel filter bracket
d d- High pressure fuel filter
e- Water separating fuel filter

a
e
16852

5. Pull the high pressure fuel filter up and out of the cowl area.

Page 3C-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
6. Remove the fuel filter grommet and the fuel filter bracket from the high pressure fuel filter.
7. Remove the spring clamp securing the lower fuel hose to the high pressure fuel filter.

a - Fuel filter grommet

b - Fuel filter bracket
b c - Spring clamp

10248

High Pressure Fuel Filter Installation

1. Install the side of the high pressure fuel filter identified with the word "OUT" onto the lower fuel hose. Secure the lower fuel
hose with a spring clamp.

a - "IN"
a
b - "OUT"
c - Spring clamp securing fuel hose

b
c
10253

2. Install the fuel filter grommet.

3. Install the fuel filter bracket to the fuel filter grommet.

a - Fuel filter grommet

b - Fuel filter bracket
b

21176

4. Secure the fuel filter bracket to the cylinder block with a bolt. Tighten the bolt to the specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-19

Service Procedures
5. Install the fuel hose to the high pressure fuel filter. Secure the fuel hose to the high pressure fuel filter with a spring clamp.

c a- Spring clamp securing fuel hose

b- Oil filter
b
c- Bolt securing high pressure fuel filter bracket
d d- High pressure fuel filter
e- Water separating fuel filter

a
e
16852

Description Nm lb. in. lb. ft.

Bolt securing high pressure fuel filter bracket 6 53

Vapor Separator Tank (VST)

VST Removal
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

! CAUTION
Failure to release pressure from the fuel system will result in fuel spraying out, which can cause a fire or explosion. Allow the
engine to cool completely and release all fuel pressure before servicing any part of the fuel system. Always protect eyes and
skin from pressurized fuel and vapors.

1. Disconnect the battery cable from the battery.

2. Install a fuel pressure gauge onto the fuel rail Schrader valve and release any pressurized fuel into an appropriate
container.

a - Schrader valve
a

10216

Fuel Pressure Gauge Kit 91‑881833A03

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1

Page 3C-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Digital Pressure Meter 91‑892651A01

3. To access the VST drain hose, remove the two screws securing the lower cowl to the driveshaft housing.
4. Spread the lower cowl open and remove the cowl from the driveshaft housing.

a - Lower cowl screw (2)

10213

5. Use an appropriate container to capture fuel drained from the VST.

a - VST vent hose

b - VST drain hose
c - Fuel pressure regulator vent hose

c
b
10214
6. Open the VST drain screw and allow the VST to drain completely.

10217

7. Remove the hose clamp securing the fuel hose to the VST. Remove the fuel hose from the VST.
8. Remove the vent hose from the air vent assembly.
9. Disconnect the high pressure fuel pump wire harness connector.
10. Remove the two bolts securing the VST to the cylinder block.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-21

Service Procedures
11. Lift the VST off the lower VST mounting grommet.

b e a - Hose clamp (remove)

b - VST vent hose
c - High pressure fuel pump wire harness
c connector
a d - Bolts securing VST (2)
e - Air vent assembly

10222

12. Remove the fuel pressure regulator vent hose.

13. Remove the hose clamp securing the fuel return hose to the fuel pressure regulator.
14. Remove the fuel delivery hose from the VST.

a - Fuel pressure regulator vent hose

a b - Fuel return hose
b
c - Fuel delivery hose

9853

15. Lift the VST up to remove the VST drain hose from the bottom cowl.

20394

VST Disassembly
1. Remove the washers, grommets, and spacers from the VST assembly.
2. Remove the VST vent hose.

Page 3C-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
3. Remove the VST drain hose.

e f a- Spacer (2)
b- Grommet (2)
c- Grommet (2)
c d
b d- Washer (2)
e- VST vent hose
f- Assembled grommet
a g- VST drain hose

g
16735

4. Remove the two screws securing the fuel pressure regulator to the VST cover. Remove the fuel pressure regulator from
the VST cover.
5. Remove the five screws securing the VST cover to the VST tank.
6. Separate the cover from the tank.

a a - Screws securing fuel pressure regulator (2)

b - Screws securing VST cover (5)

10249

7. Push the fuel pressure regulator return tube assembly out of the VST cover.
8. Loosen the float pin screw. Remove the float and fuel inlet needle.

a - Fuel pressure regulator return tube

b - Float pin screw

10255

9. Pull the high pressure fuel pump from the VST cover.
10. Remove the insulator cover protecting the wires on the high pressure fuel pump.
11. Remove the wires on the high pressure fuel pump.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-23

Service Procedures
12. Remove the high pressure fuel pump grommet.

a - Insulator cover
b - High pressure fuel pump wires
b c - High pressure fuel pump grommet
a

10256

13. Remove the fuel filter and grommet from the fuel pump base.
14. Remove the fuel pump base from the high pressure fuel pump.

b c
a - Fuel filter
a b - Grommet
c - Fuel pump base

10259

15. Push on the high pressure fuel pump wire harness assembly retaining tabs to remove the wire harness assembly from the
VST cover.

a - Retaining tabs

10260

VST Reassembly
Fuel Pump Reassembly
1. Install the fuel pump base to the high pressure fuel pump.
2. Install the grommet to the fuel pump base.

Page 3C-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

3. Push the fuel filter onto the fuel pump base.

a b c d a - High pressure fuel

pump
b - Fuel pump base
c - Grommet
d - Fuel filter

10334

High Pressure Fuel Pump Wire Harness

1. Guide the wires through the VST cover opening.
2. Push the wire harness connector onto the VST cover. Ensure the connector is in proper alignment on the VST cover.

b a - VST cover
c b - Wire harness connector
c - Alignment pins on VST cover
a

10339

3. Ensure wire harness connector retaining tabs hold the connector into the VST cover.

a - Retaining tabs

10260

Fuel Inlet Needle And Float Installation

1. Install the fuel inlet needle clip.

a b a - Needle clip
b - Fuel inlet needle

10344

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-25

Service Procedures

2. Install the fuel inlet needle to the float.

10349

3. Insert the float pin through the float

4. Install the float/needle assembly onto the VST cover. Secure the float/needle assembly to the cover with float pin screw.
Tighten the float pin screw to the specified torque.

a a - Float
b - Float pin screw
c - Float pin

c 10351

Description Nm lb. in. lb. ft.

Float pin screw 4 35

High Pressure Fuel Pump Assembly Installation

1. Push the high pressure fuel pump grommet onto the VST cover. Ensure the high pressure fuel pump grommet is seated
and level on the VST cover.

10353

Page 3C-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

2. Install the black wire connector to the negative (‑) side of the high pressure fuel pump. Install the brown wire connector to
the positive (+) side of the high pressure fuel pump.

a - Brown wire ‑ positive (+)

b - Black wire ‑ negative (‑)
a

10355

3. Install the fuel pump wire insulator.

b a - Brown wire
b - Black wire
c - Fuel pump wire insulator

a
c

10356

4. Push fuel pump into the high pressure fuel pump grommet.

10357

VST Cover Installation

1. Install a new seal onto the VST tank.

10358

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-27

Service Procedures

2. Install new O‑rings onto the fuel pressure regulator return tube.

10359

3. Insert the fuel pressure regulator return tube into the VST cover assembly. Ensure the fuel pressure regulator return tube is
fully seated into the VST cover.

10361

4. Install a new seal onto the fuel pressure regulator.

10362

5. Install the VST cover to the VST tank. Secure VST cover to the VST tank with five screws. Tighten the screws to the
specified torque.

Page 3C-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

6. Install the fuel pressure regulator. Secure fuel pressure regulator with two screws. Tighten the screws to the specified
torque.

a a - Screws securing fuel pressure regulator (2)

b - Screws securing VST cover (5)

10249

Description Nm lb. in. lb. ft.

Fuel pressure regulator screw 6 53
VST cover screw 6 53

7. Install the VST mounting grommets to the VST.

8. Install the VST vent hose to the VST cover.
9. Install the VST drain hose.

e f a- Spacer (2)
b- Grommet (2)
c- Grommet (2)
c d
b d- Washer (2)
e- VST vent hose
f- Assembled grommet
a g- VST drain hose

g
16735

VST Installation
1. Insert the VST drain hose through the bottom cowl opening.

10324

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-29

Service Procedures
2. Ensure the VST drain hose is through the bottom cowl.

a - VST vent hose

b - VST drain hose
c - Fuel pressure regulator vent hose

c
b
10214
3. Install the smaller diameter hose to the fuel pressure regulator vent. Secure the hose with a spring clamp.
4. Install a 16.8 mm diameter hose clamp onto the fuel return hose. Install the fuel return hose onto the VST. Crimp the fuel
return hose clamp using the hose clamp tool.

Hose Clamp Tool Kit 91‑803146A04

5. Install the fuel delivery hose to the VST. Secure the fuel delivery hose with a spring clamp.

a - Fuel pressure regulator vent hose

a b - Fuel return hose
b
c - Fuel delivery hose

9853

6. Align the VST support with the grommet on the cylinder block and install the VST onto the grommet.

10325

7. Install a clamp onto a VST bolt. Install a washer onto the bolt. Install the bolt with the clamp and washer onto the upper
VST mounting grommet.
8. Install the remaining VST bolt and washer into the rear VST mounting grommet.
9. Tighten the VST bolts to the specified torque.

Page 3C-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
10. Connect the VST vent hose to the air vent assembly. Secure the VST vent hose to the air vent assembly with a spring
clamp.
11. Install a 16.8 mm diameter hose clamp onto the fuel hose and install the fuel hose to the VST. Crimp the fuel hose clamp
with a hose clamp tool.
12. Secure the engine wire harness, oil pressure sensor wire, crank position sensor wire, and high pressure fuel hose with the
clamp.
13. Connect the high pressure fuel pump wire harness connector to the high pressure fuel pump.

b e a- Hose clamp
b- Vent hose
c- High pressure fuel pump connector
c d- Bolts securing VST (2)
a e- Air vent assembly

10222

Description Nm lb. in. lb. ft.

Bolts securing the VST (2) 6 53

Hose Clamp Tool Kit 91‑803146A04

14. Prime the fuel system by turning the engine over with the lanyard switch in the "OFF" position. Check for leaks and repair
as needed.
15. Install the lower cowl to the driveshaft housing and secure with two screws.

a - Cowl screws (2)

10213

Fuel Cooler
Fuel Cooler Removal
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-31

Service Procedures

! CAUTION
Failure to release pressure from the fuel system will result in fuel spraying out, which can cause a fire or explosion. Allow the
engine to cool completely and release all fuel pressure before servicing any part of the fuel system. Always protect eyes and
skin from pressurized fuel and vapors.

1. Disconnect the battery cable from the battery.

2. Install a fuel pressure gauge onto the fuel rail Schrader valve and release any pressurized fuel into an appropriate
container.

a - Schrader valve
a

10216

Fuel Pressure Gauge Kit 91‑881833A03

Dual Fuel/Air Pressure Gauge Kit 91‑881834A 1
Digital Pressure Meter 91‑892651A01
3. Remove the clamp securing the fuel hose to the fuel cooler. Remove the fuel hose from the fuel cooler.
4. Remove the water pump indicator hose from the fuel cooler water exit port.
5. Remove the two bolts securing the fuel cooler to the fuel cooler bracket. Do not lose the gasket behind the fuel cooler.

a - Bolts securing fuel cooler to bracket (2)

b - Clamp securing fuel hose
c - Water pump indicator hose
a
c

10379

6. Pull the fuel cooler away from the mounting bracket.

7. Remove the fuel cooler water delivery hose.
8. Remove the clamp securing the fuel hose coming from the VST. Remove the fuel hose.

a a - Fuel hose coming from the VST

b - Fuel cooler water delivery hose

10380

Page 3C-32 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Fuel Cooler Disassembly and Reassembly

Fuel Cooler Disassembly
1. Remove the three cross flow plugs from the fuel cooler.

a - Cross flow plugs (3)

10498

2. Remove the four screws (two on each side) securing the fuel cooler end caps to the fuel cooler manifold.

10551

Fuel Cooler Reassembly

1. Use compressed air to remove debris from the fuel cooler manifold.
2. Install new O‑rings onto the fuel cooler end caps.

9833

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-33

Service Procedures

3. Install the end caps onto the fuel cooler manifold. Secure the end caps with two screws. Tighten the screws to the specified
torque.

10551

Description Nm lb. in. lb. ft.

End cap screws (4) 4 35

4. Install new O‑ring seals on the cross flow plugs.

5. Install the three cross flow plugs into the fuel cooler manifold. Torque the cross flow plugs to the specified torque.

a - Cross flow plugs (3)

b - Cross flow plug O‑ring (3)
a

b 11483

Description Nm lb. in. lb. ft.

Cross flow plugs (3) 6 53

Fuel Cooler Installation

1. Install the fuel cooler water delivery hose. The fuel cooler water delivery hose is connected to the lower starboard side of
the cylinder block. Secure the water delivery hose with a spring clamp.
2. Install a 16.8 mm diameter hose clamp onto the fuel hose coming from the VST. Secure the fuel hose coming from the
VST to the fuel cooler. Crimp the hose clamp using a hose clamp tool.

a a - Fuel hose coming from VST

b - Fuel cooler water delivery hose

10380

Page 3C-34 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

Hose Clamp Tool Kit 91‑803146A04

3. Install the gasket onto the back side of the fuel cooler.
4. Secure the fuel cooler to the fuel cooler mounting bracket with two bolts. Tighten the fuel cooler mounting bolts to the
specified torque.
5. Install a 16.8 mm diameter hose clamp to the fuel hose. Secure the fuel hose to the fuel cooler. Crimp the hose clamp
using a hose clamp tool.
6. Install the water pump indicator hose to the fuel cooler water exit port. Secure the water pump indicator hose to the fuel
cooler with a spring clamp.

a - Bolts securing fuel cooler to bracket (2)

b - Clamp securing fuel hose
c - Water pump indicator hose
a
c

10379

Description Nm lb. in. lb. ft.

Fuel cooler mounting bolt 6 53

Hose Clamp Tool Kit 91‑803146A2

Throttle Body
Throttle Body Removal
1. Remove the timing belt cover and the recoil assembly. Refer to Section 8 ‑ Manual Starter.
2. Remove the wire harness. Refer to Section 2B ‑ Engine Wire Harness.
3. Remove the IAC. Refer to Section 3C ‑ Idle Air Control (IAC).
4. Remove the two bolts securing the air horn to the bracket. Disconnect the crankcase breather hose and remove the air
horn from the throttle body.

a - Air horn
b - Crankcase breather hose
c - Bolts securing the air horn (2)
b
c

11517

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-35

Service Procedures
5. Disconnect the throttle actuating link from the throttle cam.

a - Throttle actuating link

b
b - Throttle cam

11519

6. Remove the air horn grommet.

7. Remove the two bolts securing the throttle body to the intake manifold. Remove the throttle body form the intake manifold.

a a - Bolts securing the throttle body

b - Air horn grommet

b
11536

Bracket Removal
1. Remove the four bolts securing the bracket to the powerhead.
2. Remove the bolt with the clamp securing the bracket to the powerhead.

a - Bolts securing bracket to powerhead

b - Bolt with a clamp securing bracket to
powerhead

b
a

11541

Throttle Body Disassembly and Reassembly

Throttle Body Disassembly
IMPORTANT: The throttle body, and the throttle position sensor (TPS) cannot be purchased separately. The throttle body is not
adjustable. If the TPS has failed, or the throttle butterfly adjustment screw was tampered with, a throttle body assembly must be
ordered.
1. Remove the bolt securing the throttle cam to the throttle body.

Page 3C-36 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

2. Remove the bolt, washer, throttle cam, bushing, washer, and spring from the throttle body.

11522

Throttle Body Assembly

1. Install a washer onto the bolt.
2. Install the throttle cam bushing into the throttle cam.
3. Install the bolt with the washer through the throttle cam bushing.
4. Install a washer onto the bolt.
5. Install the return spring onto the throttle body.

c
a b
d e f g

11538

a- Bolt
b- Washer
c- Throttle cam
d- Bushing
e- Washer
f- Return spring
g- Throttle body

6. Apply Loctite 242 Threadlocker to the bolt threads retaining the throttle cam to the throttle body.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-37

Service Procedures

7. Install the throttle cam to the throttle body. Secure the throttle cam with the bolt. Tighten the bolt to the specified torque.

11522

Description Nm lb. in. lb. ft.

Bolt 6 53

Tube Ref No. Description Where Used Part No.

66 Loctite 242 Threadlocker Bolt threads retaining the throttle cam to the throttle body 92-809821
8. Hook the return spring onto the throttle cam catch.
9. Move the throttle with the throttle cam to ensure there is no binding with the operation of the throttle butterfly.

a - Return spring hooked on throttle cam catch

a
11539

Throttle Body Installation

Bracket Installation
1. Align the bracket to the mounting holes on the cylinder block.
2. Install four bolts to secure the bracket to the cylinder block. Do not tighten the bolts at this time.
3. Install a bolt with a clamp, in the upper corner of the bracket, next to the starter mount.

Page 3C-38 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

4. Tighten all the bolts to the specified torque.

a - Bolts securing bracket to powerhead

b - Bolt with a clamp securing bracket to
powerhead

b
a

11541

Description Nm lb. in. lb. ft.

Bolts (5) 6 53

Throttle Body Installation

1. Install a gasket onto the intake manifold throttle body alignment pins.
2. Install the throttle body onto the intake manifold.
3. Secure the throttle body to the intake manifold with two bolts. Tighten the bolts to the specified torque.
4. Install the air horn grommet onto the throttle body.

a a - Bolts securing the throttle body

b - Air horn grommet

b
11536

Description Nm lb. in. lb. ft.

Bolts securing the throttle body 6 53

5. Connect the throttle actuating link to the throttle cam.

a - Throttle actuating link

b
b - Throttle cam

11519

6. Install the crankcase breather hose onto the air horn.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-39

Service Procedures

7. Install the air horn to the throttle body.

8. Secure the air horn to the bracket with two bolts. Tighten the bolts to the specified torque.

a - Air horn
b - Crankcase breather hose
c - Bolts securing the air horn (2)
b
c

11517

Description Nm lb. in. lb. ft.

Bolts securing the air horn (2) 6 53

9. Install the IAC. Refer to Section 3C ‑ Idle Air Control (IAC).

10. Install the wire harness. Refer to Section 2B ‑ Engine Wire Harness.
11. Install the timing belt cover and the recoil assembly. Refer to Section 8 ‑ Manual Starter.

Fuel Rail
Fuel Rail Removal
! WARNING
Performing service or maintenance without first disconnecting the battery can cause product damage, personal injury, or
death due to fire, explosion, electrical shock, or unexpected engine starting. Always disconnect the battery cables from the
battery before maintaining, servicing, installing, or removing engine or drive components.

! WARNING
Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot
start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated
and avoid prolonged exposure to vapors. Always check for leaks before attempting to start the engine, and wipe up any
spilled fuel immediately.

! CAUTION
Failure to release pressure from the fuel system will result in fuel spraying out, which can cause a fire or explosion. Allow the
engine to cool completely and release all fuel pressure before servicing any part of the fuel system. Always protect eyes and
skin from pressurized fuel and vapors.

1. Disconnect the battery cable from the battery.

Page 3C-40 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
2. Install a fuel pressure gauge to the fuel rail Schrader valve and release fuel into an appropriate container.

a - Schrader valve
a

10216

3. Open the fuel hose clamp to allow access to the fuel hose.

a- Fuel pump
b
b- Crankcase ventilation hose
c- Fuel hose clamp
d- Fuel rail
d

c
11634

4. Disconnect the fuel injector harness connectors from the three fuel injectors.
5. Remove the three bolts securing the fuel rail to the intake manifold. Do not lose the clamp on the top bolt securing the fuel
rail to the intake manifold.
6. Pull the fuel rail assembly off the intake manifold.

a - Fuel injector harness connector (3)

b - Fuel rail bolt (3)
c - Clamp
c

a
b

11635

7. Remove the spring clamp securing the fuel hose to the fuel rail inlet tube.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-41

Service Procedures
8. Remove the fuel hose from the fuel rail inlet tube. Clean up any spilled fuel after removing the fuel hose.

a - Fuel rail
b - Spring clamp

11636

Fuel Rail Disassembly

1. Remove the bolt securing the fuel inlet tube to the fuel rail. Remove the fuel inlet tube.
2. Remove the fuel injectors from the fuel rail.
3. Remove the screw securing the Schrader valve to the the fuel rail. Remove the Schrader valve.

a 11640

a - Bolt securing fuel inlet tube

b - Fuel inlet tube
c - Screw securing the Schrader valve

Fuel Rail Reassembly

1. Wash the fuel rail with a solvent. Use compressed air to clean and dry the fuel rail.
2. Install new O‑rings onto the fuel inlet tube.

a - O‑rings (2)

a
11643

3. Lubricate the fuel inlet tube O‑rings with 10W‑30 4‑Stroke Marine Engine Oil.
4. Install the fuel inlet tube onto the fuel rail.

Page 3C-42 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
5. Secure the fuel inlet tube to the fuel rail with a clamp and screw. Tighten the screw to the specified torque.

a - Screw
b - Inlet tube clamp
b

a
11645

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Fuel inlet tube O-rings 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

Screw 4 35
6. Install a new O‑ring onto the Schrader valve.

a
22560

7. Lubricate the Schrader valve O‑ring with 10W‑30 4‑Stroke Marine Engine Oil.
8. Install the Schrader valve onto the fuel rail. Secure the Schrader valve to the fuel rail with a clamp and screw. Tighten the
screw to the specified torque.

a - Schrader valve clamp

b - Screw

b
22563

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Fuel rail Schrader valve 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

Screw 4 35
9. Inspect the fuel injector filter.
NOTE: The fuel injector filter is a nonserviceable component but can be cleared of debris.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-43

Service Procedures
10. Install a new O‑ring and seal onto the fuel injectors.

b a - Filter
c b - O‑ring
c - Seal

22564

11. Lubricate the fuel injector O‑rings and seals with 10W‑30 4‑Stroke Marine Engine Oil.

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Fuel injector O-rings 92-8M0078625
Engine Oil
12. Install the fuel injectors onto the fuel rail. Ensure the fuel injector tab is properly located on the fuel rail.

a - Fuel rail
b - Fuel injector
b c - Fuel injector tab

c
22565

Fuel Rail Installation

1. Install the fuel hose to the fuel rail inlet tube.
2. Secure the fuel hose with a spring clamp.

a - Fuel rail
b - Spring clamp

11636

3. Lubricate the fuel injector seals with a light oil.

4. Install the fuel rail assembly to the intake manifold.
5. Secure the fuel rail to the intake manifold with three bolts. Tighten the bolts to the specified torque.

Page 3C-44 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
6. Connect the fuel injector harness connectors to the fuel injectors.

a - Fuel injector harness connector (3)

b - Fuel rail bolt (3)
c - Clamp
c

a
b

11635

Description Nm lb. in. lb. ft.

Fuel rail bolt 6 53
7. Close the clamp around the high pressure fuel line.
8. Install the crankcase ventilation hose to the cylinder head cover.
9. Secure the crankcase ventilation hose with a spring clamp.

a- Fuel pump
b
b- Crankcase ventilation hose
c- Fuel hose clamp
d- Fuel rail
d

c
11634

Intake Manifold
Intake Manifold Removal
1. Remove the engine harness. Refer to Section 2B ‑ Engine Wire Harness.
2. Remove the voltage regulator. Refer to Section 2B ‑ Battery Charging System.
3. Remove the ECM. Refer to Section 2A ‑ Ignition Components.
4. Remove the throttle body. Refer to Section 3C ‑ Throttle Body.
5. Remove the IAC. Refer to Section 3C ‑ Idle Air Control (IAC).
6. Remove the fuel rail. Refer to Section 3C ‑ Fuel Rail.
7. Remove the six bolts securing the intake manifold to the cylinder block and cylinder head.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-45

Service Procedures
8. Remove the three nuts and washers securing the intake manifold to the cylinder head intake manifold mounting studs.
Remove the intake manifold and the intake manifold insulator from the cylinder head.

10579

a - Nut and washers (3)

b - Bolts (6)

9. Remove the three bolts securing the ECM mounting bracket to the intake manifold.

a - Bolts securing the ECM mounting bracket (3)

11168

Intake Manifold Installation

1. Install the three grommets onto the ECM mounting bracket.
NOTE: The larger end of the grommet must face the rear of the ECM mounting bracket.
2. Install the spacers inside the three grommets.
3. Install the washer onto the three grommets.

a- Washer (3)
a b c d b- Spacer (3)
c- Grommet (3)
d- ECM mounting bracket

11170

Page 3C-46 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
4. Install the ECM mounting bracket to the intake manifold. Secure the ECM mounting bracket to the intake manifold with
three bolts and washers. Tighten the bolts to the specified toque.

a - Bolts securing the ECM mounting bracket (3)

11168

Description Nm lb. in. lb. ft.

Bolts securing the ECM mounting bracket (3) 6 53

5. Install 6 (three per side) O‑ring seals onto the intake manifold insulator.

11187

6. Install the intake manifold insulator onto the cylinder head intake manifold mounting studs.
7. Install the intake manifold onto the cylinder head intake manifold mounting studs.
8. Secure the intake manifold to the cylinder head with three washers and nuts. Do not tighten the nuts at this time.
9. Secure the intake manifold to the cylinder head and cylinder block with six bolts.
10. Tighten the 6 bolts and three nuts in sequence to the specified torque.

5 9

3 7
1

2 8

4
11469
6

Description Nm lb. in. lb. ft.

Nuts and bolts securing the intake manifold ( 6 bolts, three nuts,) 9 80

11. Install the fuel rail. Refer to Section 3C ‑ Fuel Rail.

12. Install the IAC. Refer to Section 3C ‑ Idle Air Control (IAC).

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-47

Service Procedures
13. Install the throttle body. Refer to Section 3C ‑ Throttle Body.
14. Install the engine harness. Refer to Section 2B ‑ Engine Wire Harness.
15. Install the ECM. Refer to Section 2A ‑ Ignition Components.
16. Install the voltage regulator. Refer to Section 2B ‑ Battery Charging System.

Idle Air Control (IAC)

The Idle Air Control (IAC) is an electrically operated spring‑loaded solenoid valve which controls the amount of air bypassing
the closed throttle shutter. Signals from the ECM regulate the duty cycle that the IAC valve remains open or closed. The duty
cycle ranges from 0% to 100% open.

IAC Removal
NOTE: Refer to Section 2B ‑ Engine Wire Harness to remove the engine wire harness.
1. Remove the green and blue trim motor wires from the down and up solenoids.

a - Green trim motor wire

a b b - Blue trim motor wire

20837

2. Remove the nut securing the two ground wires to the trim up solenoid. Remove the ground wires from the trim up solenoid.
3. Remove the bolt securing the two solenoid ground wires and the starter relay ground wire.
4. Remove the bolt securing the support bracket to the electrical bracket.

a - Nut securing the two ground wires

a b b - Bolt securing the two solenoid ground
wires, and the starter relay ground wire
c - Bolt securing the support bracket

c 20897

Page 3C-48 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
5. Remove the bolt securing the support bracket to the electrical bracket. Remove the support bracket.

20898

6. Remove two hoses connected to the IAC valve.

7. Remove three bolts and washers securing the IAC bracket to the support bracket.

a
b

a c

10598

a - IAC hoses
b - Upper IAC bracket bolts and washers (2)
c - Lower IAC bracket bolt and washer (1)

8. Remove the nut and washer securing the IAC valve to the IAC bracket.

10599

Remove the IAC filter from the electrical bracket.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-49

Service Procedures

20899

IAC Installation
1. Install the IAC filter onto the electrical bracket.

20899

2. Secure the IAC to the IAC bracket with a washer and nut. Tighten the nut to the specified torque.

10599

Description Nm lb. in. lb. ft.

IAC nut 10 88.5

3. Secure the IAC bracket to the electrical bracket with three bolts, washers, and rubber grommets. Tighten the bolts to the
specified torque.

Page 3C-50 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures
4. Install the IAC hoses to the IAC. Secure IAC hoses to the IAC with spring clamps.

a
b

a c

10598

a - IAC hoses
b - Upper IAC bracket bolts and washers (2)
c - Lower IAC bracket bolts and washer (1)

Description Nm lb. in. lb. ft.

IAC bracket bolt 6 53

5. Install the support bracket to the electrical bracket.

6. Secure the support bracket to the electrical bracket with a bolt and washer. Tighten the bolt to the specified torque.

20898

Description Nm lb. in. lb. ft.

Support bracket bolt 6 53
7. Secure the support bracket to the electrical bracket with a bolt and washer. Tighten the bolt to the specified torque.
8. Install the two solenoid ground wires and the starter relay ground wire onto the support bracket bolt. Secure the support
bracket with the bolt and ground wires. Tighten the bolt to the specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-51

Service Procedures
9. Install the two ground wires to the trim up solenoid. Secure the ground wires to the trim up solenoid with a lockwasher and
nut. Tighten the nut to the specified torque.

a - Ground wire nut and lockwasher

a b b - Solenoid and starter relay ground wire
bolt
c - Support bracket bolt

c 20897

Description Nm lb. in. lb. ft.

Support bracket bolt 6 53
Solenoid and starter relay ground wire bolt 6 53
Ground wire nut and lockwasher 6 53
10. Install the green and blue trim motor wires to the up and down trim solenoids. Secure the green and blue trim motor wires
with a lockwasher and nut. Tighten the nut to the specified torque.

a - Green trim motor wire

a b b - Blue trim motor wire

20837

Description Nm lb. in. lb. ft.

Nut 6 53
11. Install the engine wire harness. Refer to Section 2B ‑ Engine Wire Harness.

Wire Color Code Abbreviations

Wire Color Abbreviations
BLK Black BLU Blue
BRN Brown GRY or GRA Gray
GRN Green ORN or ORG Orange
PNK Pink PPL or PUR Purple
RED Red TAN Tan
WHT White YEL Yellow
LT or LIT Light DK or DRK Dark

Page 3C-52 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Service Procedures

IAC Test
The operation of the IAC can be measured with the CDS tool and adapter harnesses.

a - ECM engine harness

connector
b - Idle Air Control (IAC)
GRN/RED
c - Vapor Separator Tank
BLU (VST)

BLU/BLK
BLU
a

18 1
1 BLU

22 BLU/BLK

16 GRN/RED

22594
34 17

CDS G3 Diagnostic Tool Kit 8M0114141

Adapter Harness 84‑899150T01
Adapter Harness 84‑822560A7
Extension Cable 84‑825003A 1

1. Apply 69 kPa (10 PSI) vacuum to the top port of the IAC.
2. Ensure the IAC holds the vacuum pressure.
3. Apply 12 volts to the terminals of the IAC.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 3C-53

Service Procedures
4. If the vacuum pressure is not released when 12 volts is applied to IAC terminals, replace the IAC.

a - 12 volts positive
b - 12 volts negative

a b

22595

5. Measure the resistance of the IAC with the DMT 2004 Digital Multimeter tool. The IAC is not polarity sensitive.
NOTE: The IAC resistance values are for reference only.

Meter Test Leads

Meter Scale Reading (O)
Red Black
Right terminal pin Left terminal pin Auto 24.0 ‑ 30.0
6. Connect the DMT 2004 Digital Multimeter tool to the terminal pins of the IAC.

23017

DMT 2004 Digital Multimeter 91‑892647A01

Page 3C-54 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Emissions

Fuel System
Section 3D - Emissions
Table of Contents

3
Exhaust Emission Standards.............................................3D-2 Dealer Responsibility..................................................3D-3
What Are Emissions?................................................. 3D-2 Owner Responsibility..................................................3D-3
Hydrocarbons – HC.................................................... 3D-2 Exceptions.................................................................. 3D-3
Carbon Monoxide – CO.............................................. 3D-2
Oxides of Nitrogen – NOx...........................................3D-2
EPA Emission Regulations.........................................3D-3
Manufacturer's Certificate Label........................................ 3D-3
D
Controlling Emissions................................................. 3D-2 Service Replacement Certification Label...........................3D-3
Stoichiometric (14.7:1) Air/Fuel Ratio.........................3D-2 Removal..................................................................... 3D-3
Emissions Information....................................................... 3D-2 Date Code Identification............................................. 3D-4
Manufacturer's Responsibility.....................................3D-2 Installation.................................................................. 3D-4

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Emissions

Exhaust Emission Standards

Through the Environmental Protection Agency (EPA), the federal government has established exhaust emissions standards for
all new marine engines sold in the U.S.

What Are Emissions?

Emissions are what comes out of the exhaust system in the exhaust gas when the engine is running. They are formed as a
result of the process of combustion or incomplete combustion. To understand exhaust gas emissions, remember that both air
and fuel are made of several elements. Air contains oxygen and nitrogen among other elements; gasoline contains mainly
hydrogen and carbon. These four elements combine chemically during combustion. If combustion were complete, the mixture
of air and gasoline would result in these emissions: water, carbon dioxide and nitrogen, which are not harmful to the
environment. But combustion is not usually complete. Also, potentially harmful gases can be formed during and after
combustion.
All marine engines must reduce the emission of certain pollutants, or potentially harmful gases, in the exhaust to conform with
levels legislated by the EPA. Emissions standards become more stringent each year. Standards are set primarily with regard to
three emissions: hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx).

Hydrocarbons – HC
Gasoline is a hydrocarbon fuel. The two elements of hydrogen and carbon are burned during combustion in combination with
oxygen. But they are not totally consumed. Some pass through the combustion chamber and exit the exhaust system as
unburned gases known as hydrocarbons.

Carbon Monoxide – CO
Carbon is one of the elements that make up the fuel burned in the engine along with oxygen during the combustion process. If
the carbon in the gasoline could combine with enough oxygen (one carbon atom with two oxygen atoms), it would come out of
the engine in the form of carbon dioxide (CO2). CO2 is a harmless gas. But carbon often combines with insufficient oxygen
(one carbon atom with one oxygen atom). This forms carbon monoxide, CO. Carbon monoxide is the product of incomplete
combustion and is a dangerous, potentially lethal gas.

Oxides of Nitrogen – NOx

NOx is a slightly different by‑product of combustion. Nitrogen is one of the elements that makes up the air going into the
engine. Under extremely high temperatures it combines with oxygen to form oxides of nitrogen (NOx). This happens in the
engine's combustion chambers when temperatures are too high. NOx itself is not harmful, but when exposed to sunlight it
combines with unburned hydrocarbons to create the visible air pollutant known as smog. Smog is a serious problem in
California as well as many other heavily populated areas of the United States.

Controlling Emissions
There are two principle methods of reducing emissions from a two‑stroke‑cycle marine engine. The first method is to control the
air/fuel ratio that goes into the combustion chamber. The second is to control the time when this air/fuel mixture enters the
combustion chamber. Timing is important, to prevent any unburned mixture from escaping out of the exhaust port.

Stoichiometric (14.7:1) Air/Fuel Ratio

In the search to control pollutants and reduce exhaust emissions, engineers have discovered that they can be reduced
effectively if a gasoline engine operates at an air/fuel ratio of 14.7:1. The technical term for this ideal ratio is stoichiometric. An
air/fuel ratio of 14.7:1 provides the best control of all three elements in the exhaust under almost all conditions. The HC and CO
content of the exhaust gas is influenced significantly by the air/fuel ratio. At an air/fuel ratio leaner than 14.7:1, HC and CO
levels are low, but with a ratio richer than 14.7:1 they rise rapidly. It would seem that controlling HC and CO by themselves
might not be such a difficult task; the air/fuel ratio only needs to be kept leaner than 14.7:1. However, there is also NOx to
consider.
As the air/fuel ratio becomes leaner, combustion temperatures increase. Higher combustion temperatures raise the NOx
content of the exhaust. But, enrichening the air/fuel ratio to decrease combustion temperatures and reduce NOx also increases
HC and CO, as well as lowering fuel economy. So the solution to controlling NOx ‑ as well as HC and CO ‑ is to keep the air/
fuel ratio as close to 14.7:1 as possible.

Emissions Information
Manufacturer's Responsibility
Beginning with 1998 model year engines, manufacturers of all marine propulsion engines must determine the exhaust emission
levels for each engine horsepower family and certify these engines with the United States Environmental Protection Agency
(EPA). A certification decal/emissions control information label, showing emission levels and engine specifications directly
related to emissions, must be placed on each engine at the time of manufacture.

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 Emissions

Dealer Responsibility
When performing service on all 1998 and newer outboards that carry a certification, attention must be given to any adjustments
that are made that affect emission levels.
Adjustments must be kept within published factory specifications.
Replacement or repair of any emission related component must be executed in a manner that maintains emission levels within
the prescribed certification standards.
Dealers are not to modify the engine in any manner that would alter the horsepower or allow emission levels to exceed their
predetermined factory specifications.
Exceptions include manufacturer's prescribed changes, such as that for altitude adjustments.

Owner Responsibility
The owner/operator is required to have engine maintenance performed to maintain emission levels within prescribed
certification standards.
The owner/operator is not to modify the engine in any manner that would alter the horsepower or allow emission levels to
exceed their predetermined factory specifications.

Exceptions
• Carburetor jets may be changed for high altitude use in accordance with factory recommendations.
• Single engine exceptions may be allowed with permission from the EPA for racing and testing.

EPA Emission Regulations

All new 1998 and newer outboards manufactured by Mercury Marine for operation in the USA, are certified to the United States
Environmental Protection Agency as conforming to the requirements of the regulations for the control of air pollution from new
outboard motors. This certification is contingent on certain adjustments being set to factory standards. For this reason, the
factory procedure for servicing the product must be strictly followed and, whenever practicable, returned to the original intent of
the design.
The responsibilities listed above are general and in no way a complete listing of the rules and regulations pertaining to the EPA
laws on exhaust emissions for marine products. For more detailed information on this subject, you may contact the following
location:
EPA INTERNET WEB SITE: http://www.epa.gov/otaq/marinesi.htm

Manufacturer's Certificate Label

The certification label must be placed on each engine at the time of manufacture and must be replaced in the same location if
damaged or removed. Shown below is a typical certification label and is not representative of any one model. Label shown
below is not to scale.

a EMISSION CONTROL INFORMATION b

THIS ENGINE CONFORMS TO CALIFORNIA AND U.S. EPA
a- Date of manufacture
k JAN EMISSION REGULATIONS FOR SPARK IGNITION MARINE ENGINES. JUL
c b- Kilowatt hour (horsepower)
AND IS CERTIFIED TO g/kW-hr HC+N0x ENGINE FAMILY
j FEB EXHAUST EMISSION STANDARD IN CALIFORNIA AUG c- Piston displacement
MAR REFER TO OWNER’S MANUAL FOR REQUIRED MAINTENANCE
SPECIFICATIONS AND ADJUSTMENTS kW ml
SEP d d- Maximum emissions output for the engine
i APR FAMILY: U.S. EPA FEL: g/kw-hr OCT family
IDLE SPEED (IN GEAR)
MAY VALVE CLEARANCE (COLD) mm INTAKE:
TIMING:
NOV
e e- Timing specifications
EXHAUST:
h SPARK PLUG: GAP: HP DEC f- Horsepower rating
JUN
MERCURY MARINE f
g g- Emission label part number
23403
h- Recommended spark plug and gap
i- Valve clearance
j- Idle speed
k- Family number

Service Replacement Certification Label

IMPORTANT: By federal law, it is required that all 1998 and newer Mercury Marine outboards have a visible and legible
emission certification label. If this label is missing or damaged, contact Mercury Marine Service for a replacement.

Removal
Remove all remaining pieces of the damaged or illegible label. Do not install new label over the old label. Use a suitable solvent
to remove any traces of the old label adhesive from the display location.

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Emissions

Date Code Identification

Cut and remove a "V" notch through the month of engine manufacture before installing the new label. The month of
manufacture can be found on the old label. If the label is missing or the date code illegible, contact Mercury Marine Technical
Service for assistance.

Emission Control a - "V" notch

Information b - Month of
manufacture
THIS ENGINE CONFORMS TO (YEAR) CALIFORNIA AND U.S. EPA
EMISSION REGULATIONS FOR SPARK IGNITION MARINE ENGINES
REFER TO OWNERS MANUAL FOR MAINTENANCE,
SPECIFICATIONS, AND ADJUSTMENTS
IDLE SPEED (in gear): XXX RPM FAMILY: -----.XXXXXX
XXX HP XXXX cc FEL: XX.XXXX g/kWh
TIMING (IN DEGREES): XXXXXXXXX
PART NO. SPARK PLUG: XXXXXXXX
37-XXXXXX GAP: X.X MM (X.X IN.)
COLD VALVE INTAKE: 0.XX - 0.XX MM
CLEARANCE (mm) EXHAUST: 0.XX - 0.XX MM
JAN FEB MAR APR MAY JUNE JULY AUG SEP OCT NOV DEC b

a 11184

Installation
Install the label on a clean surface in the original factory location.

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 Cylinder Block/Crankcase

Powerhead
Section 4A - Cylinder Block/Crankcase
Table of Contents
Cylinder Block/Crankcase Specifications...........................4A-2 Cleaning/Inspection/Repair .............................................4A-14
Piston Specifications..........................................................4A-2 Measuring Cylinder Bore.......................................... 4A-14
Cylinder Block Components...............................................4A-4 Measuring Piston...................................................... 4A-15
Crankshaft, Piston, And Connecting Rod Components..... 4A-6 Crankcase Main Bearings.........................................4A-17
Powerhead Removal..........................................................4A-8 Connecting Rod Oil Clearance................................. 4A-19
Powerhead Components Removal ................................. 4A-10
Cylinder Block Disassembly.............................................4A-11
Cylinder Block Assembly................................................. 4A-20
Piston Installation......................................................4A-20 4
Crankcase Disassembly........................................... 4A-11
Flywheel...........................................................................4A-14
Crankshaft Installation.............................................. 4A-21
Thermostat and Anode Installation........................... 4A-23 A
Crankshaft Drive Gear..................................................... 4A-14 Powerhead Reassembly...........................................4A-24
Timing Belt....................................................................... 4A-14 Powerhead Installation.....................................................4A-27
Anode...............................................................................4A-14

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Cylinder Block/Crankcase

Cylinder Block/Crankcase Specifications

Cylinder Block/Crankcase Specifications
Number of cylinders 3
Displacement 526 cc (32.09 cu. in.)
Standard bore 61.0 mm (2.4016 in.)
Standard bore (service limit) 61.06 mm (2.4039 in.)
Cylinder bore maximum taper (service limit) 0.08 mm (0.0032 in.)
Cylinder bore maximum out of round (service limit) 0.06 mm (0.0024 in.)
Crankshaft main bearing journal 35.99 mm (1.4169 in.)
Crankshaft main bearing journal (service limit) 35.97 mm (1.4161 in.) or less
Crankshaft pin journal 29.98 mm (1.1803 in.)
Crankshaft pin journal (service limit) 29.95 mm (1.179 in.) or less
Crankshaft end play 0.05–0.15 mm (0.002–0.006 in.)
Crankshaft runout Less than 0.05 mm (0.002 in.)
Crankshaft runout (service limit) 0.05 mm (0.002 in.) or more
Crankshaft main bearing oil clearance 0.012–0.044 mm (0.0005–0.0017 in.)
Crankshaft main bearing oil clearance (service limit) 0.06 mm (0.002 in.) or more
Crankshaft pin bearing oil clearance 0.010–0.036 mm (0.00037–0.00142 in.)
Crankshaft pin bearing oil clearance (service limit) 0.060 mm (0.002 in.) or more
Connecting rod wrist pin bore diameter 16.01–16.04 mm (0.630–0.631 in.)
Connecting rod wrist pin bore diameter (service limit) 16.04 mm (0.631 in.) or more
Connecting rod crankshaft pin diameter 29.995–30.021 mm (1.1809–1.1819 in.)
Connecting rod crankshaft pin diameter (service limit) 30.023 mm (1.182 in.) or more
Connecting rod side clearance 0.1–0.25 mm (0.004–0.01 in.)
Connecting rod side clearance (service limit) 0.6 mm (0.0236 in.)

Piston Specifications
Piston Specifications
Piston skirt standard diameter 60.96 mm (2.40 in.)
Piston skirt standard diameter (service limit) 60.90 mm (2.3976 in.)
Piston to bore clearance 0.020–0.055 mm (0.0008–0.0022 in.)
Wrist pin diameter 16.0 mm (0.63 in.)
Wrist pin diameter (service limit) 15.97 mm (0.629 in.)
Top ring side clearance 0.04–0.08 mm (0.0016–0.0031 in.)
Top ring side clearance (service limit) 0.1 mm (0.004 in.)
Second ring side clearance 0.03–0.07 mm (0.0012–0.0028 in.)
Second ring side clearance (service limit) 0.09 mm (0.0035 in.)
Oil ring side clearance 0.05–0.15 mm (0.002–0.0059 in.)
Oil ring side clearance (service limit) 0.17 mm (0.0067 in.)
Top ring end gap 0.15–0.30 mm (0.0059–0.0118 in.)
Top ring end gap (service limit) 0.5 mm (0.02 in.)
Second ring end gap 0.35–0.50 mm (0.0138–0.0197 in.)
Second ring end gap (service limit) 0.7 mm (0.028 in.)
Oil ring end gap 0.2–0.7 mm (0.008–0.028 in.)

Lubricants, Sealants, Adhesives

Tube Ref No. Description Where Used Part No.
Loctite 567 PST Pipe Oil pressure switch threads
9 92-809822
Sealant Water temperature sender threads

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 Cylinder Block/Crankcase

Tube Ref No. Description Where Used Part No.

Crankcase cover bolt threads
Piston, piston rings, and cylinder bore
10W-30 4-Stroke Marine Connecting rod and crankshaft main bearings
110 92-8M0078625
Engine Oil Main bearing bolt and perimeter bolt threads
Flange screw O-ring
Cylinder head cover seal
135 Three Bond 1217F Cylinder block crankcase mating surface 92-858005K02

Special Tools
Piston Ring Compressor FT2997

Compresses the piston rings to ease piston installation

8745

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Cylinder Block/Crankcase

Cylinder Block Components

9 11
9
1 10

12 13
2 14

15
16
17 18
19
7 20
6
8
2

3 5
4 22
21

27

24
23
25
24

26
12907

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 Cylinder Block/Crankcase

Cylinder Block Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Cylinder block assembly
2 2 Dowel pin
First Torque 10 88.5
3 8 Bolt
Final Torque 23.5 17
First Torque 6 53
4 8 Bolt
Final Torque 11.5 101.8
5 8 Washer
6 1 Oil filter bolt 30 22
7 1 Starter lock cable bracket
8 1 Bolt 6 53
9 3 Dowel pin
10 1 Lifting eye
11 2 Bolt 10 88.5
12 1 Thermostat
13 1 Gasket
14 1 Cap
15 2 Bolt 6 53
16 1 Bolt (M6 x 16) 6 53
17 1 Anode
18 1 Gasket
19 1 Anode plug
20 2 Bolt (M6 x 20) 6 53
21 1 Oil filter 18 159.3
22 1 Gasket
23 1 Plunger 21 186
24 2 Clamp
25 1 Hose
26 1 Strainer
27 1 Dipstick

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Cylinder Block/Crankcase

Crankshaft, Piston, And Connecting Rod Components

10
10

12

3 11

10
2 5

6 9
12

8
7

12908

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 Cylinder Block/Crankcase

Crankshaft, Piston, And Connecting Rod Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Crankshaft
2 8 Bearing
3 1 Upper oil seal
4 1 Lower oil seal
5 1 Key
6 1 Key
7 3 Connecting rod
First torque 6 53
8 6 Bolt (M7 x 1.0)
Final torque 12 106
9 3 Piston
10 3 Piston ring set
11 3 Piston pin
12 6 Piston pin retainer

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Cylinder Block/Crankcase

Powerhead Removal
1. Disconnect the battery positive and negative cables from the battery.
2. Remove the remote control cables (if equipped).
3. Drain the oil sump into an appropriate container. Refer to Section 1B ‑ Maintenance.
4. Relieve the fuel pressure in the fuel rail. Refer to Section 3C ‑ Vapor Separator Tank (VST).
5. Remove the VST. Refer to Section 3C ‑ Vapor Separator Tank (VST).
6. Remove the engine wire harness. Refer to Section 2B ‑ Engine Wire Harness.
7. Remove the IAC. Refer to Section 3C ‑ Idle Air Control (IAC).
8. Disconnect the hose from the fuel inlet fitting.
9. Remove the water pump indicator hose from the fuel cooler.

a - Fuel inlet hose

b - Water pump indicator hose

11471

10. Disconnect the throttle actuating link from the throttle cam.
11. Remove the shift link from the horizontal shift shaft.

a a - Throttle actuating link

b - Shift link

b
11453

12. Remove two bolts securing the horizontal shift shaft bracket.

a - Bolts securing the horizontal shift shaft bracket (2)

b - Horizontal shift shaft

a
b

11178

13. Move the horizontal shift shaft to the starboard side to disengage the upper shift shaft from the horizontal shift shaft.

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 Cylinder Block/Crankcase
14. Remove the interlock cable from the horizontal shift shaft.

a - Interlock cable
a
b b - Upper shift shaft
c - Horizontal shift shaft

c
11180

15. Remove the crankcase ventilation hose.

20942

16. Remove the hose on top of the air vent assembly.

20943

17. Remove six bolts (three each side) securing the powerhead to the driveshaft housing.

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Cylinder Block/Crankcase
18. Lift the powerhead off the driveshaft housing.

a - Powerhead mounting bolts (3 each side)

20944

Powerhead Components Removal

1. Remove the two fuel hoses to the fuel pump.
2. Remove the fuel cooling hose from the cylinder block.
3. Remove the bolt securing the high pressure fuel filter to the powerhead.
4. Remove the fuel hose from the fuel rail.
5. Remove the two bolts securing the fuel cooler to the mounting bracket.
6. Remove the bracket securing the fuel filter to the powerhead.
7. Remove the intake manifold. Refer to Section 3C ‑ Service Procedures.
8. Remove the timing belt. Refer to Section 2C ‑ Timing, Synchronizing, and Adjustments.

k
h j
a
g
b
i

c f

e
b
d 20947

a- High pressure fuel return to the fuel pressure regulator

b- Fuel hose from the fuel pump pressure outlet
c- High pressure fuel filter
d- High pressure fuel hose to the fuel rail
e- Fuel hose to the fuel pump vacuum inlet
f- Fuel cooler water delivery hose from the cylinder block
g- Fuel filter
h- Fuel cooler
i- Fuel pump
j- Intake manifold
k- Timing belt

9. Remove the cylinder head. Refer to Section 4B ‑ Cylinder Head.

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 Cylinder Block/Crankcase

Cylinder Block Disassembly

1. Remove the flywheel. Refer to Section 2A ‑ Flywheel Removal.
2. Remove the cylinder head. Refer to Section 4B ‑ Cylinder Head Removal.
3. Remove the timing belt tensioner.
4. Install the crankshaft flywheel key.
5. Install the crankshaft holding tool.
6. Bend the tab on the washer and use a wrench to hold the camshaft drive gear nut while turning the crankshaft with the
crankshaft holding tool.

a d a- Flywheel key
b b- Camshaft drive gear nut
c- Camshaft drive gear
d- Timing belt tensioner

11588

7. Remove the drive gear from the crankshaft.

8. Remove the thermostat cover and the thermostat.
9. Remove the anode cover bolts. Remove the anode cover.

a - Thermostat cover bolts

b - Anode cover bolts.

11735

Crankcase Disassembly
1. Remove the starter lock cable bracket.

a - Starter lock cable bracket

11593

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Cylinder Block/Crankcase
2. Remove the eight perimeter bolts in the sequential order listed.

2 1

6 5

8 7

4 3
11597

3. Remove the eight main bearing bolts in the sequential order listed.

4 3

8 7

5 6

1 2
11626

4. Remove the crankcase cover.

5. Identify the connecting rod position with indelible ink or paint. Do not use a scribe or a punch for identification of the
connecting rod orientation.

I II III 11627

6. Remove the connecting rod cap bolts and the connecting rod caps.
IMPORTANT: Do not intermix the connecting rod caps with the connecting rods.
7. Remove the crankshaft.

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 Cylinder Block/Crankcase
8. Remove the crankshaft seals.

a - Crankshaft seals (2)

b - Connecting rod caps with bolts

a a

b 11603

9. Reinstall the connecting rod caps. Tighten the connecting rod cap bolts finger tight.

I II

11605

10. Push the piston and connecting rod assembly out of the cylinder block.

11606

11. Remove the main bearings from the cylinder block and crankcase cover.

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Cylinder Block/Crankcase
IMPORTANT: Do not interchange the main bearing location. If reusing the original bearings, ensure the bearings are
installed in their original locations.

a - Main bearings

11608

Flywheel
Inspect the flywheel keyway and teeth. Replace if damaged or worn.

3116

Crankshaft Drive Gear

Inspect the crankshaft drive gear. Replace if damaged or worn.

3117

Timing Belt
Inspect the timing belt. Replace if worn, stretched, or damaged.

3118

Anode
Replace the engine water jacket anode if partially consumed.

Cleaning/Inspection/Repair
Measuring Cylinder Bore
Measure the cylinder walls for taper, out of round, or excessive ridge at the top of the ring travel. This should be done with a
cylinder bore dial indicator or an inside micrometer. Carefully move the gauge up and down the cylinder bore to determine
taper. Turn the gauge to different points around the cylinder wall to determine the out of round condition.

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 Cylinder Block/Crankcase
The measurement for cylinder taper should be taken at three depth locations: 15 mm (0.6 in.), 35 mm (1.4 in.), and 55 mm
(2.2 in.).

a - 55 mm (2.2 in.)
b - 35 mm (1.4 in.)
c - 15 mm (0.6 in.)

c
b
a

3129

Cylinder Bore
Cylinder bore (standard) 61.00 mm (2.4016 in.)
Cylinder bore (service limit) 61.06 mm (2.4039 in.)
Out of round (service limit) 0.06 mm (0.0023 in.)
Taper (service limit) 0.08 mm (0.0032 in.)

Measuring Piston
Inspect piston wall for wear or damage. Replace piston if necessary.

Piston Diameter
1. Measure the piston at a point 9 mm (0.35 in.) from the bottom, 90° to the piston pin. Replace the piston if out of
specification.

a a - Piston diameter
b b - Measure point 9 mm (0.35 in.)

22022

Piston
Diameter (standard) 60.96 mm (2.4000 in.)
Diameter (service limit) 60.90 mm (2.3976 in.)
2. Measure the piston to cylinder clearance. If out of specification examine the piston and cylinder bore further to determine
repair/replacement.
The minimum piston to cylinder wall clearance is defined by the formula: Minimum cylinder bore measurement ‑ Maximum
piston diameter measurement = Piston to cylinder clearance.

Piston To Cylinder Wall Clearance

Minimum clearance 0.020–0.055 mm (0.00079–0.00217 in.)
Maximum clearance (service limit) 0.150 mm (0.00591 in.)

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Cylinder Block/Crankcase

Piston Ring Side Clearance

Measure piston ring side clearance. Replace the piston and rings if out of specification.

a a - Top ring
b - Middle ring
b c - Oil ring

c
22023

Piston Ring Side Clearance

Top "a" 0.04–0.08 mm (0.0016–0.0031 in.)
Top "a" (service limit) 0.10 mm (0.0039 in.)
Middle "b" 0.03–0.07 mm (0.0012–0.0028 in.)
Middle "b" (service limit) 0.09 mm (0.0035 in.)
Oil "c" 0.05–0.15 mm (0.002–0.0059 in.)
Oil "c" (service limit) 0.17 mm (0.0067 in.)

Piston Ring End Gap

Measure the piston ring end gap clearance. Replace the piston rings as a set if out of specification.
NOTE: The ring must be level for measurement. Push the ring 4 mm (0.157 in.) into the bore with the crown of a piston.

a - 4 mm (0.157 in.)

22024

Piston Ring End Gap

Top 0.15–0.30 mm (0.0059–0.0118 in.)
Top (service limit) 0.50 mm (0.0197 in.)
Middle 0.35–0.50 mm (0.0138–0.0197 in.)
Middle (service limit) 0.70 mm (0.0276 in.)
Oil 0.20–0.70 mm (0.0079–0.0276 in.)

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 Cylinder Block/Crankcase

Piston Wrist Pin Diameter Oil Clearance

Measure the piston pin bore diameter. Measure the wrist pin diameter. Subtract the wrist pin diameter from the piston pin
diameter to find the oil clearance of the wrist pin. Replace the piston if out of specification.

22025

Piston Pin Oil Clearance

Oil clearance 0.002–0.012 mm (0.00008–0.0005 in.)

Piston Pin
Measure the piston pin diameter. Replace the piston pin if out of specification.

22026

Piston Pin
Diameter 16.0 mm (0.6299 in.)
Diameter (service limit) 15.97 mm (0.629 in.)

Crankcase Main Bearings

Measure the crankshaft main bearing clearance as outlined in the following procedure. Replace the upper and lower bearings
as a set if out of specification.

Main Bearing Oil Clearance

Main bearing clearance 0.012–0.044 mm (0.0005–0.00173 in.)
Functional limit 0.060 mm (0.00236 in.)

CRANKSHAFT MAIN BEARING CLEARANCE MEASUREMENT

IMPORTANT: When installing the original main bearings, do not interchange the main bearings. Install the main bearings in
their original positions.
1. Ensure the mating surface on the crankcase cover and cylinder block is clear of debris.
2. Clean all the oil from the following areas:
• Main bearing surfaces on the cylinder block and crankcase cover
• Main bearings
• Crankshaft bearing surfaces
3. Install the main bearing halves into the cylinder block.
NOTE: Align each bearing projection with the notch in the cylinder block.
4. Place a piece of plastigauge onto each of the crankshaft bearing surfaces.

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Cylinder Block/Crankcase

NOTE: Do not put plastigauge over the oil hole on the bearing surface of the crankshaft.

a b

a b
11632

a - Bearing projection in the cylinder block notch

b - Plastigauge

5. Install the bearing halves into the crankcase cover.

NOTE: Align each bearing projection with the notch in the cylinder block.
6. Install the crankcase cover onto the cylinder block.
7. Lightly lubricate the eight crankcase cover bolt threads with 10W‑30 4‑Stroke Marine Engine Oil. Tighten the bolts in the
sequence shown on the crankcase cover to the specified torque.
IMPORTANT: Do not move the crankshaft until the measurement process has been completed.

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Crankcase cover bolt threads 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

Main bearing bolts (8) 24 17
8. Remove the crankcase cover bolts and the crankcase cover.
9. Measure the plastigauge at its maximum compressed width.

a a - Compressed plastigauge
b
b - Plastigauge scale

11637

10. If the oil clearance is out of specification limit, measure the inside diameter of the cylinder block and crankcase cover main
bearing journals.

SELECTING NEW MAIN BEARINGS

1. Locate the main bearing code on the cylinder block.

Page 4A-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Block/Crankcase

2. The journal size of the cylinder block is stamped with a code letter on the upper end of the cylinder block.

a - Main bearing journal letter code

3. Use the color coded main bearing that matches the main bearing code letters on the cylinder block.

3147

Cylinder Block Main Bearing Code

Code Letter Dimension Bearing Color
A 39–39.008 mm (1.53543–1.53575 in.) Blue
B 39.008–39.016 mm (1.53575–1.53606 in.) Red

Bearing Thickness
Code Letter Dimension Bearing Color
A 1.488–1.494 mm (0.05858–0.05882 in.) Blue
B 1.494–1.500 mm 0.05882–0.5906 in.) Red

Connecting Rod Oil Clearance

Measure the connecting rod oil clearance using the measurement steps outlined following.

Connection Rod
Oil Clearance 0.015–0.041 mm (0.0006–0.0016 in.)

Connecting Rod Oil Clearance Measurement

IMPORTANT: Do not interchange connecting rod caps. Reinstall connecting rod caps in their original positions.
1. Clean all the oil from the connecting rod bearing surfaces and connecting rod journals on the crankshaft.
2. Install the connecting rod to the crankshaft.
IMPORTANT: Install connecting rods in their original locations (#1, #2 and #3). Make sure that the "UP" mark on the
connecting rod cap faces towards the flywheel end of the crankshaft.
3. Place a piece of plastigauge on the crankpin journals.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-19

Cylinder Block/Crankcase

NOTE: Do not put the plastigauge over the oil hole in the bearing surface of the crankshaft.

a a - Plastigauge
b - Crankshaft oil hole

11644

4. Install the connecting rod cap and tighten the connecting rod cap bolts to specification.
IMPORTANT: Do not rotate the crankshaft while performing this measurement.

Description Nm lb. in. lb. ft.

First 6 53
Connecting rod cap bolt
Final 12 106
5. Remove the connecting rod cap.
6. Measure the plastigauge at its maximum compressed width.

a - Compressed plastigauge
b - Plastigauge scale
a b

11650

7. If the oil clearance is out of specification limit, measure the diameter of the connecting rod and crankpin journal. Replace
as needed.

Cylinder Block Assembly

Piston Installation
IMPORTANT: The cylinder bores must be clean before installing the pistons. Clean the bore with a light honing as necessary.
After honing, clean the cylinder bores with water and mild detergent. After cleaning, swab out the cylinder bores with engine oil
and a clean cloth. Wipe the cylinder bore with a clean dry cloth.
1. Lubricate the piston, rings, and cylinder bores with 10W‑30 4‑Stroke Marine Engine Oil.
2. Use a piston ring compressor tool to compress the piston rings.
3. Using the piston ring compressor tool, install the piston/connecting rod assembly into the cylinder block.
4. Push down on the piston compressor tool to ensure that the tool is firmly seated against the block.

Page 4A-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Block/Crankcase
5. Ensure the UP mark on the top of the piston is towards the flywheel. Push the piston down into the cylinder bore until the
rings have entered the cylinder.

a - Piston
a b - Ring compressor tool firmly seated against the cylinder block

b 21019

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Piston, piston rings, and cylinder bore 92-8M0078625
Engine Oil

Piston Ring Compressor FT2997

6. Repeat the procedure for the remaining cylinders.

Crankshaft Installation
1. Install crankshaft main bearings into the cylinder block and crankcase cover.
2. Lubricate the following areas generously with 4‑Stroke 10W‑30 Outboard Oil.
• Crankshaft seal and main bearing areas
• Crankshaft connecting rod journals
• Connecting rod bearing surfaces
• Connecting rod caps
3. Lubricate the upper and lower crankshaft seal lips with 10W‑30 4‑Stroke Marine Engine Oil. Slide the seals onto the
crankshaft ends.
4. Carefully place the crankshaft onto the crankshaft main bearings.
5. Ensure the crankshaft seals are centered in the seal area of the cylinder block.

110
a - Upper and lower crankshaft seals
a b - Crankshaft main bearings
a

b b

110 11733

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Connecting rod and crankshaft main bearings 92-8M0078625
Engine Oil
6. Assemble the connecting rods to the crankshaft and install the connecting rod caps.
7. Secure the connecting rod caps with two bolts. Tighten the connecting rod cap bolts in two steps to the specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-21

Cylinder Block/Crankcase

Description Nm lb. in. lb. ft.

First 6 53
Connecting rod cap bolts
Final 12 106
8. Clean the cylinder block crankcase mating surface and the crankcase cover mating surfaces of debris.
9. Apply a continuous 1 mm (0.040 in.) bead of Three Bond 1217F onto the cylinder block crankcase mating surface.

Tube Ref No. Description Where Used Part No.

135 Three Bond 1217F Cylinder block crankcase mating surface 92-858005K02
10. Ensure the crankshaft seals are centered in the cylinder block seal area.
11. Install the crankcase cover.
12. Lubricate the eight main bearing bolt threads, and the eight perimeter bolts threads with 10W‑30 4‑Stroke Marine Engine
Oil. Tighten the bolts in two steps in the sequence shown, to the specified torque.

5 6
15 16
1 2
11 12
4 3
9 10
13 14
8 7 11734

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Main bearing bolt and perimeter bolt threads 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

First 10 88.5
Main bearing bolts (8)
Final 23.5 17

Description Nm lb. in. lb. ft.

First 6 53
Perimeter bolts (8)
Final 11.5 101.8
13. Install starter lock cable bracket. Secure the starter lock cable bracket with a bolt. Tighten the bolt to the specified torque.

11593

Description Nm lb. in. lb. ft.

Starter lock cable bracket bolt 6 53
14. Install the drive gear key into the crankshaft.

Page 4A-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Block/Crankcase
15. Install the drive gear onto the crankshaft.
16. Install the plate, lockwasher, and nut onto the crankshaft.

c
d
b

11787

a- Timing mark
b- Alignment slots
c- Alignment tab
d- Crankshaft keyway

IMPORTANT: The plate outside edge is curved. Install the plate with the outside curved edge toward the flywheel.
17. Install the flywheel key. Install the crankshaft holding tool and tighten the drive gear nut to the specified torque.

Description Nm lb. in. lb. ft.

Drive gear nut 64 46
18. Bend the lockwasher up to drive gear nut.
19. Install the belt tensioner but do not tighten the bolt.

a d a- Flywheel key
b b- Cam drive gear nut
c- Cam drive gear
d- Belt tensioner

11588

Thermostat and Anode Installation

1. Install the thermostat, thermostat cover gasket, and thermostat cover. Secure the thermostat cover with two bolts.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-23

Cylinder Block/Crankcase
2. Install a new anode to the flange screw. Secure the anode with a screw. Tighten the anode screw to the specified torque.

a a- Flange screw
b c
d b- O‑ring
c- Anode
d- Screw

57328

Description Nm lb‑in. lb‑ft

Anode screw 6 53 –
3. Install a new O‑ring onto the flange screw.
4. Lubricate the O‑ring with 10W‑30 4‑Stroke Marine Engine Oil and install the flange screw onto the cylinder block.

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Flange screw O-ring 92-8M0078625
Engine Oil
5. Tighten the thermostat cover bolts and the anode flange screw to the specified torque.

a - Thermostat cover bolts (2)

b - Anode cover bolts (2)

11735

Description Nm lb. in. lb. ft.

Thermostat cover bolts (2) 6 53
Anode flange screw 6 53

Powerhead Reassembly
1. Install the cylinder head.Refer to Section 4B ‑ Cylinder Head Installation.
2. Coat the oil pressure switch threads with Loctite 567 PST Pipe Sealant.

Page 4A-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Block/Crankcase
3. Install the oil pressure switch. Tighten the oil pressure switch to the specified torque.

a - Oil pressure switch

a

11795

Tube Ref No. Description Where Used Part No.

Loctite 567 PST Pipe
9 Oil pressure switch threads 92-809822
Sealant

Description Nm lb. in. lb. ft.

Oil Pressure Switch 8 71
4. Coat the water temperature sender threads with Loctite 567 PST Pipe Sealant.
5. Install the water temperature sender. Tighten the water temperature sender to the specified torque.

a - Water temperature sender

11797

Tube Ref No. Description Where Used Part No.

Loctite 567 PST Pipe
9 Water temperature sender threads 92-809822
Sealant

Description Nm lb. in. lb. ft.

Water temperature sender 22 16.2
6. Install a key into the camshaft.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-25

Cylinder Block/Crankcase
7. Install the camshaft gear and secure with a washer and bolt. Tighten the bolt to the specified torque.

a - Camshaft gear bolt

a
11802

Description Nm lb. in. lb. ft.

Camshaft gear bolt 11 97
8. Install the timing belt. Refer to Section 2C ‑ Timing Belt Installation.
9. Adjust the valves. Refer to Section 4B ‑ Valve Adjustment.
10. Install a new seal in the cylinder head cover and lubricate the cylinder head seal with 10W‑30 4‑Stroke Marine Engine Oil.
11. Install the cylinder head cover. Tighten the cylinder head cover bolts in two steps to the specified torque.
12. Install the fuel pump. Tighten the bolts to the specified torque.

a - Cylinder head cover bolts (8)

b - Fuel pump bolts (2)

b
a a

11485

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Cylinder head cover seal 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

6 53
Cylinder Head Cover Bolts (8)
9 80
Fuel Pump Bolts (2) 6 53
13. Install the powerhead assembly onto the driveshaft housing. Refer to Powerhead Installation, following.
14. Install the fuel components. Refer to Section 3C ‑ Fuel System.
15. Install the electrical components. Refer to Section 2A ‑ Electrical.

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 Cylinder Block/Crankcase

Powerhead Installation
1. Install the fuel cooler bracket and the air vent bracket to the cylinder block. Secure the brackets with two bolts. Tighten the
bolts to the specified torque.

a - Bolts securing the fuel cooler bracket and the air vent bracket (2)

20955

Description Nm lb. in. lb. ft.

Bolts (2) 6 53

2. Install the intake manifold. Refer to Section 3C ‑ Service Procedures.

3. Install the high pressure fuel filter bracket. Tighten the bolt to the specified torque.

Description Nm lb. in. lb. ft.

Bolt 6 53
4. Install the high pressure fuel hose to the fuel rail. Secure the high pressure fuel hose with a spring clamp.
5. Install the fuel cooling hose onto the cylinder block.
6. Connect the fuel hose from the fuel filter outlet, to the fuel pump inlet.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-27

Cylinder Block/Crankcase
7. Connect the fuel hose to the fuel pump outlet.

k
h j
a
g
b
i

c f

e
b
d 20947

a- High pressure fuel return to the fuel pressure regulator

b- Fuel hose to the fuel pump pressure outlet
c- High pressure fuel filter
d- High pressure fuel hose to the fuel rail
e- Fuel hose to the fuel pump vacuum inlet
f- Fuel cooler water delivery hose to the cylinder block
g- Fuel filter
h- Fuel cooler
i- Fuel pump
j- Crankcase ventilation
k- Timing belt

8. Ensure the adapter plate surface and the powerhead mating surface is clear of debris.
9. Install a new powerhead gasket onto the adapter plate.
10. Install the powerhead onto the adapter plate.
11. Secure the powerhead to the adapter plate with six bolts (three each side). Tighten the powerhead mounting bolts to the
specified torque.

a - Powerhead mounting bolts (3 each side)

20944

Description Nm lb. in. lb. ft.

Powerhead mounting bolts (3 each side) 30 22

Page 4A-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Block/Crankcase
12. Install the air vent assembly to the bracket. Connect the air vent hose to the air vent assembly. Secure the air vent hose
with a spring clip.

20943

13. Install the crankcase ventilation hose to the valve cover. Secure the crankcase ventilation hose with a spring clip.

20942

14. Connect the interlock cable to the horizontal shift shaft.

15. Engage the upper shift shaft with the horizontal shift shaft.
16. Insert the horizontal shift shaft into the shift shaft bracket.

a- Interlock cable
a
b b- Upper shift shaft
d c- Horizontal shift shaft
d- Shift shaft bracket

c
20965

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4A-29

Cylinder Block/Crankcase
17. Secure the shift bracket to the cylinder block with two bolts. Tighten the bolts to the specified torque.

a - Bolts securing the horizontal shift shaft bracket (2)

b - Horizontal shift shaft

a
b

11178

Description Nm lb. in. lb. ft.

Bolts securing the horizontal shift shaft bracket (2) 6 53
18. Install the shift link to the horizontal shift shaft. Secure the the shift link to the horizontal shift shaft with a washer and cotter
pin.
19. Connect the throttle actuating link to the throttle cam.

a a - Throttle actuating link

b - Shift link

b
11453

Page 4A-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Powerhead
Section 4B - Cylinder Head
Table of Contents
Cylinder Head Specifications............................................. 4B-2 Cylinder Head Resurfacing.......................................4B-14
Cylinder Head Components...............................................4B-4 Valve Guides............................................................ 4B-15
Camshaft and Timing Belt Tensioner Components........... 4B-6 Valve Seat Reconditioning........................................4B-15
Intake and Exhaust Valve Components.............................4B-8 Cylinder Head Reassembly............................................. 4B-16
Cylinder Head Removal................................................... 4B-10 Valve Installation.......................................................4B-16
Cylinder Head Disassembly......................................4B-11
Cleaning and Inspection.................................................. 4B-13
Cam and Rocker Installation.....................................4B-17
Cylinder Head Installation................................................ 4B-19 4
Valves....................................................................... 4B-13
Valve Springs............................................................4B-14
Valve Adjustments........................................................... 4B-21
B

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Cylinder Head

Cylinder Head Specifications

Cylinder Head Specification
Maximum deck warp 0.1 mm (0.004 in.)
Number of valves 6
Number of valves per cylinder 2
Number of cams 1
Camshaft bearing outside diameter
Pulley side 17.98 mm (0.708 in.)
Pulley side (service limit) 17.95 mm (0.707 in.)
Oil pump side 15.97 mm (0.629 in.)
Oil pump side (service limit) 15.95 mm (0.628 in.)
Cam lobe height
(25) Intake and exhaust 23.87 mm (0.9398 in.)
(25) Intake and exhaust (service limit) 23.60 mm (0.9291 in.)
(30) Intake and exhaust 24.28 mm (0.9559 in.)
(30) Intake and exhaust (service limit) 24.0 mm (0.9449 in.)
Valve lash
Intake 0.13–0.17 mm (0.005–0.007 in.)
Exhaust 0.18–0.22 mm (0.007–0.008 in.)
Valve seat angles 30°, 45°, 60°
Valve spring free length 35 mm (1.38 in.)
Valve spring free length (service limit) 33.5 mm (1.319 in.)
Valve stem diameter
Intake 5.48 mm (0.216 in.)
Intake (service limit) 5.46 mm (0.215 in.)
Exhaust 5.46 mm (0.215 in.)
Exhaust (service limit) 5.44 mm (0.214 in.)
Valve face width (intake and exhaust) 1.0 mm (0.04 in.)
Valve face width (service limit) 2.0 mm (0.08 in.)
Valve seat width 1.0 mm (0.04 in.)
Valve guide bore
Intake and exhaust 5.51 mm (0.217 in.)
Intake valve guide bore (service limit) 5.55 mm (0.218 in.)
Exhaust valve guide bore (service limit) 5.57 mm (0.219 in.)
Valve stem to valve guide clearance
Intake 0.008–0.04 mm (0.0003–0.0016 in.)
Intake (service limit) 0.007 mm (0.0028 in.)
Exhaust 0.025–0.057 mm (0.001–0.0022 in.)
Exhaust (service limit) 0.1 mm (0.004 in.)
Rocker arm shaft outside diameter 12.99 mm (0.511 in.)
Rocker arm shaft outside diameter (service limit) 12.94 mm (0.509 in.)
Rocker arm inside diameter 13.01 mm (0.512 in.)
Rocker arm inside diameter (service limit) 13.05 mm (0.514 in.)
Rocker arm shaft clearance 0.006–0.035 mm (0.0003–0.0014 in.)
Cylinder head upper camshaft bearing inside diameter 18.01–18.025 mm (0.709–0.710 in.)
Oil pump camshaft bearing inside diameter 18.01–18.025 mm (0.709–0.710 in.)
Valve stem seal color
Intake Black
Exhaust Green

Page 4B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Lubricants, Sealants, Adhesives

Tube Ref No. Description Where Used Part No.
95 2-4-C with PTFE Camshaft seal lip 92-802859A 1
Valve stem
Camshaft, cylinder head and camshaft bearing surface
10W-30 4-Stroke Marine
110 Intake rocker shaft 92-8M0078625
Engine Oil
Exhaust rocker shaft
Cylinder head bolt threads

Special Tools
Valve Spring Compressor 91‑809494A1

Removes and installs valve springs.

3454

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-3

Cylinder Head

Cylinder Head Components

5 14
13 11
6

12

15

1 7
9
4 8

3 10

16

19
17
18
23

20
21 23
3 22
6

24

12904

Page 4B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Cylinder Head Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Cylinder head
2 1 Gasket
3 2 Dowel pin
4 3 Stud 10 88.5
5 1 Hose
6 3 Clip
First Torque 10 88.5
7 8 Bolt (M8 x 60)
Final Torque 30 22
8 1 Oil galley cover
9 8 Bolt (M6 x 12) 6 53
10 1 Cylinder head cover
11 1 Oil fill cap
12 1 O‑ring
First Torque 6 53
13 8 Bolt (M6 x 53)
Final Torque 9 80
14 1 Decal
15 1 Clamp
16 1 Gasket
17 3 Spark plug 18 159
18 1 Plug 12 106
19 1 Gasket
First Torque 6 53
20 3 Bolt (M6 x 53)
Final Torque 10 88.5
21 3 Washer
22 1 Plate
23 7 Bolt 6 53
24 1 Hose

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-5

Cylinder Head

Camshaft and Timing Belt Tensioner Components

13
14
12
11
15

9
16
17 10 8
7

18 7
6
19

20

21

5
4 21009

Page 4B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Camshaft and Timing Belt Tensioner Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Camshaft
2 1 Oil pump
3 1 Gasket
4 3 Bolt (M6 x 45) 9 80
5 3 Washer
6 1 Key
7 1 Camshaft seal
8 1 Camshaft gear
9 1 Bolt (M6 x 20) 11 97
10 1 Washer
11 1 Timing belt
12 1 Belt tensioner
13 1 Tensioner cover
14 1 Bolt (M10 x 40) 27 20
15 1 Washer
16 1 Spring
17 1 Hook
18 1 Nut 65 48
19 1 Lockwasher
20 1 Plate
21 1 Drive pulley

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-7

Cylinder Head

Intake and Exhaust Valve Components

10
11
16

9
8 8 18
7 10
15 11
6 6 7 8 9
5
4
10 16
5
11 16
16
3
8
9 18
11 10
15 2 9

16
1 10
11
16 18

9 11 10
9

15 16
17

14
12
13
14

16659

Page 4B-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Intake and Exhaust Valve Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 3 Intake valve
2 3 Exhaust valve
3 3 Intake valve stem seal (black)
4 3 Exhaust valve stem seal (green)
5 6 Seat
6 6 Spring
7 6 Retainer
8 12 Keeper
9 6 Rocker arm
10 6 Adjusting screw
11 6 Nut 7 62
12 1 Rocker arm shaft (intake)
13 1 Rocker arm shaft (exhaust)
14 2 Bolt 9 80
15 3 Spring
16 6 Washer
17 1 Spacer
18 3 Spring

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-9

Cylinder Head

Cylinder Head Removal

IMPORTANT: This engine utilizes an interference valve train design. Do not rotate the crankshaft or cams when the timing belt
is removed from the cam gears or crankshaft gear unless advised to do so. Failure to adhere to this caution may result in valve
and or piston damage.
1. Remove the powerhead. Refer to Section 4A ‑ Powerhead Removal.
2. Remove the timing belt. Refer to Section 2C ‑ Timing Belt Removal and Installation.
3. Remove the fuel rail and the intake manifold. Refer to Section 3C ‑ Service Procedures.
4. Remove the three oil pump retaining bolts.
5. Remove the oil pump.

a - Oil pump retaining bolts (3)

11499

6. Remove the cam gear retaining bolt.

7. Carefully pry on both sides of the cam gear to remove the cam gear from the camshaft.

a - Cam gear retaining bolt

b - Pry points

a
b

11503

8. Remove the two fuel pump retaining bolts.

9. Remove the fuel pump.
10. Remove the eight cylinder head cover bolts.
11. Remove cylinder head cover.

a - Cylinder head cover bolts (8)

b - Fuel pump retaining bolts (2)

b
a a

11485

Page 4B-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head
12. Remove the three cylinder head perimeter bolts located on the port side of the head.
13. Remove the eight cylinder head bolts.
14. Remove the cylinder head.

a - Perimeter bolts (3)

b - Head bolts (8)

a
b b

11491

Cylinder Head Disassembly

1. Loosen all of the adjuster locknuts and turn all of the adjusting screws out several turns.

b a - Locknut
b - Adjusting screw

11518

2. Remove the two rocker shaft retaining bolts.

3. Remove the oil galley cover bolt. Remove the oil galley cover.
NOTE: Note the position of the spacer at the bottom of the rocker shaft.

a - Spacer
b - Rocker shaft retaining bolts (2)
c - Oil galley cover bolt

a b c 11496

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-11

Cylinder Head
4. Thread a M10 ‑ 1.5 bolt into the bottom of the intake rocker shaft and remove the intake rocker shaft from the cylinder
head.

a - M10 ‑ 1.5 bolt

b - Intake rocker shaft

b
a
11486
5. Remove the bolt from the intake rocker shaft and repeat the procedure for the exhaust rocker shaft.
6. Remove the camshaft by sliding the camshaft toward the bottom of the head. Do not damage the camshaft bearing
surfaces.
7. Remove the upper camshaft seal.

a - Camshaft seal

a
11488

8. Compress the valve springs using a valve spring compressor.

11502

9. Remove the keepers, upper seats, springs, lower seats, and valves.

Valve Spring Compressor 91‑809494A1

NOTE: The valve seals are not reusable.

Page 4B-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head
10. Remove and discard all of the valve seals.

a - Valve seal
b - Valve guide
a

11521

Cleaning and Inspection

Valves
1. Inspect the valves for damage or warpage. Replace if necessary.
2. Measure the valve stem runout. Replace the valves if out of specification.

20970

Valve Stem Runout (Maximum)

Intake and exhaust 0.016 mm (0.0006 in.)
3. Measure the valve stem outer diameter. Replace valves if out of specification.

20971

Valve Stem Outside Diameter

Intake 5.46–5.48 mm (0.215–0.216 in.)
Exhaust 5.44–5.46 mm (0.214–0.215 in.)
4. Measure the margin thickness of the valve. Replace the valve if out of specification.

20972

Valve
Margin thickness 5.0 mm (0.197 in.) minimum

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-13

Cylinder Head

Valve Springs
1. Check the free length of each valve spring. Replace the valve springs if out of specification.

20973

Valve Spring
Free length 33.5–35 mm (1.32–1.38 in.)
2. Measure the valve spring tilt. Replace the valve springs if out of specification.
NOTE: Check each spring on a flat surface using a square. Rotate spring and check the space between the top coil and
the square.

20974

Valve Spring
Tilt limit 1.1 mm (0.043 in.) maximum

Cylinder Head Resurfacing

NOTE: The following procedure should only be attempted for minor scratches and minor warpage. Severe scratches or severe
warpage cannot be corrected with resurfacing the head.
1. Place a sheet of 400 ‑ 600 grit wet sandpaper on a flat surface.
2. Apply a light downward pressure on the head. Move the head in the pattern shown.
3. Rotate the head several times during the resurfacing procedure to avoid removing material from one side.
4. Thoroughly clean all sanding grit from the cylinder head.

3007

Page 4B-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Valve Guides
Measure the valve guide inner diameter. Replace the cylinder head if the valve guide inner diameter is out of specification.

a - Valve guide inside diameter

a
20975

Valve Guide Inside Diameter

Intake 5.51–5.55 mm (0.217–0.218 in.)
Exhaust 5.51–5.57 mm (0.217–0.219 in.)

Valve Seat Reconditioning

1. Clean the carbon deposits from the combustion chambers and valve seats. Check the valve seats for pitting.
2. Several different types of equipment are available for reseating valve seats. Follow the equipment manufacturers
instructions.
3. Apply a thin even layer of mechanic's bluing dye (Dykem) onto the valve seat.
4. Insert the valve into the valve guide and lap the valve slowly on the valve seat.
5. Remove the valve and measure the valve seat contact pattern width. Resurface the valve seat if not in specification.

a- Correct valve seat contact width

b- Valve seat too high
a b c d 20969 c- Valve seat too low
d- Valve seat too wide

Valve Seat Contact Width

Intake And Exhaust Valve 1.0–2.0 mm (0.0393–0.0787 in.)
6. To reface a valve seat, use a 30°, 45°, and 60° valve seat cutting tool.

a b a - 30° angle
c
b - 45° angle
c - 60° angle

20964

NOTE: When twisting the cutter, keep an even downward pressure to prevent chatter marks.
NOTE: After refacing the valve seat or replacing the valve and valve guide, the valve seat and valve face should be
lapped.
7. Start with the 45° cutting tool to clean up any pitting or rough surface of the valve seat.

45°
a - Rough surface of valve seat
a

20954

8. Use the 30° cutting tool to adjust the contact width of the top edge of the valve seat.

a - Previous contact width

a

30°
20976

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-15

Cylinder Head
9. Use the 60° cutting tool to adjust the contact width of the bottom edge of the valve seat.

a - Previous contact width

a

60°
20977

10. If the valve seat contact area is too wide and situated in the center of the valve face, use the 30° cutting tool to cut the top
edge of the valve seat and the 60° cutting tool to cut the bottom edge of the valve seat, to adjust its contact width.

o
30 a - Previous contact width

o
60 20979

11. If the valve seat contact area is too narrow and situated near the top of the valve face, use the 30° cutting tool to cut the
top edge of the valve seat. If necessary, use the 45° cutting tool to center the area of contact and set its width.

30° a - Previous contact width

a

20980
12. If the valve seat contact area is too narrow and situated near the bottom of the valve face, use the 60° cutting tool to cut
the bottom edge of the valve seat. If necessary, use the 45° cutting tool to center the area of contact and set its width.

a - Previous contact width

a

60°
20981

Cylinder Head Reassembly

Valve Installation
NOTE: Valve seals are color coded to ensure they are installed onto the proper valve guide. The black valve seal is for the
intake. The green valve seal is for the exhaust.

Page 4B-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head
1. Install new valve seals onto the valve guides.

a - Valve seal
b - Valve guide
a

11521

2. Lubricate the valve stem with 10W‑30 4‑Stroke Marine Engine Oil.
3. Install the valve, lower seat, spring, and upper seat.
4. Compress the valve spring using the valve spring compressor and install the keepers.

a - Valve spring compressor

b - Valve spring keepers

b b
11749

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Valve stem 92-8M0078625
Engine Oil

Cam and Rocker Installation

1. Install the upper camshaft seal. Lubricate the upper camshaft seal lip with 2‑4‑C with PTFE.

a - Camshaft seal

a
11488

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Camshaft seal lip 92-802859A 1

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-17

Cylinder Head
2. Inspect the camshaft bearing surfaces and rocker arm contact surface for damage. Ensure the compression release arms
move freely.

20949
b

a - Standard camshaft
b - Compression release arm

NOTE: Use caution when installing the camshaft to prevent damage to the cylinder head camshaft bearing surfaces.
3. Lubricate the camshaft and the cylinder head camshaft bearing surfaces with 10W‑30 4‑Stroke Marine Engine Oil. Install
the camshaft into the cylinder head.

a- Camshaft bearing surfaces

b- Cylinder head camshaft bearing surfaces
b c- Fuel pump lobe
a
d- Cam lobes
e- Camshaft seal area

a e
c d 11752

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Camshaft, cylinder head and camshaft bearing surface 92-8M0078625
Engine Oil
4. Lubricate the intake rocker shaft with 10W‑30 4‑Stroke Marine Engine Oil.
5. Install the intake rocker shaft, washers, springs, and rocker arms.
IMPORTANT: Install the washers with the rounded edge toward the rocker arm.

a - Washer
b - Rocker arm

a b
11492

Page 4B-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Intake rocker shaft 92-8M0078625
Engine Oil
6. Lubricate the exhaust rocker shaft with 10W‑30 4‑Stroke Marine Engine Oil.

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Exhaust rocker shaft 92-8M0078625
Engine Oil
7. Install the spacer, springs, washers, and rocker arms.
8. Install the rocker arm retaining bolts. Tighten the rocker arm retaining bolts to the specified torque.
9. Install the oil galley cover. Retain the oil galley cover with a bolt. Tighten the bolt to the specified torque.

a - Spacer
b - Rocker arm retaining bolts
c - Oil galley cover

a b c 11496

Description Nm lb. in. lb. ft.

Rocker arm retaining bolt (2) 9 80
Oil galley cover bolt 6 53
10. Install the oil pump. Refer to Section 4C ‑ Oil Pump.

Cylinder Head Installation

IMPORTANT: This engine utilizes an interference valve train design. Do not rotate the crankshaft or cams when the timing belt
is removed from the cam gears or crankshaft gear unless advised to do so. Failure to adhere to this caution may result in valve
and or piston damage.
1. Rotate the crankshaft so the number one piston (top piston) is at TDC.
2. Install the camshaft gear key onto the camshaft.
3. Install the camshaft gear onto the camshaft. Install the washer and bolt to retain the camshaft gear. Tighten the bolt to the
specified torque.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-19

Cylinder Head
4. Rotate the camshaft so the number one timing mark on the camshaft gear is aligned with the timing mark on the cylinder
head.

a b a - Cylinder head timing mark

b - Camshaft gear timing mark

20968

Description Nm lb. in. lb. ft.

Camshaft gear bolt 11 97

5. Ensure the cylinder head and cylinder block mating surface is clear of debris.
6. Install a new cylinder head gasket.
7. Install the cylinder head onto the cylinder block.
8. Apply a small amount of 10W‑30 4‑Stroke Marine Engine Oil to the cylinder head bolt threads. Tighten the cylinder head
bolts and the perimeter bolts in two steps in the sequence shown to the specified torque.

5 6

1 10
2

4 9
3

8 7 11

11790

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine
110 Cylinder head bolt threads 92-8M0078625
Engine Oil

Description Nm lb. in. lb. ft.

First Torque 10 88.5
Cylinder Head Bolts (M8 x 60) (8)
Final Torque 30 22
First Torque 6 53
Perimeter Bolts (M6 x 53) (3)
Final Torque 10 88.5
9. Install a new seal on the cylinder head cover.
10. Install the cylinder head cover onto the cylinder head. Secure the cylinder head cover with eight bolts. Tighten the cylinder
head cover bolts in two steps to the specified torque.

Page 4B-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cylinder Head
11. Install the fuel pump. Torque the fuel pump retaining screws to specification. Refer to Section 3C ‑ Service Procedures
for fuel pump hose connection.

a - Cylinder cover cover bolts (8)

b - Fuel pump retaining bolts (2)

b
a a

11485

Description Nm lb. in. lb. ft.

6 53
Cylinder head cover bolts (M6 x 53) (8)
9 80
Fuel pump retaining bolts 5.4 48
12. Install the oil pump. Refer to Section 4C ‑ Oil Pump.

Valve Adjustments
IMPORTANT: The timing belt and gears must be installed in the correct position or valve damage may occur.
1. Remove the flywheel cover and timing belt cover. Refer to Section 8A–Recoil Starter.
2. Disconnect the inlet and outlet fuel hoses on the fuel pump.
3. Remove the cylinder head cover.
4. Remove the spark plugs.
5. Measure the valve lash clearance with a feeler gauge. Adjust the valve lash if out of specification.
NOTE: When loosening locknuts, hold the adjusting screw with a square drive socket or crescent wrench to prevent it from
moving.

a a - Nut driver with square drive socket

b - Wrench

11809

Valve Clearance (Cold)

Intake 0.13–0.177 mm (0.005–0.007 in.)
Exhaust 0.177–0.228 mm (0.007–0.009 in.)
6. Perform the following adjustment steps if the valve lash is out of specification:
a. Turn the flywheel to align the camshaft gear timing mark with the timing mark on the cylinder block.
b. Adjust the intake and exhaust valve clearance for cylinder #1.
c. Turn the flywheel 240° and align the second mark (II) on the camshaft gear with the timing mark on the cylinder block.
d. Adjust the intake and exhaust valve clearance for cylinder #2.
e. Turn the flywheel 240° and align the third mark (III) on the camshaft gear with the timing mark on the cylinder block.
f. Adjust the intake and exhaust valve clearance for cylinder #3.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4B-21

Cylinder Head
g. Tighten the locknuts securely.

a - Timing mark on block

b - Timing marks on camshaft gear

a b
11804

IMPORTANT: When tightening locknuts, hold the adjusting screw with a square drive socket or crescent wrench to
prevent the adjusting screw from moving.

Description Nm lb. in. lb. ft.

Locknut 7 62
h. Install the spark plugs.
i. Install the cylinder head cover.
j. Install the flywheel cover and timing belt cover. Refer to Section 8A ‑ Recoil Starter.

Page 4B-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Oil Pump

Powerhead
Section 4C - Oil Pump
Table of Contents
Oil System Specifications ................................................. 4C-2 Oil Pump Inspection...........................................................4C-6
Oil Flow..............................................................................4C-4 Oil Pump Reassembly....................................................... 4C-6
Oil Pump Removal.............................................................4C-5 Oil Pump Installation..........................................................4C-8
Oil Pump Disassembly.......................................................4C-5

4
C

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4C-1

Oil Pump

Oil System Specifications

Oil System Specifications
Oil pump type Trochoid
Oil type
All temperatures FC‑W 10W30
Alternate viscosity above 4 °C (40 °F) FC‑W 25W40
Oil capacity 1.8 liter (1.9 U.S. qt)
Engine oil pressure at 75 °C (167 °F)
at 850 RPM 150 kPa (21 psi) or greater
at 5000 RPM 300 kPa (42 psi) or greater
Oil pump housing inside diameter (service limit) 40.8 mm (1.606 in.)
Outer rotor to oil pump housing inside diameter clearance (service limit) 0.25 mm (0.01 in.)
Outer rotor height (service limit) 14.96 mm (0.589 in.)
Rotor to oil pump cover clearance (service limit) 0.11 mm (0.0043 in.)
Inner rotor to outer rotor clearance (service limit) 0.16 mm (0.006 in.)

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Rotor cavity of oil pump, outer rotor, inner rotor
95 2-4-C with PTFE Oil pump driveshaft, oil pump cover seal 92-802859A 1
Oil pump base seal
10W-30 4-Stroke Marine Inlet and outlet of the oil pump, cylinder head oil pump bore,
110 92-8M0078625
Engine Oil camshaft

Page 4C-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Oil Pump

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4C-3

Oil Pump

Oil Flow

22572
1

3
m
k

o
1

3
l

h
g

i
j
e

f
d
1

4
1

3
c
b

3
a

Page 4C-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Oil Pump
a- Cylinder wall
b- Piston
c- Crank pin
d- Crankshaft bearing
e- Oil pressure switch
f- Main oil gallery
g- Oil filter
h- Oil regulator
i- Oil strainer
j- Oil sump
k- Camshaft journal
l- Cam bearings
m- Rocker shaft
n- Rocker arm
o- Oil pump

Oil Pump Removal

NOTE: Access to the oil pump requires the removal of the powerhead. Refer to Section 4A ‑ Powerhead Removal.
Remove the three oil pump retaining bolts. Remove the oil pump.

a - Oil pump retaining bolts (3)

11499

Oil Pump Disassembly

1. Remove the oil pump cover screws.

a - Oil pump cover screws (2)

11568

2. Remove the cover and discard the oil pump cover seal.
3. Push the oil pump shaft out of the oil pump body.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4C-5

Oil Pump
4. Remove the inner and outer rotors from the oil pump body.

e f g

d h
a b
c 11563

a- Oil pump seal (do not reuse)

b- Oil pump body
c- Outer rotor
d- Inner rotor
e- Oil pump shaft drive pin
f- Oil pump shaft
g- Oil pump cover seal (do not reuse)
h- Oil pump cover

Oil Pump Inspection

1. Inspect oil pump components for pitting and/or scratches. Replace if necessary.
2. Using a feeler gauge, measure the following oil pump clearances. Replace if worn or out of specification.
• Between the outer rotor and pump housing
• Between the inner rotor and outer rotor
• Between the outer rotor and oil pump cover
• Inside diameter of the oil pump housing
• Outer rotor height

a
a - Outer rotor and pump
d housing
b - Inner rotor and outer rotor
c - Outer rotor and oil pump
c cover
e d - Oil pump housing inside
diameter
e - Outer rotor height
b
17941

Oil Pump Clearance

Outer rotor and pump housing (maximum) "a" 0.25 mm (0.01 in.)
Inner rotor and outer rotor (maximum) "b" 0.16 mm (0.006 in.)
Outer rotor and oil pump cover (maximum) "c" 0.11 mm (0.004 in.)
Oil pump housing inside diameter (maximum) "d" 40.8 mm (1.606 in.)
Outer rotor height (minimum) "e" 14.96 mm (0.589 in.)

Oil Pump Reassembly

1. Lubricate the rotor cavity of the oil pump with 2‑4‑C with PTFE.
2. Lubricate the outer rotor with 2‑4‑C with PTFE. Install the outer rotor into the oil pump body.

Page 4C-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Oil Pump
3. Lubricate the inner rotor with 2‑4‑C with PTFE. Install the inner rotor into the oil pump body. Ensure the inner rotor drive pin
keyway faces towards the cover.

a - Drive pin
b - Oil pump shaft

b 11760

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Rotor cavity of oil pump, outer rotor, inner rotor 92-802859A 1
4. Lubricate the oil pump driveshaft with 2‑4‑C with PTFE. Install the oil pump driveshaft with the drive pin into the inner rotor.
Ensure the drive pin engages with the inner rotor keyway.
5. Lubricate the oil pump cover seal with 2‑4‑C with PTFE.

a- Inner rotor keyway

b- Oil pump shaft drive pin
d a c- Inner rotor
d- Oil pump cover seal

b 11761

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Oil pump driveshaft, oil pump cover seal 92-802859A 1
6. Install the oil pump cover seal.
7. Install the oil pump cover and secure with two screws. Tighten the screws to the specified torque.

a - Oil pump cover screw (2)

11568

Description Nm lb. in. lb. ft.

Oil pump cover screw (2) 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4C-7

Oil Pump

Oil Pump Installation

1. Lubricate the new oil pump base seal with 2‑4‑C with PTFE, and install the seal onto the oil pump.

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Oil pump base seal 92-802859A 1
2. Pour 15 drops of 10W‑30 4‑Stroke Marine Engine Oil into the inlet and outlet of the oil pump.
3. Lubricate the cylinder head oil pump bore and the camshaft with 10W‑30 4‑Stroke Marine Engine Oil.
4. Ensure the oil pump keyway and the camshaft drive slot are in alignment when assembling the oil pump to the cylinder
head.

11581

a - Oil pump inlet and outlet

b - Oil pump shaft keyway

Tube Ref No. Description Where Used Part No.

10W-30 4-Stroke Marine Inlet and outlet of the oil pump, cylinder head oil pump bore,
110 92-8M0078625
Engine Oil camshaft
5. Secure the oil pump to the cylinder head with three bolts. Tighten the bolts to the specified torque.

a - Oil pump bolt (3)

11499

Description Nm lb. in. lb. ft.

Oil pump bolt (3) 6 53

Page 4C-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cooling System

Powerhead
Section 4D - Cooling System
Table of Contents
Cooling System Specifications.......................................... 4D-2 Thermostat.........................................................................4D-3
Cooling System Description...............................................4D-2 Thermostat Measurement Test.................................. 4D-3
Water Flow Diagram.......................................................... 4D-3

4
D

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4D-1

Cooling System

Cooling System Specifications

Cooling System Specifications
Cooling system Water cooled ‑ thermostat control
Thermostat
Start to open temperature 60° ± 1.5 °C (140° ± 3 °F)
Full open temperature 75° ± 1.5 °C (167° ± 3 °F)
Valve lift 3 mm (0.12 in.)

Cooling System Description

Cooling water enters the cooling system through the lower unit water inlets. The water pump driven by the driveshaft, forces
water through the water tube into the exhaust adaptor plate and filling the powerhead. Immediately after the powerhead is filled
with water, a small steady stream of water exits the water pump indicator.
Water flow through the block is controlled by the thermostat. As the water temperature rises, the thermostat will begin to open
and allow water to pass by the thermostat, into the engine cooling jacket. The water then passes into the exhaust chamber area
of the driveshaft housing, cooling the exhaust gasses and on through the exhaust outlet of the propeller.
To allow complete passage filling and to prevent steam pockets, all cooling passages are interconnected. Small passages are
incorporated into the cooling system, to allow the cooling system to drain while the outboard is in a normal operating position.

Page 4D-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Cooling System

Water Flow Diagram

b c a- Fuel cooler
d b- Cylinder head
c- Thermostat
a
d- Cylinder block
e- Adapter plate
f- Water pump indicator
g- Idle relief
h- Water tube
i- Driveshaft housing
j- Water pump
k- Water inlet

e
f

k 22571

Thermostat
Inspect the thermostat. Replace if damaged, seized, or corroded.

Thermostat Measurement Test

1. Tie a piece of thread or other nonconductive material onto the thermostat.
2. Suspend the thermostat in cold water.
3. Suspend a thermometer in the water.
IMPORTANT: Do not allow the thermometer to contact the heating surface of the container. An inaccurate temperature
reading may result.
4. Slowly heat the water while observing the thermostat and thermometer.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 4D-3

Cooling System

5. Measure the thermostat opening when the specified water temperature is achieved.

3120

a - Minimum thermostat valve lift

Page 4D-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Mid-Section
Section 5A - Clamp/Swivel Bracket, Driveshaft Housing
Table of Contents
Driveshaft Housing Components....................................... 5A-4 Installation ‑ Power Trim and Gas Assist Models..... 5A-27
Swivel Bracket Components.............................................. 5A-6 Clamp Bracket/Swivel Bracket ‑ Power Trim and Gas
Clamp Bracket Components ‑ Power Trim and Gas Assist Assist Models............................................................... 5A-28
..................................................................................... 5A-10 Clamp Brackets ‑ Removal and Installation..............5A-28
Clamp Bracket Components ‑ Manual Tilt....................... 5A-12 Swivel Bracket/Clamp Bracket Removal.................. 5A-34
Driveshaft Housing Cover................................................ 5A-16 Swivel Bracket ‑ Disassembly and Reassembly.......5A-36
Removal....................................................................5A-16 Swivel Bracket/Clamp Bracket Installation............... 5A-40
Installation.................................................................5A-16 Clamp Bracket/Swivel Bracket ‑ Manual Tilt Models....... 5A-41
Exhaust Covers................................................................5A-16 Clamp Bracket Removal........................................... 5A-41
Port Cover Removal................................................. 5A-16
Port Cover Installation.............................................. 5A-16
Reverse Lock Hook.................................................. 5A-42
Reverse Lock Lever..................................................5A-45 5
A
Rear Cover Removal................................................ 5A-17 Tilt Stop Bracket....................................................... 5A-45
Rear Cover Installation............................................. 5A-18 Clamp Bracket Installation........................................ 5A-47
Lower Motor Mount Replacement....................................5A-19 Swivel Bracket/Clamp Bracket Removal.................. 5A-49
Removal....................................................................5A-19 Swivel Bracket ‑ Disassembly and Reassembly.......5A-50
Installation.................................................................5A-19 Swivel Bracket/Clamp Bracket Installation............... 5A-53
Upper Motor Mount Replacement....................................5A-21 Gearcase/Reverse Hook Operation.................................5A-54
Removal ‑ Power Trim Models................................. 5A-21 Operation.................................................................. 5A-54
Removal ‑ All Models................................................5A-21 Adjustments.............................................................. 5A-55
Installation ‑ All Models.............................................5A-24

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-1

Clamp/Swivel Bracket, Driveshaft Housing

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Grease fittings and co-pilot handle bolt
95 2-4-C with PTFE Tilt stop bracket pivot guide 92-802859A 1
Swivel bracket and steering shaft

Special Tools
Torch Lamp 91‑63209

Heats surfaces to aid in the removal and installation of interference fit engine
components.

8776

Page 5A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-3

Clamp/Swivel Bracket, Driveshaft Housing

Driveshaft Housing Components

2
29
3
11 28
11

27
26

25
16 17 18
20
15 21
22
24
11
23
15 11
10

19

9
3 4 8

3
7
6 2
5
1

14
12
13

16666

Page 5A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Driveshaft Housing Components

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Driveshaft housing
2 3 Bolt (M8) 15 132.7
3 9 Washer
4 1 Plug
5 1 Drain plug 23.7 17.5
6 1 Washer
7 6 Bolt (M8) 30 22
8 1 Gasket
9 1 Drain cover
10 8 Bolt 6 53
11 4 Dowel pin
12 1 Skirt
13 2 Tapping screw Drive tight
14 2 Washer
15 2 Skirt seal
16 1 Skirt seal
17 1 Grommet
18 1 Idle exhaust cover
19 6 Bolt 6 53
20 1 Idle exhaust cover gasket
21 1 Plate
22 1 Gasket
23 1 Grommet
24 1 Plate
25 1 Gasket
26 1 Rubber seal
27 1 Adapter plate
28 1 Oil seal
29 1 Gasket

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-5

Clamp/Swivel Bracket, Driveshaft Housing

Swivel Bracket Components

44

43
42
41
40

39
38

35
31
36
34 37
28 30
29
33
26
32
25 3
24
2
23
23
27
22 1

18
95 21 20

19

15
2 14
12 13
4 11
3
10
7
6

8 10
16 17
5
9 16672

Page 5A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Swivel Bracket Components

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Swivel bracket
2 2 Bushing
3 2 Thrust plate
4 1 O‑ring
5 1 O‑ring
6 1 Bottom yoke
7 1 Ground wire
8 1 Bolt 6 53
9 2 Bolt (Lower) 40 29.5
10 4 Washer
11 1 Rubber damper (lower)
12 2 Lower mount
13 2 Washer
14 21 Washer
15 2 Nut
16 2 Cover (lower)
17 4 Bolt (M6 x 20) 6 53
18 1 Decal ‑ Secure Engine Warning
19 1 Ground wire
20 1 Washer
21 3 Grease fitting
22 1 Bolt (handle)
23 2 Disk (handle)
24 1 Washer (handle)
25 1 Washer (handle)
26 1 Co‑pilot handle (handle)
27 1 Grip (handle)
28 1 Button (handle)
29 1 Washer (handle)
30 1 Nut
31 1 Co‑pilot plate (handle)
32 1 Screw (M6 x 16) (handle) 6 53
33 2 Collar (handle)
34 1 Steering shaft assembly
35 2 Washer
36 2 Lock plate
37 2 Nut 20.3 179.7
38 2 Mount retainer
39 4 Bolt 6 53
40 2 Rubber mount (upper)
41 2 Upper lock retainer
42 2 Rubber damper (upper)
43 2 Screw (upper) 20.3 179.7
44 2 Upper damper

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-7

Clamp/Swivel Bracket, Driveshaft Housing

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Grease fittings and co-pilot handle bolt 92-802859A 1

Page 5A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Swivel Bracket Components

44

43
42
41
40

39
38

35
31
36
34 37
28 30
29
33
26
32
25 3
24
2
23
23
27
22 1

18
95 21 20

19

15
2 14
12 13
4 11
3
10
7
6

8 10
16 17
5
9 16672

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-9

Clamp/Swivel Bracket, Driveshaft Housing

Clamp Bracket Components ‑ Power Trim and Gas Assist

3
1 8

9
6
7
9
23 30 10
22
21 4 12
30
27
32 11
33 15 12
31
16
13
2
36 5
35 14
35 18
17 19
26 28
29 21
22
23
21 21 37 20
8 24
34
9 25

40
41
39
42
43
43
44
38

21 21
45 21

16673

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 Clamp/Swivel Bracket, Driveshaft Housing

Clamp Bracket Components - Power Trim and Gas Assist

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Starboard clamp bracket
2 1 Port clamp bracket
3 1 Tilt tube and two nuts 24 17.7
4 2 Bushing
5 1 Thrust rod
6 1 Cotter pin
7 1 Swivel bracket
8 2 Ground wire
9 3 Bolt 6 53
10 1 Clamp
11 1 Clamp
12 2 Screw
13 2 Clamp screw
14 2 Pad
15 4 Washer
16 4 Nut 68 50
17 4 Bolt
18 4 Washer
19 1 Decal ‑ Secure Engine Warning
20 1 Pin
21 5 or 6 Bushing
22 2 Washer
23 2 C‑ring
24 1 Anode
25 2 Bolt 6 53
26 1 Tilt stop
27 1 Pin
28 1 Grip
29 1 Spring
30 2 Collar
31 2 Upper cylinder spring
32 1 Bolt
33 1 Washer
34 1 Power trim/tilt assembly
35 2 Bushing
36 1 Bushing
37 1 Cable tie (8 in.)
38 1 Shock absorber (Gas)
39 1 Lever
40 1 Grip
41 1 Button
42 1 Bolt
43 2 Washer
44 1 Nut 6 53
45 1 Collar

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-11

Clamp/Swivel Bracket, Driveshaft Housing

Clamp Bracket Components ‑ Manual Tilt

41

42

40
43
44 45
30
46
4

3
1 47
15
16

12 13
5 16 20 17
14 18
18
19
20
21 19
11 10 9
9
5
8 22
6
23
24
9
25
7
27 2 4
26 9 10

36 37
21

39
38 29
28

32
34 35 31
33

22848

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 Clamp/Swivel Bracket, Driveshaft Housing

Clamp Bracket Components - Manual Tilt

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Starboard clamp bracket
2 1 Port clamp bracket
3 1 Tilt tube and nut
4 2 Cap nut
5 2 Bushing
6 2 Pad
7 1 Nut 24 17.7
8 1 Stud
9 4 Washer
10 2 Nut 6 53
11 2 Clamp screw
12 1 Thrust rod
13 1 Spring
14 1 Decal ‑ Co‑pilot (handle)
15 1 Ground wire (to swivel bracket)
16 2 Bolt 6 53
17 1 Port tilt stop
18 2 Bolt 11 97.3
19 2 Wave washer
20 2 Washer (to swivel bracket)
21 4 Washer
22 2 Nut 68 50
23 2 Spring
24 1 Anode
25 1 Bolt 6 53
26 2 Bolt
27 1 Reverse lock
28 2 Bolt
29 2 Washer
30 1 Cotter pin
31 1 Link bushing
32 1 Link
33 1 Tilt stop bracket
34 2 Bolt 27 20
35 1 Plate
36 1 Pin
37 1 Bracket
38 1 Stop
39 1 Friction spring
40 1 Reverse lock lever
41 1 Reverse lock lever grip
42 1 Button
43 1 Bolt 11 97.3
44 2 Wave washer
45 1 Washer
46 1 Spring

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Clamp/Swivel Bracket, Driveshaft Housing

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
47 1 Pin

Page 5A-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

Clamp Bracket Components - Manual Tilt

41

42

40
43
44 45
30
46
4

3
1 47
15
16

12 13
5 16 20 17
14 18
18
19
20
21 19
11 10 9
9
5
8 22
6
23
24
9
25
7
27 2 4
26 9 10

36 37
21

39
38 29
28

32
34 35 31
33

22848

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-15

Clamp/Swivel Bracket, Driveshaft Housing

Driveshaft Housing Cover

Removal
1. Remove the two screws securing the driveshaft housing cover.
2. Remove the cover by spreading and pulling cover over the driveshaft housing.

a - Driveshaft housing cover screw

b - Oil drain plug
c - Exhaust relief tube

c a

9394

Installation
1. Install the driveshaft housing cover. Align the cover with the bottom cowl. Ensure that the exhaust relief tube and oil drain
plug are aligned with the holes in the driveshaft cover.
2. Attach the cover with two screws. Drive tight.

Exhaust Covers
Port Cover Removal
1. Remove the eight bolts securing the port exhaust cover.
2. Remove the gasket.

a - Port exhaust cover

b - Port exhaust cover bolts (8)

b
b

a
9395

Port Cover Installation

1. Clean the gasket surfaces on the driveshaft housing and port exhaust cover before installing a new gasket.
2. Install a new gasket.

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 Clamp/Swivel Bracket, Driveshaft Housing

3. Install the port exhaust cover with eight bolts.

c
a c

b
9990

a - Gasket surface
b - Port exhaust cover
c - Cover bolts

4. Tighten the bolts in sequence to the specified torque.

6 5
2
1
3
4
7
8

9991

Description Nm lb. in. lb. ft.

Port exhaust cover bolt (8) 6 53

Rear Cover Removal

1. Remove the six bolts securing the exhaust cover.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-17

Clamp/Swivel Bracket, Driveshaft Housing

2. Remove the rear exhaust cover and gasket.

a - Rear exhaust cover

a b - Rear exhaust cover bolts (6)

b b

10009

Rear Cover Installation

1. Clean the gasket surfaces on the driveshaft housing and rear exhaust cover before installing a new gasket.
2. Install a new gasket.
3. Install the rear exhaust cover and secure with six bolts.

a - Rear exhaust cover gasket surface

b b - Rear exhaust cover
c - Cover bolts (6)

a
c c

10010

4. Tighten the bolts in sequence to specified torque.

5 6

1 2

4 3

10011

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 Clamp/Swivel Bracket, Driveshaft Housing

Description Nm lb. in. lb. ft.

Rear exhaust cover bolts (6) 6 53

Lower Motor Mount Replacement

Removal
NOTE: Change one motor mount at a time.
1. Remove the two bolts securing the lower motor mount cover to the driveshaft housing.
2. Remove the two ground cables from the bolt.

a - Lower motor mount cover bolts

b - Lower motor mount cover
c - Ground cable (2)
b
a

10035

3. Remove the locknut from the motor mount bolt.

4. Remove the bolt from the swivel yoke.
5. Pry the motor mount from the driveshaft housing.

e d b a- Lower motor mount bolt

c b- Washer
f c- Swivel yoke
b d- Lower motor mount
g e- Rubber washer
f- Washer
a g- Locknut

10036

Installation
1. Install the new lower motor mounts into the driveshaft housing.
2. Install a bolt through the swivel yoke.
3. Install a washer on the bolt and push the bolt through the lower motor mount.
4. Install a new rubber washer over the lower motor mount.

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Clamp/Swivel Bracket, Driveshaft Housing

5. Install a washer and locknut. Tighten each locknut to specified torque.

e d b a- Lower motor mount bolt

c b- Washer
f c- Swivel yoke
b d- Lower motor mount
g e- Rubber washer
f- Washer
a g- Locknut

10036

Description Nm lb. in. lb. ft.

Lower motor mount bolt/nut 40 29.5
6. Install the lower motor mount cover with two bolts.
7. Attach the two ground cables to the starboard lower motor mount bolt.
8. Tighten the cover bolts to specified torque.

a - Cover screws
b - Lower motor mount cover
c - Ground cable (2)
b
a

10035

Description Nm lb. in. lb. ft.

Lower motor mount cover bolt 6 53

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 Clamp/Swivel Bracket, Driveshaft Housing

Upper Motor Mount Replacement

Removal ‑ Power Trim Models
1. Remove the electrical plate cover and disconnect the power trim wires from the solenoids.

a b a - Green heavy gauge pump wire/green

relay terminal (down)
b - Blue heavy gauge pump wire/blue relay
terminal (up)

20926

2. Remove the two harness clamps securing the power trim wire harness to the clamp bracket and pull the wire harness
through the clamp bracket.

b c a- Port clamp bracket

b- Tilt tube port side nut
c- Power trim harness
d- Harness clamps (2)
d e- Tilt pin and cotter pin
f- Lower pivot pin, bushing, washer, and snap ring

f
19142

Removal ‑ All Models

1. Remove the driveshaft housing cover. Refer to Driveshaft Housing Cover, preceding.
2. Remove the lower cowl cover. Refer to Section 7B.
3. On tiller handle models, remove the throttle only assembly. Refer to Section 7A.
4. Remove the upper shift shaft from the horizontal shift lever shaft. Refer to Section 7A.
5. Remove the flywheel cover and flywheel. Refer to Section 2A.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-21

Clamp/Swivel Bracket, Driveshaft Housing

6. Remove the roll pin securing the upper shift shaft to the coupler.

a - Upper shift shaft

b - Coupler
c - Roll pin

a
c
b

10071

7. On manual tilt models:

a. Pry the bushing open and remove the reverse lock link from the bushing and reverse lock hook.
b. Remove the reverse lock link from the upper shift shaft.

b b

d
c
20928

a- Bushing
b- Reverse lock link
c- Reverse lock hook
d- Upper shift shaft

8. Push the upper shift shaft up through the powerhead assembly until it clears the swivel bracket. Do not pull the upper shift
shaft through the grommet.

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 Clamp/Swivel Bracket, Driveshaft Housing

NOTE: Clamp a Vice‑Grip ® pliers to the upper shift shaft to hold it in this position.

a a - Upper shift shaft

b - Grommet

18791

9. Remove the two lower motor mounts. Refer to Lower Motor Mount Replacement, preceding.
10. Bend the tab on the locking plates.
11. Remove the nuts securing the upper motor mounts.

a- Washer
a
b- Locking plate
c- Nut
d- Bolt
d

18793

12. While holding the upper shift shaft, remove the swivel bracket/clamp bracket/steering arm assembly from the driveshaft
housing and adapter plate.

b a- Driveshaft housing
b- Steering arm
c- Clamp bracket assembly
d- Swivel bracket

c
a
d
18821

13. Remove the two bolts and the mount retainer securing each upper motor mount.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-23

Clamp/Swivel Bracket, Driveshaft Housing

14. Remove both upper motor mounts from the adapter plate.

b
c

18801

a - Mount retainer
b - Bolt
c - Upper motor mount

15. Remove the upper damper from each upper motor mount cavity.

Installation ‑ All Models

1. Inspect each upper motor mount cavity for corrosion or debris. Ensure that the bore is clean before installing new motor
mounts.
2. Install an upper damper in each upper motor mount cavity.

18828

a - Adapter plate
b - Upper motor mount cavity
c - Upper damper

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 Clamp/Swivel Bracket, Driveshaft Housing

3. Assemble the remaining upper motor mount components as shown and install in the adapter plate.

f a- Upper damper
b- Bolt
c- Damper
d- Upper lock retainer
g e- Upper motor mount
f- Notch for retainer
a g- Flat side on bolt
b
c
d
e 18820

4. Align each upper motor mount so the notch and the flat side of the bolt are towards the outside of the engine.
5. Secure each upper motor mount in the adapter plate with a mount retainer and two bolts. Tighten the bolts to the specified
torque.

b
c

18801

a - Mount retainer
b - Bolt
c - Upper motor mount

Description Nm lb. in. lb. ft.

Upper motor mount retaining bolts 6 53
6. Push the upper shift shaft up through the powerhead assembly until it clears the swivel bracket.

a a - Upper shift shaft

20966

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Clamp/Swivel Bracket, Driveshaft Housing

7. Install the swivel bracket/clamp bracket/steering arm assembly onto the upper motor mount bolts.

b a- Driveshaft housing
b- Steering arm
c- Clamp bracket assembly
d- Swivel bracket

c
a
d
18821

8. Install a washer, locking plate, and nut on each upper motor mount bolt. Torque the nut to specified torque.

Description Nm lb. in. lb. ft.

Upper motor mount nut 20.3 179.7
9. Bend each locking plate tab against the nut to prevent the nut from loosening.

a- Washer
a
b- Locking plate
c- Nut
d- Upper motor mount bolt
d

18793

10. Install the lower motor mounts. Refer to Lower Motor Mount Replacement, preceding.
11. On manual tilt models:
a. Assemble the reverse lock link to the upper shift shaft.
b. Install the reverse lock link into the bushing and reverse lock hook.

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 Clamp/Swivel Bracket, Driveshaft Housing

c. Close the bushing.

b b

d
c
20928

a- Bushing
b- Reverse lock link
c- Reverse lock hook
d- Upper shift shaft

12. Install the shift shaft coupler as follows:

a. Shift the gearcase into forward.
b. Shift the gearcase into neutral.
c. Shift the tiller handle or remote control to neutral.
d. Align the roll pin hole in the adjustable coupler to align with the hole in the upper shift shaft.
e. Install the upper shift shaft into the coupler.
f. Shift the outboard's control to forward ‑ neutral ‑ reverse ‑ neutral.
g. If the operation is smooth, install the roll pin through the coupler and upper shift shaft.

a - Upper shift shaft

b - Coupler
c - Lower shift shaft (gearcase)

a
b
c

20922

13. Install the flywheel and flywheel cover. Refer to Section 2A.
14. Install the upper shift shaft to the horizontal shift lever shaft. Refer to Section 7A.
15. Install the throttle only assembly (tiller handle models). Refer to Section 7A.
16. Install the lower cowl cover. Refer to Section 7B.
17. Install the driveshaft housing cover. Refer to Driveshaft Housing Cover, preceding.

Installation ‑ Power Trim and Gas Assist Models

1. Route the power trim harness through the clamp.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-27

Clamp/Swivel Bracket, Driveshaft Housing

2. Attach the power trim harness clamps to the harness and attach to the clamp bracket.

b c a- Port clamp bracket

b- Tilt tube port side nut
c- Power trim harness
d- Harness clamps (2)
d e- Tilt pin and cotter pin
f- Lower pivot pin, bushing, washer, and snap ring

f
19142

3. Connect the blue and green wires to the solenoids.

a b a - Green heavy gauge pump wire/green

relay terminal (down)
b - Blue heavy gauge pump wire/blue relay
terminal (up)

20926

4. Attach the electrical plate cover with two bolts. Tighten the bolts to specified torque.

Description Nm lb. in. lb. ft.

Electrical plate cover bolts 6 53

Clamp Bracket/Swivel Bracket ‑ Power Trim and Gas Assist Models

Clamp Brackets ‑ Removal and Installation
Port Clamp Bracket Removal
1. Remove the two bolts securing the anode to the clamp brackets.

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 Clamp/Swivel Bracket, Driveshaft Housing

2. Remove the transom bolts from the port clamp bracket.

g e g f g a- Bolt and ground cable

b- Anode
c- Bolt
d- Port clamp bracket
b e- Lower pivot pin
d f- Starboard clamp bracket
g- Bushing

a c

19141

3. Remove the electrical plate cover and disconnect the power trim wires from the solenoids.

a b a - Green heavy gauge pump wire/green

relay terminal (down)
b - Blue heavy gauge pump wire/blue relay
terminal (up)

20926

4. Remove the two harness clamps securing the power trim wire harness to the clamp bracket and pull the wire harness
through the clamp bracket.
5. Remove the tilt tube nut from the port side.
6. Remove the snap ring and washer from the port end of the lower pivot pin.
7. Push the lower pivot pin through the port clamp bracket.

b c a- Port clamp bracket

b- Tilt tube nut
c- Power trim harness
d- Harness clamps (2)
d e- Tilt pin and cotter pin
f- Lower pivot pin, bushing, washer, and snap ring

f
19142

8. Remove the port clamp bracket.

9. Inspect the bushings and washers. Replace if required.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-29

Clamp/Swivel Bracket, Driveshaft Housing

Port Clamp Bracket Installation

1. Install a washer on the tilt tube.
2. Install a bushing in the power trim unit.
3. Ensure that the tilt lock lever is positioned as shown.

a- Tilt tube
a
b- Washer
c- Power trim unit
d- Bushing
b
e- Lower pivot pin
f f- Tilt lock lever

d
e
19176

4. Install the clamp bracket on the tilt tube.

5. Route the power trim harness through the clamp.
6. Attach the power trim harness clamps to the harness and attach to the clamp bracket.
7. Install the nut on the tilt tube.
8. Align the lower pivot pin with the clamp bracket and push the pin through the clamp bracket.
9. Install the bushing, steel washer, and snap ring on the lower pivot pin.
10. Tighten the tilt tube nut to specified torque.

b c a- Port clamp bracket

b- Tilt tube nut
c- Power trim harness
d- Harness clamps (2)
d e- Tilt pin with cotter pin
f- Lower pivot pin, bushing, washer, and snap ring

f
19142

Description Nm lb. in. lb. ft.

Tilt tube nut 24 17.7
Power trim harness clamp bolt 6 53
11. Route the power trim harness through the bottom cowl.

Page 5A-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

12. Connect the blue and green power trim wires to the solenoids.

a b a - Green heavy gauge pump wire/green

relay terminal (down)
b - Blue heavy gauge pump wire/blue relay
terminal (up)

20926

13. Attach the electrical plate cover with two bolts. Tighten the bolts to specified torque.

Description Nm lb. in. lb. ft.

Electrical plate cover bolts 6 53
14. Attach the ground cable to the anode and attach the anode to the clamp brackets with two bolts. Tighten the bolts to
specified torque.

Description Nm lb. in. lb. ft.

Anode bolts 6 53
15. Reinstall the transom bolts through the port clamp bracket.

g e g f g a- Bolt and ground cable

b- Anode
c- Bolt
d- Port clamp bracket
b e- Lower pivot pin
d f- Starboard clamp bracket
g- Bushing

a c

19141

Starboard Clamp Bracket Removal

1. Remove the two bolts securing the anode to the clamp brackets.
2. Remove the transom bolts from the starboard clamp bracket.

g e g f g a- Bolt and ground cable

b- Anode
c- Bolt
d- Port clamp bracket
b e- Lower pivot pin
d f- Starboard clamp bracket
g- Bushing

a c

19141

3. Loosen the tilt tube nut from the port side.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-31

Clamp/Swivel Bracket, Driveshaft Housing

4. Push the tilt tube towards the starboard side.

b
19223

a - Tilt tube
b - Starboard tilt tube nut
c - Port tilt tube nut

5. Remove the tilt tube nut from the starboard side.

6. Remove the snap ring and washer from the starboard end of the lower pivot pin.

a
a- Starboard tilt tube nut
b- Starboard clamp bracket
c- Lower pivot pin, bushing, washer, and snap ring
d- Tilt pin
e- Tilt lock lever
e b

d
c 19220

7. Move the starboard clamp bracket away from the swivel bracket.
8. Remove the ground cable from the swivel bracket.

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 Clamp/Swivel Bracket, Driveshaft Housing

9. Remove the clamp bracket from the tilt tube.

a- Ground cable and bolt

b- Washer
c- Tilt tube
d- Starboard clamp bracket
a
b
c

19217

Starboard Clamp Bracket Installation

1. Install a bushing in the starboard clamp bracket.
2. Attach the ground cable with a bolt to the clamp bracket. Tighten the bolt to specified torque.

a - Bushing
b - Starboard clamp bracket
a b c - Ground cable and bolt

19225

Description Nm lb. in. lb. ft.

Ground cable bolt 6 53
3. Install a washer on the tilt tube.
4. Install the clamp bracket assembly on the tilt tube.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-33

Clamp/Swivel Bracket, Driveshaft Housing

5. Attach the ground cable with a bolt to the swivel bracket. Tighten the bolt to specified torque.

a- Ground cable and bolt

b- Washer
c- Tilt tube
d- Starboard clamp bracket
a
b
c

19217

Description Nm lb. in. lb. ft.

Ground cable bolt 6 53
6. Ensure that the tilt lock lever is positioned as shown.
7. Align the lower pivot pin and power trim unit with the starboard clamp bracket bore.
8. Push the clamp bracket towards the swivel bracket while inserting the lower pivot pin through the starboard clamp bracket.
9. Fully thread the starboard tilt tube nut on the tilt tube.
10. Push the tilt tube to the port side until it seats in the hex cavity in the clamp bracket.
11. Tighten the port tilt tube nut to specified torque.
12. Install a bushing, washer, and snap ring on the lower pivot pin.

a
a- Starboard tilt tube nut
b- Starboard clamp bracket
c- Lower pivot pin, bushing, washer, and snap ring
d- Tilt pin
e- Tilt lock lever
e b

d
c 19220

Description Nm lb. in. lb. ft.

Port tilt tube nut 24 17.7
13. Reinstall the transom bolts through the starboard clamp bracket.

Swivel Bracket/Clamp Bracket Removal

Power Trim Models
1. Remove the electrical plate cover and disconnect the power trim wires from the solenoids.
2. Pull the wire harness through the bottom cowl.

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 Clamp/Swivel Bracket, Driveshaft Housing

Shift Control Removal - Remote Control Models

1. Remove the two bolts securing the bottom cowl cover and remove the cover.
2. Remove the bolt securing the remote control cable clamp bracket.
3. Remove the cotter pins and washers on the remote control throttle and shift cables.
4. Remove the cotter pins and washers on the shift rod.
5. Remove the shift rod, throttle cable, and shift cable.
6. Loosen the bolts securing the remote control bracket approximately 6 mm (1/4 in.).
7. Slide the shift lever shaft out from the shift lever shaft bracket and remove the upper shift shaft. Refer to Section 7A ‑
Remote Control Models ‑ Shift Control Removal.

Shift Control Removal - Tiller Handle Models

1. Remove the bottom cowl upper clamp. Remove the shift/throttle cables and the throttle link. Refer to Section 7B ‑ Tiller
Handle Removal.
2. Remove the two throttle rods from the throttle lever. Refer to Section 7B ‑ Tiller Handle Removal.
3. Remove the throttle only button retainer clip from the cowl.
4. Remove the retainer, grommet and throttle only button.
5. Remove the three screws securing throttle only assembly to the engine block.
6. Remove the upper shift shaft from the shift lever. Refer to Section 7A ‑ Throttle Only Removal.

Removal
1. Remove the flywheel cover and flywheel. Refer to Section 2A ‑ Flywheel Removal.
2. Attach a chain hoist hook to the powerhead lift eye.
3. Support the outboard with the chain hoist.

19355

4. Remove the two bolts securing each lower motor mount cover to the driveshaft housing.
5. Remove the locknuts from the motor mount bolts.
6. Remove the bolts from the swivel bracket yoke. Refer to Lower Motor Mount Replacement, preceding.
7. Remove the roll pin securing the upper shift shaft to the coupler.
8. Straighten the tab on the lock plate for each upper motor mount.
9. Remove the nut securing each upper motor mount.
10. Push the upper shift shaft up through the powerhead assembly until it clears the swivel bracket. Do not pull the upper shift
shaft through the grommet.
NOTE: The upper shift shaft may be held in this position by clamping a Vice Grip® pliers to it.
11. While holding the upper shift shaft, remove the swivel/clamp brackets from the driveshaft housing and adapter plate. Refer
to Upper Motor Mount Replacement, preceding.

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Clamp/Swivel Bracket, Driveshaft Housing

Swivel Bracket ‑ Disassembly and Reassembly

Disassembly
1. Extend the power trim cylinder to the tilt position.
2. Engage the tilt lock lever.
3. Remove the rubber damper from the bottom yoke.
4. Remove the ground cable bolt from the bottom yoke.
5. Remove the snap ring from the steering shaft assembly.

a a- Rubber damper
b- Bottom yoke
c- Ground cable bolt
d- Steering shaft assembly
e- Snap ring

e b

d
19373

6. Use a torch lamp to warm the bottom yoke.

7. Use a dead blow hammer to remove the bottom yoke from the steering shaft assembly.

a - Torch lamp
a b - Dead blow hammer
b
c - Bottom yoke

19379

Torch Lamp 91‑63209

8. Wait until the steering shaft is cool.
9. Remove the washer, O‑ring, and bushing from the steering shaft.

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 Clamp/Swivel Bracket, Driveshaft Housing

10. Remove the steering shaft from the swivel bracket.

a- Steering shaft
a b- Swivel bracket
c- Bushing
b d- O‑ring
e- Washer

c
e d 19381

11. Remove the port clamp bracket to remove the swivel bracket.
a. Remove the tilt tube nut.
b. Remove the two power trim harness clamps.
c. Pull the harness through the hole in the clamp bracket.
d. Remove the snap ring and washer from the lower pivot pin.
e. Loosen the port clamp bracket clamp screw and remove the transom bolts from the port clamp bracket.
f. Remove the port clamp bracket.
g. Remove the swivel bracket.

a- Tilt tube
a
d b- Nut
c- Power trim harness clamps
d- Power trim harness
c e- Port clamp bracket
b
f- Transom bolt (2 per clamp bracket)
g- Lower pivot pin washer and snap ring

f
g
19391

Reassembly
1. Install the swivel bracket:
a. Install the swivel bracket to the tilt tube and starboard clamp bracket.
IMPORTANT: The tilt tube end with the fewer threads is assembled to the starboard side clamp bracket.
b. Attach the port clamp bracket.
c. Tighten the port clamp bracket clamp screw and install the transom bolts through the port clamp bracket.
d. Push the lower pivot pin through both clamp brackets.
e. Install the snap ring and washer from the lower pivot pin.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-37

Clamp/Swivel Bracket, Driveshaft Housing

f. Pull the harness through the hole in the clamp bracket.

g. Attach the two power trim harness clamps.
h. Install the tilt tube nut. Tighten the port side nut to the specified torque.

a- Tilt tube
a
d b- Nut
c- Power trim harness clamps
d- Power trim harness
c e- Port clamp bracket
b
f- Transom bolt (2 per clamp bracket)
g- Lower pivot pin washer and snap ring

f
g
19391

Description Nm lb. in. lb. ft.

Port tilt tube nut 24 17.7
Transom bolts 68 50
2. Install the thrust washer and bushing on the steering arm.
3. Install the steering shaft assembly in the swivel bracket.

a a- Steering shaft assembly

b
b- Thrust washer
c c- Bushing
d d- Swivel bracket

19014

4. Push the steering shaft assembly completely into the steering bracket.

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 Clamp/Swivel Bracket, Driveshaft Housing

5. Install a bushing, O‑ring, and thrust washer.

a- Steering arm
b- Bushing
a c- O‑ring
d- Thrust washer
e- Steering shaft assembly

b
c
d
e

19865

6. Align the bottom yoke on the steering shaft.

7. Warm the bottom yoke with the torch lamp.
8. Hold the steering shaft assembly.
9. Use a dead blow hammer to install the bottom yoke on the steering shaft assembly.

a- Steering shaft assembly

c b- Bottom yoke
c- Torch lamp
b d- Dead blow hammer
a

d 19869

Torch Lamp 91‑63209

10. Install the snap ring to the steering shaft assembly.
11. Install the ground cable to the bottom yoke.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-39

Clamp/Swivel Bracket, Driveshaft Housing

12. Install the rubber damper to the bottom yoke.

a a- Rubber damper
b- Bottom yoke
c- Ground cable bolt
d- Steering shaft
e- Snap ring

e b

d
19373

13. Disengage the tilt lock lever.

14. Return the power trim cylinder to the operating position.

Swivel Bracket/Clamp Bracket Installation

Installation
1. Attach a chain hoist hook to the powerhead lift eye.
2. While holding the upper shift shaft, install the swivel/clamp brackets to the driveshaft housing and adapter plate. Refer to
Upper Motor Mount Installation, preceding.
3. Push the upper shift shaft down through the powerhead assembly.
4. Install the nut securing each upper motor mount. Tighten upper motor mount nut to specified torque.

Description Nm lb. in. lb. ft.

Upper motor mount nut 20.3 179.7
5. Bend the lock plate tab against the nut to prevent the nut from loosening.
6. Install the roll pin securing the upper shift shaft to the coupler.
7. Install the bolts through the swivel bracket yoke. Refer to Lower Motor Mount Installation, preceding.
8. Install the locknut on the lower motor mount bolt.
9. Install the two bolts securing the lower motor mount cover to the driveshaft housing.
10. Remove the chain hoist from the powerhead lift eye.

19355

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 Clamp/Swivel Bracket, Driveshaft Housing

11. Install the flywheel and flywheel cover. Refer to Section 2A ‑ Flywheel Installation.

Shift Control Installation - Remote Control Models

1. Install the upper shift shaft to the shift lever.
2. Push the shift lever shaft into the shift lever shaft bracket.
3. Tighten the bolts securing the remote control bracket.

Description Nm lb. in. lb. ft.

Remote control bracket bolts 6 53
4. Install the shift rod, throttle cable, and shift cable.
5. Install the cotter pins and washers on the shift rod.
6. Install the cotter pins and washers on the remote control throttle and shift cables.
7. Install the bolt securing the remote control cable clamp bracket. Refer to Section 7A ‑ Remote Control Models ‑ Shift
Control Assembly and Installation.
8. Install the bottom cowl cover and secure with two bolts.

Power Trim Models

1. Pull the wire harness through the bottom cowl.
2. Connect the power trim wires to the solenoids and install the electrical plate cover.

Shift Control Installation - Tiller Handle Models

1. Install the upper shift shaft into the shift lever.
2. Install the throttle only assembly to the shift lever shaft.
3. Attach the throttle only assembly to the powerhead with three bolts. Tighten the bolts to specified torque.
4. Install the throttle only button, grommet, and retainer.
5. Install the throttle only retaining clip. Refer to Section 7A ‑ Throttle Only Reassembly and Installation.

Description Nm lb. in. lb. ft.

Throttle only attaching bolts (3) 6 53
6. Install the throttle link to the throttle lever. Refer to Section 7B ‑ Tiller Handle.
7. Install the throttle cables to the throttle only pulley. Refer to Section 7B ‑ Tiller Handle.
8. Install the grommet and bottom cowl upper clamp. Refer to Section 7B ‑ Tiller Handle.

Clamp Bracket/Swivel Bracket ‑ Manual Tilt Models

Clamp Bracket Removal
NOTE: If only one clamp bracket is being removed, the outboard may remain on the transom.
1. Loosen the clamp screws.
2. Remove the outboard from the transom.
3. Remove the tilt stop pin and clamp bracket stud.
4. Remove the starboard side tilt tube locknut.

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Clamp/Swivel Bracket, Driveshaft Housing
5. Remove the starboard clamp bracket from the tilt tube.

a a - Tilt tube locknut

b - Clamp bracket stud
c - Tilt stop pin

b
c 20851

6. Remove the bolt securing the port tilt stop. The assembly includes a flat washer between the tilt stop and the clamp
bracket.
7. Remove the port clamp bracket and tilt tube from the swivel bracket.
8. Remove the two bushings in the swivel bracket.

c a b a- Tilt stop
b- Bolt and washer
c- Tilt bushing
d- Port clamp bracket
e- Tilt tube

e c d

20852

Reverse Lock Hook

Removal
1. Pry the bushing open and remove the reverse lock link from the bushing and reverse lock hook.

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 Clamp/Swivel Bracket, Driveshaft Housing

2. Remove the reverse lock link from the upper shift shaft.

b b

d
c
20928

a- Bushing
b- Reverse lock link
c- Reverse lock hook
d- Upper shift shaft

3. Remove the shoulder bolts securing the reverse lock hook to the swivel bracket.
4. Remove the reverse lock hook, washers on each side, and the spring.

a - Reverse lock hook

b - Shoulder bolt
c - Spring

c a

20830

Installation
1. Install the spring on the swivel housing with the spring loops placed over the bosses on the swivel bracket.
2. Slide the reverse lock hook under the hooks on the spring.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-43

Clamp/Swivel Bracket, Driveshaft Housing

3. Place the flat washers in between the bosses and the reverse lock hook.

b d
c

e
a
a

20832

a- Spring
b- Boss
c- Flat washer (2)
d- Hook on spring
e- Reverse lock hook

4. Install one shoulder bolt on each side of the reverse lock hook. Ensure that the shoulder is properly located in the hole in
the reverse lock hook. Tighten the shoulder bolt to specified torque.

a - Reverse lock hook

b - Shoulder bolt (2)
c - Spring

c a

20830

Description Nm lb. in. lb. ft.

Reverse lock hook shoulder bolt 11 97.3
5. Attach the reverse lock link to the upper shift shaft.

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 Clamp/Swivel Bracket, Driveshaft Housing

6. Install the reverse lock link in the bushing and reverse lock hook and snap the bushing closed

b b

d
c
20928

a- Bushing
b- Reverse lock link
c- Reverse lock hook
d- Upper shift shaft

Reverse Lock Lever

Removal
1. Remove the spring from the spring hook pin.
2. Remove the shoulder bolt.

b a - Reverse lock lever

c b - Shoulder bolt and washer between lever and swivel
bracket
c - Upper lever stop
d - Pin on tilt stop bracket
a e - Spring hook pin
f - Spring
f
d

20834

Installation
1. Attach the reverse lock lever to the starboard clamp bracket with the shoulder bolt, two wave washers, and a flat washer.
Tighten the shoulder bolt to the specified torque.

Description Nm lb. in. lb. ft.

Reverse lock lever shoulder bolt 11 97.3
2. Attach the spring to the reverse lock lever and the spring hook pin.

Tilt Stop Bracket

Removal
1. Remove the two bolts securing the tilt stop plate to the swivel bracket.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-45

Clamp/Swivel Bracket, Driveshaft Housing

2. Remove the spring and pivot guide from the swivel bracket.

a - Tilt stop plate

b - Bolts
a

20838

Reassembly and Installation

1. Install a new plastic bushing on the tilt stop pivot shaft. Position the bushing as shown.

a a - Plastic bushing
b - Tilt stop pivot shaft
b

20846

2. Install a new pivot guide and spring in the swivel bracket. Lubricate the guide with 2‑4‑C with PTFE.

a - Spring
b - Pivot guide

20848

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Tilt stop bracket pivot guide 92-802859A 1
3. Position the tilt stop bracket so the pin is between the reverse lock lever stops.

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 Clamp/Swivel Bracket, Driveshaft Housing

4. Install the plate over the pivot shaft.

5. Secure the plate and tilt stop bracket with two bolts. Tighten bolt to specified torque.

a- Bolts (2)
b- Plate
c- Tilt stop bracket pin
a
d- Reverse lock lever stops

b
d

20850

Description Nm lb. in. lb. ft.

Tilt stop bolts 27 20

Clamp Bracket Installation

1. Install the two bushings in the swivel bracket.
2. Install the port clamp bracket and tilt tube through the swivel bracket.
IMPORTANT: The tilt tube end with fewer threads is assembled to the starboard clamp bracket.
3. Ensure that the tilt stop bracket pin is positioned between the stops on the reverse lock lever.
4. Position the tilt end of stop bracket in the clamp bracket tilt slot.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-47

Clamp/Swivel Bracket, Driveshaft Housing
5. Assemble the port tilt stop with the shoulder and washer to the clamp bracket. Ensure that the shoulder is properly
positioned through the slot in the tilt stop.

h e a

j d e
c f
b g
h

k l

i 20858

a- Port clamp bracket

b- Swivel bracket
c- Shoulder bolt
d- Wave washer
e- Tilt stop
f- Flat washer
g- Port clamp bracket
h- Bushing
i- Tilt stop bracket end
j- Tilt tube
k- Stops on the reverse lock hook
l- Pin

6. Install the starboard clamp bracket on the tilt tube.

7. Position the end of tilt stop bracket in the clamp bracket tilt slot.

20859

8. Install the tilt stop pin and clamp bracket stud.

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 Clamp/Swivel Bracket, Driveshaft Housing
9. Install the starboard side tilt tube locknut.

a a - Tilt tube locknut

b - Clamp bracket stud
c - Tilt stop pin

b
c 20851

10. install the outboard on the transom.

Swivel Bracket/Clamp Bracket Removal

Shift Control Removal - Remote Control Models
1. Remove the two bolts securing the bottom cowl cover and remove the cover.
2. Remove the bolt securing the remote control cable clamp bracket.
3. Remove the cotter pins and washers on the remote control throttle and shift cables.
4. Remove the cotter pins and washers on the shift rod.
5. Remove the shift rod, throttle cable, and shift cable.
6. Loosen the bolts securing the remote control bracket approximately 6 mm (1/4 in.).
7. Slide the shift lever shaft out from the shift lever shaft bracket and remove the upper shift shaft. Refer to Section 7A ‑
Remote Control Models ‑ Shift Control Removal.

Shift Control Removal - Tiller Handle Models

1. Remove the bottom cowl upper clamp. Remove the shift/throttle cables and the throttle link. Refer to Section 7B ‑ Tiller
Handle Removal.
2. Remove the two throttle rods from the throttle lever. Refer to Section 7B ‑ Tiller Handle Removal.
3. Remove the throttle only button retainer clip from the cowl.
4. Remove the retainer, grommet and throttle only button.
5. Remove the three screws securing throttle only assembly to the engine block.
6. Remove the upper shift shaft from the shift lever. Refer to Section 7A ‑ Throttle Only Removal.

Removal
1. Remove the flywheel cover and flywheel. Refer to Section 2A ‑ Flywheel Removal.
2. Attach a chain hoist hook to the powerhead lift eye.

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Clamp/Swivel Bracket, Driveshaft Housing

3. Support the outboard with the chain hoist.

19355

4. Remove the two bolts securing the lower motor mount cover to the driveshaft housing.
5. Remove the locknut from the motor mount bolt.
6. Remove the bolt from the swivel bracket yoke. Refer to Lower Motor Mount Replacement, preceding.
7. Remove the roll pin securing the upper shift shaft to the coupler.
8. Straight the tab on the lock plate for the upper motor mount.
9. Remove the nut securing the upper motor mount.
10. Push the upper shift shaft up through the powerhead assembly until it clears the swivel bracket. Do not pull the upper shift
shaft through the grommet.
NOTE: The upper shift shaft may be held in this position by clamping a Vice Grip® pliers to it.
11. While holding the upper shift shaft, remove the swivel/clamp brackets from the driveshaft housing and adapter plate. Refer
to Upper Motor Mount Replacement, preceding.

Swivel Bracket ‑ Disassembly and Reassembly

Disassembly
1. Raise the swivel bracket to the full up tilt position.
2. Engage the reverse lock lever.
3. Remove the rubber damper from the bottom yoke.
4. Remove the ground cable bolt from the bottom yoke.
5. Remove the snap ring from the steering shaft assembly.

a
a- Rubber damper
b- Bottom yoke
c- Ground cable bolt
d- Steering shaft assembly
b e- Snap ring

20900

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 Clamp/Swivel Bracket, Driveshaft Housing

6. Use a torch lamp to warm the bottom yoke.

7. Use a dead blow hammer to remove the bottom yoke from the steering shaft assembly.

a a - Dead blow hammer

b - Torch lamp
c - Bottom yoke

c b

20901

Torch Lamp 91‑63209

8. Wait until the steering shaft is cool.
9. Remove the washer, O‑ring, and bushing from the steering shaft.
10. Remove the steering shaft from the swivel bracket.

a- Steering shaft
a
b- Swivel bracket
c- Bushing
b d- O‑ring
e- Washer

c
d
e

20902

11. Remove the clamp brackets from the swivel bracket. Refer to Clamp Bracket Removal, preceding.

Reassembly
1. Assemble the clamp brackets to the swivel bracket. Refer to Clamp Bracket Installation, preceding.
2. Install a thrust washer and bushing on the steering arm.

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Clamp/Swivel Bracket, Driveshaft Housing

3. Install the steering shaft assembly in the swivel bracket.

a- Steering shaft assembly

a b- Thrust washer
c- Bushing
b d- Swivel bracket
c

20903

4. Push the steering shaft assembly completely into the steering bracket
5. Install a bushing, O‑ring, and thrust washer.

a- Steering shaft
a
b- Swivel bracket
c- Bushing
b d- O‑ring
e- Washer

c
d
e

20902

6. Align the bottom yoke on the steering shaft.

7. Warm the bottom yoke with the torch lamp.
8. Hold the steering shaft assembly.
9. Use a dead blow hammer to install the bottom yoke on the steering shaft assembly.

c a- Steering shaft assembly

b- Bottom yoke
b c- Torch lamp
a d- Dead blow hammer

20904

Torch Lamp 91‑63209

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 Clamp/Swivel Bracket, Driveshaft Housing

10. Install the snap ring to the steering shaft assembly.

a
a- Rubber damper
b- Bottom yoke
c- Ground cable bolt
d- Steering shaft
b e- Snap ring

20900

11. Install the ground cable to the bottom yoke.

12. Install the rubber damper to the bottom yoke.
13. Disengage the tilt lock lever.
14. Return the swivel bracket to the operating position.
15. Lubricate the swivel bracket and steering shaft with 2‑4‑C with PTFE.

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Swivel bracket and steering shaft 92-802859A 1

Swivel Bracket/Clamp Bracket Installation

Installation
1. Attach a chain hoist hook to the powerhead lift eye.
2. While holding the upper shift shaft, install the swivel/clamp brackets to the driveshaft housing and adapter plate. Refer to
Upper Motor Mount Installation, preceding.
3. Push the upper shift shaft down through the powerhead assembly.
4. Install the nut securing each upper motor mount. Tighten upper motor mount nuts to specified torque.

Description Nm lb. in. lb. ft.

Upper motor mount nut 20.3 179.7
5. Bend the lock plate tab against the nuts to prevent the nut from loosening.
6. Install the roll pin securing the upper shift shaft to the coupler.
7. Install the bolts through the swivel bracket yoke.
8. Install the locknuts on the lower motor mount bolts. Tighten the locknuts to specified torque.

Description Nm lb. in. lb. ft.

Lower motor mount locknut 40 29
9. Install the two bolts securing the lower motor mount covers to the driveshaft housing. Refer to Lower Motor Mount
Installation, preceding.

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Clamp/Swivel Bracket, Driveshaft Housing

10. Remove the chain hoist from the powerhead lift eye.

19355

11. Install the flywheel and flywheel cover. Refer to Section 2A ‑ Flywheel Installation.

Shift Control Installation - Remote Control Models

1. Install the upper shift shaft to the shift lever.
2. Push the shift lever shaft into the shift lever shaft bracket.
3. Tighten the bolts securing the remote control bracket.

Description Nm lb. in. lb. ft.

Remote control bracket bolts 6 53
4. Install the shift rod, throttle cable, and shift cable.
5. Install the cotter pins and washers on the shift rod.
6. Install the cotter pins and washers on the remote control throttle and shift cables.
7. Install the bolt securing the remote control cable clamp bracket. Refer to Section 7A ‑ Remote Control Models ‑ Shift
Control Installation, preceding.
8. Install the bottom cowl cover and secure with three bolts.

Shift Control Installation - Manual Tilt Models

1. Install the upper shift shaft into the shift lever.
2. Install the throttle only assembly to the shift lever shaft.
3. Attach the throttle only assembly to the powerhead with three bolts. Tighten the bolts to specified torque.
4. Install the throttle only button, grommet, and retainer.
5. Install the throttle only retaining clip. Refer to Section 7A ‑ Throttle Only Installation.

Description Nm lb. in. lb. ft.

Throttle only attaching bolts (3) 6 53
6. Install the throttle link to the throttle lever. Refer to Section 7B ‑ Tiller Handle.
7. Install the throttle cables to the throttle only pulley. Refer to Section 7B ‑ Tiller Handle.
8. Install the grommet and bottom cowl upper clamp. Refer to Section 7B ‑ Tiller Handle.

Gearcase/Reverse Hook Operation

Operation
1. Rotate the shift handle grip to the neutral position. Ensure that the following conditions are met:
• Gearcase is in neutral (propeller rotates in both directions).
• Resistance should not be felt when the propeller shaft is rotated in either direction.

Page 5A-54 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Clamp/Swivel Bracket, Driveshaft Housing

• Neutral start interlock lever is centered, allowing starter sheave to rotate.

• Reverse hook is engaged.
2. Rotate the shift handle grip to the forward position. Ensure that the following conditions are met:
• Gearcase is in forward gear. The gear housing should ratchet when the propeller shaft is turned clockwise and
resistance should be felt when the propeller is turned counterclockwise.
• Neutral start interlock lever is engaged preventing starter sheave rotation.
• Reverse hook is disengaged.
3. Rotate the shift handle grip to the reverse position. Ensure that the following conditions are met:
• Gearcase is in reverse gear. Resistance should be felt when the propeller shaft is rotated in either direction.
NOTE: It may be necessary to rotate propeller shaft when shifting to reverse gear.
• Neutral start interlock lever is engaged.
• Reverse hook is engaged.

Adjustments
1. Lower shift shaft and coupler adjustments: Refer to Section 6A ‑ Gear Housing Installation.
2. Throttle cable adjustments: Refer to Section 7B ‑ Throttle Cable/Linkage Adjustments.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5A-55

Clamp/Swivel Bracket, Driveshaft Housing

Notes:

Page 5A-56 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Mid-Section
Section 5B - Power Trim
Table of Contents
Power Trim Specifications................................................. 5B-2 Electrical System Troubleshooting........................... 5B-11
Power Trim/Tilt Components............................................. 5B-4 Power Trim Removal....................................................... 5B-18
Power Trim General Information........................................5B-6 Power Trim Installation.................................................... 5B-19
General Information.................................................... 5B-6 Manual Release Valve Removal and Repair................... 5B-20
Power Trim Operation.................................................5B-6 Power Trim Motor............................................................ 5B-21
Checking Power Trim Fluid.........................................5B-7 Power Trim Motor Removal...................................... 5B-21
Purging Power Trim System....................................... 5B-7 Power Trim Motor Disassembly, Inspection and
Manual Tilting............................................................. 5B-7 Repair....................................................................5B-22
Trailering Boat/Outboard ........................................... 5B-7 Power Trim Motor Reassembly................................ 5B-24
Wire Color Code Abbreviations..........................................5B-8
Theory of Operation........................................................... 5B-9
Power Trim Motor Installation................................... 5B-25
Power Trim Pump............................................................ 5B-27 5
B
Power Trim Hydraulic Diagram...................................5B-9 Power Trim Pump Disassembly................................5B-27
Operation.................................................................. 5B-10 Power Trim Pump Reassembly................................ 5B-28
Troubleshooting the Power Trim System.........................5B-10 Power Trim Cylinder........................................................ 5B-31
Preliminary Troubleshooting Steps...........................5B-10 Power Trim Cylinder Disassembly............................5B-31
Hydraulic System Troubleshooting........................... 5B-10 Power Trim Cylinder Reassembly............................ 5B-34

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-1

Power Trim

Power Trim Specifications

Power Trim Specifications
Trim up circuit pressure, maximum 13820 to 18430 kPa (2000 to 2675 psi)
Trim down circuit pressure 6500 to 8160 kPa (940 to 1180 psi)
System fluid Power Trim and Steering Fluid or Automatic Transmission Fluid (ATF) (Type Dexron III)
System fluid capacity 263 ml (8.9 fl oz)
Power trim and tilt motor
Voltage 12 VDC
Continuous run 60 seconds or less
Output 130 watts
Direction of revolution Forward/reverse
Circuit breaker
Type Bimetal
30 seconds or less 25 °C (77 °F)
On/reset time
20 seconds or more (25 A)
Brush length 10.0 mm (0.39 in.)
Wear limit 6.0 mm (0.236 in.)
Commutator
Outer diameter 19.5 mm (0.768 in.)
Outer diameter wear limit 18.5 mm (0.728 in.)
Depth of undercut 1.3 mm (0.051 in.)
Depth of undercut limit 0.8 mm (0.031 in.)
Tilt cylinder
Piston diameter 32.0 mm (1.260 in.)
Tilt rod diameter 12.5 mm (0.492 in.)
Stroke 140.0 mm (5.51 in.)

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
7 Loctite 271 Threadlocker Cylinder rod threads 92-809819
Power trim system
28 Dexron III Automatic Obtain Locally
Power trim assembly O-rings
Power trim system
Power Trim and Steering Power trim assembly O-rings
114 92-858074K01
Fluid Power trim system reservoir
Power trim cylinder O-rings

Special Tools
DMT 2004 Digital Multimeter 91‑892647A01

Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC

V Hz
H z TEMP
mA
A
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
mV IG
OFF IP

TEMP

A mA COM V Hz

4516

Page 5B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-3

Power Trim

Power Trim/Tilt Components

2
3
4
5

1 6

33
7 35
32
34

8
10
31

37
9
36
30
39
11
29
12 28
38
27
13
14
26
25
24
23
22
21
20
16
17
18

15 19
16674

Page 5B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Power Trim/Tilt Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Power trim/tilt assembly
2 1 Rod eye
3 1 Nut 35 25.8
4 1 Seal
5 1 O‑ring
6 1 Cylinder 155 114
7 1 O‑ring
8 1 Tube
9 1 O‑ring
10 1 Piston rod assembly
11 1 O‑ring
12 1 Piston
13 1 Ring
14 1 O‑ring
15 1 Manual release valve assembly
16 1 Seal set
17 1 O‑ring
18 1 Seal
19 1 Snap ring
20 1 Snap ring
21 1 Valve seat
22 1 Ball
23 1 Spring seat
24 1 Spring
25 2 O‑ring
26 1 Pump
27 1 Coupling
28 3 Bolt 5.2 46
29 1 O‑ring
30 1 Motor assembly
31 1 O‑ring
32 1 Reservoir tank
33 1 Cap assembly 1.5 13
34 1 O‑ring
35 2 Screw 5.2 46
36 1 PTT switch
37 1 O‑ring
38 1 Switch bracket
39 2 Screw (M6 x 16) 5.2 46

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-5

Power Trim

Power Trim General Information

General Information
The power trim system consists of an electric motor, pressurized fluid reservoir, pump, and trim cylinder. Trim the outboard
through the entire trim and tilt range several times to remove any air from the system.
The remote control or trim panel is equipped with a switch used to trim the outboard up or down, tilt the outboard for shallow
water operation at slow speeds, or for trailering. The outboard can be trimmed up or down while under power or when the
engine is not running.

Power Trim Operation

With most boats, operating around the middle of the trim range will give satisfactory results. However, to take full advantage of
the trimming capability there may be times when you choose to trim your outboard all the way in or out. Along with an
improvement in some performance aspects comes a greater responsibility for the operator, and this is being aware of some
potential control hazards.
The most significant control hazard is a pull or torque that can be felt on the steering wheel or tiller handle. This steering torque
results from the outboard being trimmed so the propeller shaft is not parallel to the water surface.

! WARNING
Trimming the outboard beyond a neutral steering condition may result in a pull on the steering wheel or tiller handle and loss
of boat control. Maintain control of the boat if trimming beyond a neutral steering condition.

Consider the following lists carefully.

1. Trimming in or down can:
• Lower the bow.
• Result in quicker planing off, especially with a heavy load or a stern heavy boat.
• Generally improve the ride in choppy water.
• Increase steering torque or pull to the right (with the normal right‑hand rotation propeller.)
• In excess, can lower the bow of some boats to a point where they begin to plow with their bow in the water while on
plane. This can result in an unexpected turn in either direction (called bow steering or oversteering) if any turn is
attempted, or if a significant wave is encountered.

! WARNING
Operating the boat at high speeds with the outboard trimmed too far under can create excessive bow steer, resulting in the
operator losing control of the boat. Install the trim limit pin in a position that prevents excessive trim under and operate the
boat in a safe manner.
• In rare circumstances, the owner may decide to limit the trim in. This can be accomplished by purchasing a stainless
steel tilt pin from your dealer and inserting it in whatever adjustment hole in the transom brackets is desired. The
nonstainless steel shipping bolt should not be used in this application other than on a temporary basis.
2. Trimming out or up can:
• Lift the bow higher out of the water.
• Generally increase top speed.
• Increase clearance over submerged objects or a shallow bottom.
• Increase steering torque or pull to the left at a normal installation height (with the normal right‑hand rotation propeller.)
• In excess, can cause boat porpoising (bouncing) or propeller ventilation.
• Cause engine overheating if any cooling water intake holes are above the waterline.

Page 5B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Checking Power Trim Fluid

1. Tilt the outboard to the full up position and engage the tilt support lock.

9703

2. Remove the fill cap and check the fluid level. The fluid level should be even with the bottom of the fill hole. Add Quicksilver
or Mercury Precision Lubricants Power Trim and Steering Fluid. If not available, use automotive (ATF) automatic
transmission fluid.

9701

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system 92-858074K01
Fluid

Purging Power Trim System

IMPORTANT: The fill cap with O‑ring must be tightened securely before operating the power trim system.
IMPORTANT: Operate the power trim system in short spurts until the hydraulic pump is primed and the trim cylinders move.
• Cycle the outboard through the entire trim/tilt range four times.
• To check for presence of air in the system, extend cylinders slightly and push down on outboard. If the trim rams retract
more than 3 mm (0.125 in.), air is present. Cycle trim system again and repeat this step.
• Check fluid level. Refer to Checking Power Trim Fluid.

Manual Tilting
If the outboard cannot be tilted using the power trim/tilt switch, the outboard can be manually tilted.
NOTE: The manual tilt release valve must be tightened before operating the outboard to prevent the outboard from tilting up
during reverse operation.
Turn out the manual tilt release valve three turns counterclockwise. This allows manual tilting of the outboard. Tilt the outboard
to the desired position and tighten the manual tilt release valve.

9976

Trailering Boat/Outboard
Trailer your boat with the outboard tilted down in a vertical operating position.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-7

Power Trim
If additional ground clearance is required, the outboard should be tilted up using an accessory outboard support device. Refer
to your local dealer for recommendations. Additional clearance may be required for railroad crossings, driveways, and trailer
bouncing.

21997

IMPORTANT: Do not rely on the power trim/tilt system or tilt support lever to maintain proper ground clearance for trailering.
The outboard tilt support lever is not intended to support the outboard for trailering.
Shift the outboard to forward gear. This prevents the propeller from spinning freely.

Wire Color Code Abbreviations

Wire Color Abbreviations
BLK Black BLU Blue
BRN Brown GRY Gray
GRN Green ORN or ORG Orange
PNK Pink PPL or PUR Purple
RED Red TAN Tan
WHT White YEL Yellow
LT or LIT Light DK or DRK Dark

Page 5B-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Theory of Operation
Power Trim Hydraulic Diagram
o n m

l
k
q p

h i j

g
r
f

e c d
a b 17175

a- Reservoir
b- Filter
c- Electric motor
d- Trim up inlet check valve
e- Trim down inlet check valve
f- Down circuit relief valve
g- Hydraulic pump
h- Trim up pressure operated check valve
i- Up circuit relief valve and shuttle valve
j- Trim down pressure operated check valve
k- Return valve
l- Trim cylinder
m- Impact relief valve
n- Shock piston
o- Memory piston
p- Up circuit thermal relief valve
q- Down circuit thermal relief valve
r- Manual release valve

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-9

Power Trim

Operation
Trim Circuit - Up
When the trim up circuit is activated, the electric motor rotates the hydraulic pump. As the pump gears rotate, fluid is drawn
through a check valve and into the pump inlet. The fluid passes through a check valve, then passes through a pressure
operated (PO) check valve and to the bottom of the trim cylinder. The fluid pushes the cylinder piston out, trimming the engine
up. Oil, from the top side of the cylinder, returns through a passage in the cylinder wall to the inlet side of the pump. In this
mode, as the trim ram extends, up pressure increases to 16,080 kPa (2330 psi) and opens the up pressure relief valve. When
the engine is not running, the outboard may be tilted to the full up position by opening the manual release valve.

Trim Circuit - Down

When the down circuit is activated, the electric motor rotates in the opposite direction. As the pump gears rotate, fluid is drawn
through a check valve and into the pump inlet. The fluid passes through a check valve and to the top of the trim cylinder. The
fluid pushes the cylinder piston down and lowers the engine. Oil, from the bottom side of the cylinder, returns to the inlet side of
the pump. As the trim cylinder retracts to its limit, down pressure is limited to 7350 kPa (1070 psi) by an orifice in the down
pressure circuit.

Trail Over System

Should the outboard motor strike a submerged object, while in forward motion, hydraulic pressure on the top side of the
cylinder will increase to cause the impact relief valve in the trim cylinder to open. This allows the lower unit to trail over the
obstruction. The fluid in the top side of the cylinder opens the impact relief valve and flows into the cavity between the memory
piston and the cylinder piston. When the lower unit clears the submerged object, the thrust of the engine forces the engine back
down. As the cylinder piston is lowered, fluid trapped between the memory piston and the cylinder piston escapes through a
return check valve. Fluid below the memory piston is trapped in place, stopping the cylinder piston and returning the outboard
to its previous trim position.

Troubleshooting the Power Trim System

Preliminary Troubleshooting Steps
Determine if the problem is hydraulic or electrical related. Most often, if the electric motor operates, the problem is in the
hydraulic system. If the electric motor does not operate, the problem is in the electrical system.
IMPORTANT: Operate the power trim system after each check to see if the problem is corrected. If problem has not been
corrected, proceed with the next check.
1. Check that the manual release valve is tightened fully, (clockwise).
2. Check the power trim pump fluid level in the full up position. Fill if necessary. Refer to Checking Power Trim Fluid and
Purging Power Trim System in this section.
3. Check for external leakage in the power trim system. Replace/repair the defective component if a leak is found. Maximum
acceptable power trim cylinder leak down is 25 mm (1 in.) within a 24 hour period.

Hydraulic System Troubleshooting

Condition/Problem
Condition of Trim System Problem
Trim motor runs; trim system does not move up or down. 1, 2, 5, 8
Does not trim full down; up trim OK. 2, 4, 5, 11, 12
Does not trim full up; down trim OK. 1, 2, 3, 4, 6, 10, 12
Partial or jerky down/up. 1, 3, 6
Leaks down and does not hold trim. 3, 4, 5
Trim motor working hard and trims slow up and down. 2, 7, 8, 9
Trims up very slow. 1, 2, 6, 7, 8, 9, 10, 12
Starts to trim up from full down position when the down trim button is depressed. 3, 4
Trim position does not hold in reverse. 2, 3, 4, 5, 12

Page 5B-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Problem/Solution
No. Problem Solution
1. Low fluid level. Add Power Trim and Steering Fluid or ATF (Type Dexron III).
2. Defective hydraulic pump. Replace pump assembly.
Trim cylinder piston or memory piston O‑rings
3. Replace trim cylinder piston and memory piston O‑rings.
leaking or cut.
Manual release valve leaking (check condition of
4. Ensure that valve is fully closed. Inspect O‑rings.
O‑rings) (valve not fully closed).
5. Debris in system. Inspect for debris. Refill system with clean fluid.
6. Battery low. Check battery.
7. Electric motor defective. Refer to Electrical System Troubleshooting.
8. Broken motor/pump driveshaft. Inspect for damage.
9. Air pocket under pump. Purge system. Refer to Purging the Power Trim System preceding.
10. Defective up relief valve. Inspect components. Refer to Power Trim Pump Disassembly.
11 Trim cylinder shock piston ball not seated. Inspect ball seat for nicks and debris.
12 Thermal relief valve not seated. Replace manual relief valve.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system 92-858074K01
Fluid
28 Dexron III Automatic Power trim system Obtain Locally

Electrical System Troubleshooting

General Checks
Before troubleshooting the power tilt electrical system, check the following:
• Disconnected wires
• Connections are tight and corrosion free
• Plug‑in connections are fully engaged
• Battery is fully charged

Condition/Problem
Condition of Trim System Problem No.
Trim motor does not run when trim button is depressed. 1, 2, 4, 5, 6, 7
Trim system trims opposite of buttons. 3
Tiller handle mounted trim buttons do not activate trim system. 2, 4, 5, 6

Problem/Solution
No. Problem Solution
1. Battery low or discharged. Check battery.
2. Open circuit in trim wiring. Check for an open connection.
3. Wiring reversed in remote control, handle switch or trim leads. Verify connections.
4. Wire harness corroded through. Replace wire harness.
5. Internal motor problem (brushes, shorted armature). Check for open connection. Replace motor.
6. Trim switch failure. Replace switch.
Verify relays are functioning correctly. Check voltage at
7. Relay not operating.
trim bullets.

DMT 2004 Digital Multimeter 91‑892647A01

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-11

Power Trim

Power Trim Relay Test Procedure

a b a - Green heavy gauge pump wire/green

relay terminal (down)
b - Blue heavy gauge pump wire/blue relay
terminal (up)

20926

The trim motor relay system used on permanent magnet trim systems connect each of the two wires from the trim motor to
either ground or positive in order to allow the motor to run in both directions.
If the motor will not run in the up direction, it may be either the up relay is not making contact to 12 volts, or the down relay is
not making contact to ground. The opposite is true if the system will not run down. When the system is not energized, both
relays should connect the heavy motor leads to ground.
To test which relay is faulty if the trim system does not operate in one direction:
1. Disconnect the heavy gauge pump wires from the trim control relay.
2. Check for continuity between each relay terminal and ground.

DMT 2004 Digital Multimeter 91‑892647A01

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Green relay terminal Ground Full continuity (R x 1) < 20 Ω
Blue relay terminal Ground Full continuity (R x 1) < 20 Ω
3. Replace the relay that does not have continuity.
4. Connect a voltmeter to the blue relay terminal and to ground. There should be 12 volts on the blue lead when the up switch
is pushed.
5. Connect a voltmeter to the green relay terminal and to ground. There should be 12 volts on the green lead when the down
switch is pushed.

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Green relay terminal Ground Voltage ‑ DC Battery voltage (12V)
Blue relay terminal Ground Voltage ‑ DC Battery voltage (12V)
6. Replace the relay that does not switch the lead to positive.
7. Reconnect the heavy gauge pump wires to the trim control relay.

Page 5B-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Power Trim Electrical Circuit - Remote Control

a b c d
BLK BLK

3 f

LT BLU
PNK
e

RED
RED
6

RED
GRN
BLK

RED
BLK
2
GRN

5
BLK

5 BLK
g

BLU
RED

RED
RED
BLK

RED
5

RED

9
5
LT BLU
RED

PNK

RED
RED

BLK
RED
1
RED

RED

8
h
LT BLU

PNK
GRN
BLU

k
PNK
LT BLU
i
BRN/WHT

RED
RED

E P
F D N
PNK C
G M
LT BLU A B
RED RED H L
J K
LT BLU

PNK
RED

j l E P
F D N
5 G
C
M
A
LT BLU

B
RED
PNK

H L
J K
m
7 o
n 4
18511

a- Down power trim relay

b- Up power trim relay
c- Starter relay
d- Fuse
e- To rectifier
f- Starter motor
g- Remote control
h- Battery
i- Fourteen pin engine harness connector
j- Power trim cowl switch

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-13

Power Trim

k- Power trim unit

l- Red wire (pin A)
m- Light blue wire (pin H)
n- Pink wire (pin J)
o- Brown/white wire (pin K)

Page 5B-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Power Trim Electrical Circuit - Tiller Handle

a b c d
BLK BLK

LT BLU
PNK
e f

RED
RED

RED
GRN
BLK

RED
BLK
5 2 5 6
GRN
BLK

BLK

BLU
RED

RED
BLK

RED

9
LT BLU

PNK
RED

BLK
RED
1
RED

RED

8
g
LT BLU

PNK
GRN
BLU

UP

DN
h
LT BLU
PNK

RED

18512

a- Down power trim relay

b- Up power trim relay
c- Starter relay
d- Fuse
e- To rectifier
f- Starter motor

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-15

Power Trim

g - Battery
h - Tiller handle trim switch
i - Power trim unit

Troubleshooting the Down Circuit

NOTE: Refer to the preceding wiring diagrams for test points when troubleshooting the electrical systems. Test points are
specified by number.

DMT 2004 Digital Multimeter 91‑892647A01

Step Test Procedure Test Result

Battery voltage measured:
Step 1: Check for Connect voltmeter red lead to point 1 • Remote control models: Go to Step 2.
battery voltage at and black lead to battery ground. • Tiller handle models: Go to Step 4.
point 1. Depress the down trim button. No battery voltage measured:
• Go to Step 3.
Battery voltage measured:
• Go to Step 5.
Step 2: Check for No battery voltage measured:
Connect voltmeter red lead to point 3
battery voltage at • There is an open circuit between Point 3 and positive (+)
and black lead to battery ground.
point 3. battery terminal.
• Check for loose or corroded connections.
• Check wires for open.
Battery voltage measured:
Step 3: Check for Connect voltmeter red lead to point 4
• Wire is open between Points 4 and 1.
battery voltage at and black lead to battery ground.
No battery voltage measured:
point 4. Depress the down trim button.
• Go to Step 4.
Battery voltage measured:
Step 4: Check for Connect voltmeter red lead to each • Trim switch is faulty. Verify by performing continuity test.
battery voltage at point 5 and black lead to battery No battery voltage measured:
each point 5. ground. • Check for loose or corroded wire at each point 5.
• Open circuit in wire supplying current to point 5.
Battery voltage measured:
Step 5: Check for Connect voltmeter red lead to point 2
• Go to Step 6.
battery voltage at and black lead to battery ground.
No battery voltage measured:
point 2. Depress the down trim button.
• Relay is defective.
Relay is good:
• Pump motor wiring is defective.
Step 6: Check up Test up relay. Refer to Power Trim
relay. Relay Test, preceding. • Pump motor is defective.
Relay is faulty:
• Replace relay.

Troubleshooting the Up Circuit

NOTE: Refer to the preceding wiring diagrams for test points when troubleshooting the electrical systems. Test points are
specified by number.

DMT 2004 Digital Multimeter 91‑892647A01

Step Test Procedure Test Result

Battery voltage measured:
Step 1: Check for Connect voltmeter red lead to point 8 • Remote control models: Go to Step 2.
battery voltage at and black lead to battery ground. • Tiller handle models: Go to Step 4.
point 8. Depress the up trim button. No battery voltage measured:
• Go to Step 3.

Page 5B-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Step Test Procedure Test Result

Battery voltage measured:
• Go to Step 5.
Step 2: Check for No battery voltage measured:
Connect voltmeter red lead to point 3
battery voltage at • There is an open circuit between Point 3 and positive (+)
and black lead to battery ground.
point 3. battery terminal.
• Check for loose or corroded connections.
• Check wires for open.
Battery voltage measured:
Step 3: Check for Connect voltmeter red lead to point 7
• Wire is open between points 7 and 8.
battery voltage at and black lead to battery ground.
No battery voltage measured:
point 7. Depress the up trim button.
• Go to Step 4.
Battery voltage measured:
Step 4: Check for Connect voltmeter red lead to each • Trim switch is faulty. Verify by performing continuity test.
battery voltage at point 5 and black lead to battery No battery voltage measured:
each point 5. ground. • Check for loose or corroded wire at each point 5.
• Open circuit in wire supplying current to point 5.
Battery voltage measured:
Step 5: Check for Connect voltmeter red lead to point 6
• Go to Step 6.
battery voltage at and black lead to battery ground.
No battery voltage measured:
point 6. Depress the up trim button.
• Relay is defective.
Relay is good:
• Pump motor wiring is defective.
Step 6: Check up Test down relay. Refer to Power Trim
relay. Relay Test preceding. • Pump motor is defective.
Relay is faulty:
• Replace relay.

Troubleshooting the Down and Up Circuits (All Circuits Inoperative)

NOTE: Refer to the preceding wiring diagrams for test points when troubleshooting the electrical systems. Test points are
specified by number.

DMT 2004 Digital Multimeter 91‑892647A01

Step Test Procedure Test Result

Fuse blown:
• Correct problem that caused fuse to blow, and
Step 1: Check Visually inspect power trim motor
fuse. fuse. • Replace fuse.
Fuse not blown:
• Go to Step 2.
No battery voltage:
Step 2: Check • Check battery leads for poor connections or open circuit.
Connect voltmeter red lead to point
battery • Check battery charge.
3 and black lead to battery ground.
voltage. Battery voltage measured:
• Go to Step 3.
No battery voltage:
• Go to Step 4.
Connect voltmeter red lead to point Battery voltage measured:
Step 3: Up
8 and black lead to battery ground.
trim switch. • Check black ground wires for connection or poor ground at point
Depress up trim button.
10.
• Pump motor is faulty.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-17

Power Trim

Step Test Procedure Test Result

No voltage measured:
• Go to Step 5.
Battery voltage measured:
• Trim switch is faulty or
Connect voltmeter red lead to each • Open circuit in wires (grn/wht or blu/wht) between trim buttons and
Step 4: Open
point 5 and black lead to battery trim pump motor.
circuits.
ground.
• Check
• Trim switch.
• All trim harness connections for loose or corroded connections.
• Pinched or severed wires.
No voltage measured:
Check that voltage is being
supplied to control by performing • Red wire is open between point 3 and red terminal on back of
the following checks: ignition switch.
Step 5: Check Do not start engine. • Check for loose or corroded connections.
voltage. Turn ignition switch to "RUN" • Check for open in wire.
position. Battery voltage measured:
Check for voltage at any instrument
• There is an open circuit between point 5 and red terminal on back
using a voltmeter.
of ignition switch.

Power Trim Removal

1. Tilt the outboard to the full up position and engage the tilt stop mechanism.

a - Tilt stop engaged

10509

2. Remove the trim cylinder rod pin retaining screw and washer.
3. Push the trim cylinder rod pin through the bore from the port side.

a - Tilt cylinder rod pin retaining screw and

washer
b - Tilt cylinder rod pin

a
b

10514

Page 5B-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

4. Retract the power trim cylinder rod.

5. Disconnect the battery cables from the battery.
6. Disconnect the power trim electrical wires from the relays.
7. Remove the ground strap.
8. Remove the port side snap ring and washer from the power trim pivot pin.

a- Snap ring
b- Pivot pin
c- Washer
d- Power trim assembly

d
10516

9. Use a drift punch to remove the pivot pin from the power trim assembly.
10. Remove the power trim assembly from clamp brackets.

Power Trim Installation

1. Install the power trim assembly between the clamp brackets.
2. Install the lower pivot pin through the clamp brackets and power trim assembly.
3. Install the port side snap ring and washer to the power trim pivot pin.

a- Snap ring
b- Pivot pin
c- Washer
d- Power trim assembly

d
10516

4. Install the ground strap.

5. Connect the battery cables to the battery.
6. Extend the power trim cylinder rod until it aligns with the hole in the tilt bracket. Engage the tilt lock.
7. Push the trim cylinder rod pin through the bore from the port side.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-19

Power Trim
8. Install the trim cylinder rod pin retaining screw and washer.

a - Tilt cylinder rod pin retaining screw and

washer
b - Tilt cylinder rod pin

a
b

10514

9. Trim the outboard through the entire trim and tilt range several times to remove any air from the system.
10. Check the power trim fluid level.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system 92-858074K01
Fluid

Manual Release Valve Removal and Repair

! CAUTION
Contamination can damage the hydraulic system or cause the system to malfunction. Failure of power trim or steering
components can result in injury or product damage. Ensure that the work area, shop tools and all components are clean and
lint free during reassembly.

1. Slowly remove the power trim reservoir fill plug.

2. Drain the power trim fluid into a suitable container.
3. Remove the snap ring from the power trim assembly.
4. Remove the manual release valve by turning the valve counterclockwise.
NOTE: Additional fluid may be present in the reservoir. Place a drain pan under the power trim unit when removing the
manual release valve.

a- Fill plug
b- Manual release valve
a b c d c- Snap ring
d- Power trim assembly

10550

5. Remove and discard the two O‑rings and backup ring from the manual release valve.

Page 5B-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
6. Remove and discard the sealing washer from inside the manual release valve cavity.

a b c d a- Manual release valve

b- Backup ring
c- O‑ring
d- O‑ring

10558

7. Install the new sealing washer in the manual release valve cavity.
NOTE: Replace all O‑rings with new O‑rings when reassembling the power trim assembly. Lubricate O‑rings with clean
Power Trim and Steering Fluid or Automatic Transmission Fluid (ATF) (Type Dexron III) prior to installation.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim assembly O-rings 92-858074K01
Fluid
28 Dexron III Automatic Power trim assembly O-rings Obtain Locally
8. Install two new O‑rings and backup ring on the manual release valve.
9. Install the manual release valve into the valve body.
10. Install the snap ring. Ensure that the snap ring is fully seated in the snap ring groove.
11. Add Power Trim and Steering Fluid to the recommended level.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system reservoir 92-858074K01
Fluid

Power Trim Motor

Power Trim Motor Removal
1. Remove the power trim unit from the outboard. Refer to Power Trim Removal preceding.
2. Slowly remove the power trim reservoir tank fill plug.
3. Drain the power trim fluid into a suitable container.

a a - Reservoir tank fill plug

11544

4. Remove the cable tie securing the trim motor harness.

5. Remove the two 4 mm internal hex screws securing the motor assembly to the power trim pump and cylinder assembly.
6. Separate the reservoir tank from the power trim pump and cylinder assembly.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-21

Power Trim
NOTE: Additional fluid may be present in the reservoir. Place a drain pan under the power trim unit when removing the
reservoir.

a- Cable tie
b- Power trim reservoir tank
c- Reservoir attaching screw
a d- Power trim assembly

c c
d

11545

Power Trim Motor Disassembly, Inspection and Repair

Motor Housing Cover Removal
1. Remove the two cross slotted screws securing the motor housing cover to the motor bracket assembly.

a- Motor housing cover

b- Screws (2)
a c- Armature
d- Motor bracket assembly
b

11555

11426

2. Remove the armature from the motor bracket.

Test for Short

Test the armature on a Growler. Follow Growler manufacturer's test instructions. Indication of a short requires replacement of
the armature.

Page 5B-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Test for Ground

1. Use a DMT 2004 Digital Multimeter or ohmmeter (R x 1 scale). Place one lead of meter on the armature shaft and the
other lead on the commutator. If continuity is indicated, armature is grounded and must be replaced.

a- DMT 2004 Digital Multimeter

b- Armature
c- Commutator
d- Armature shaft
a

c
b

d
11421

DMT 2004 Digital Multimeter 91‑892647A01

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Commutator Armature shaft Rx1 No continuity (OUCH)

Checking and Cleaning Commutator

1. Inspect the commutator. If the commutator is worn, it can be turned down on an armature conditioner tool or on a lathe.
2. Clean the commutator with number 00 sandpaper.

Field Tests
IMPORTANT: The commutator end of the armature must be installed in the brushes when performing the following tests.

DMT 2004 Digital Multimeter 91‑892647A01

Meter Test Leads Meter Scale Reading (Ω)

Red Black
Green motor wire Blue motor wire Rx1 0
Green motor wire Motor bracket Rx1 No continuity (OUCH)
Blue motor wire Motor bracket Rx1 No continuity (OUCH)

1. If specific readings are not obtained, check for:

• Defective armature
• Dirty or worn brushes
• Dirty or worn commutator
2. If defective components are found, repair or replace the component and retest.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-23

Power Trim

Brush Inspection
Brush replacement is required if the brushes are pitted, chipped, or if the distance between the brush pigtail and end of the
brush holder slot is less than specification.

a - End of pigtail
b - End of brush holder slot
b c - Distance

c
a

11548

Brush length
End of pigtail to end of the brush holder slot 1.6 mm (0.063 in.)

Power Trim Motor Reassembly

1. Hold the brushes in the slots while installing the armature in the motor bracket assembly.
2. Install an O‑ring on the motor bracket assembly.

a- Armature
b- Motor bracket assembly
c- Brush
d- O‑ring

c b

d
17159

Page 5B-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
3. Use pliers or Vice Grip® pliers to secure the armature shaft before installing the motor cover.

17190

4. Install the motor cover over the armature.

5. Secure the cover to the motor bracket with two cross slotted screws. Tighten screws to the specified torque.

a- Motor housing cover

b- Screws (2)
a c- Armature
d- Motor bracket assembly
b

11426

Description Nm lb. in. lb. ft.

Motor cover screws 5.2 46

Power Trim Motor Installation

1. Ensure that the pump/motor coupling is installed in the pump.

a a - Power trim pump

b - Pump assembly mounting screws (4 mm internal hex)
c - Pump/motor coupling

c
b
10961

2. Align the pump shaft tang with the slot in the pump/motor coupler.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-25

Power Trim
3. Attach the motor assembly to the power trim pump and cylinder assembly.
NOTE: Position the trim motor assembly with the wire harness next to the trim cylinder.
4. Install an O‑ring on the electric motor bracket.

a- Electric motor assembly

b- O‑ring
c- Power trim pump and cylinder assembly
d- Electric motor wire harness

a
d
b

10957

Description Nm lb. in. lb. ft.

Electric motor mounting screws 5.2 46
5. Install the reservoir tank over the electric motor and onto the pump and cylinder assembly.
6. Install two 4 mm internal hex screws. Tighten screws to the specified torque.
7. Secure the wire harness to the reservoir cover with a cable tie.
8. Fill the power trim system with Power Trim and Steering Fluid.

a a- Reservoir tank
b- Fill plug
c- Cable tie
d- Reservoir tank mounting screws (4 mm internal hex)

10954

Description Nm lb. in. lb. ft.

Power trim reservoir tank attaching screws (4 mm internal hex) 5.2 46

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system reservoir 92-858074K01
Fluid

Page 5B-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

Power Trim Pump

Power Trim Pump Disassembly
! CAUTION
Contamination can damage the hydraulic system or cause the system to malfunction. Failure of power trim or steering
components can result in injury or product damage. Ensure that the work area, shop tools and all components are clean and
lint free during reassembly.

1. Remove the power trim unit from the outboard. Refer to Power Trim Removal preceding.
2. Slowly remove the power trim reservoir tank fill plug.
3. Drain the power trim fluid into a suitable container.

a a - Reservoir tank fill plug

11544

4. Remove the cable tie securing the trim motor harness.

5. Remove the two 4 mm internal hex screws securing the reservoir tank to the assembly.
6. Separate the reservoir tank from the power trim assembly.
NOTE: Additional fluid may be present in the reservoir. Place a drain pan under the power trim unit when removing the
reservoir.

a a- Reservoir tank
b- Fill plug
c- Cable tie
d- Reservoir mounting screws (4 mm internal hex)

10954

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-27

Power Trim
7. Remove the electric motor assembly from the trim pump housing.

a- Electric motor assembly

b- O‑ring
c- Power trim pump and cylinder assembly
d- Electric motor wire harness

a
d
b

10957

8. Remove the pump/motor coupling.

9. Remove the three internal hex screws securing the power trim pump to the power trim assembly.

a a - Power trim pump

b - Pump assembly mounting screws (4 mm internal hex)
c - Pump/motor coupling

c
b
10961

10. Remove the up relief valve components and O‑rings from the power trim housing.

a- O‑ring
b- Relief valve assembly
a c- O‑ring
d- Valve seat
e- Ball
b f- Spring guide
g- Spring

g f e d c

10965

Power Trim Pump Reassembly

1. Install two new lubricated O‑rings into the power trim housing.
2. Install a new lubricated O‑ring onto the check valve seat.

Page 5B-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
3. Install the relief valve components into the power trim housing.

a- O‑ring
b- Relief valve assembly
a c- O‑ring
d- Valve seat
e- Ball
b f- Spring guide
g- Spring

g f e d c

10965

4. Assemble the pump to the base with three internal hex screws.
5. Install the pump/motor coupling into the pump.

a a - Power trim pump

b - Pump assembly mounting screws (4 mm internal hex)
c - Pump/motor coupling

c
b
10961

Description Nm lb. in. lb. ft.

Pump mounting screws 5.2 46
6. Align the pump shaft tang with the slot in the pump/motor coupler.
7. Attach the motor assembly to the power trim pump and cylinder assembly.
NOTE: Position the trim motor assembly with the wire harness next to the trim cylinder.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-29

Power Trim
8. Secure the motor assembly to the power trim pump and cylinder assembly with two cross slotted screws. Tighten the
screws to the specified torque.

a- Electric motor assembly

b- O‑ring
c- Power trim pump and cylinder assembly
d- Electric motor wire harness

a
d
b

10957

Description Nm lb. in. lb. ft.

Trim motor mounting screws 5.2 46
9. Install the reservoir tank over the electric motor and onto the pump assembly.
10. Install two 4 mm internal hex screws. Tighten the screws to the specified torque.
11. Secure the wire harness to the reservoir tank with a cable tie.
12. Fill the power trim system with Power Trim and Steering Fluid.
13. Install the reservoir tank fill plug.

a a- Reservoir tank
b- Fill plug
c- Cable tie
d- Reservoir tank mounting screws (4 mm internal hex)

10954

Description Nm lb. in. lb. ft.

Reservoir mounting screws 5.2 46

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system 92-858074K01
Fluid
14. Install the power trim assembly to the outboard. Refer to Power Trim Installation.

Page 5B-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
15. Trim the outboard through the entire trim and tilt range several times to remove any air from the system. Recheck the fluid
level.

Power Trim Cylinder

Power Trim Cylinder Disassembly
! CAUTION
Contamination can damage the hydraulic system or cause the system to malfunction. Failure of power trim or steering
components can result in injury or product damage. Ensure that the work area, shop tools and all components are clean and
lint free during reassembly.

NOTE: The power trim cylinder may be removed from the power trim assembly without removing the complete power trim
assembly from the outboard.
For complete removal of the power trim assembly refer to Power Trim Removal, preceding.

Power Trim Cylinder Removal while Installed on the Outboard

1. Tilt the outboard to the full up position and engage the tilt stop mechanism.

a - Tilt stop engaged

10509

2. Remove the trim cylinder rod pin retaining screw and washer.
3. Push trim cylinder rod pin through the bore from port side.

a - Tilt cylinder rod pin retaining screw and

washer
b - Tilt cylinder rod pin

a
b

10514

NOTE: Place an oil drip pan under the power trim assembly to catch fluid before removing the trim cylinder.
4. Use a hex wrench to remove the trim cylinder from the power trim assembly base by turning the cylinder counterclockwise.

Disassembly after Removal

IMPORTANT: Place the trim cylinder rod in a soft jaw vice. Scratching of the trim cylinder rod will result in external cylinder
leakage.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-31

Power Trim

1. Use a hex wrench to remove the trim cylinder from the power trim assembly base by turning the cylinder counterclockwise.

a - Trim cylinder
b - Power trim assembly base

18297

2. Place the trim cylinder rod in a soft jaw vice to remove the rod eye and jam nut.
3. Loosen the jam nut.
4. Remove the rod eye and jam nut.

a b c

d
18286

a- Outer cylinder tube

b- Trim cylinder rod
c- Jam nut
d- Rod eye

5. Remove paint, burrs, and sharp edges from the end of the trim rod.

Page 5B-32 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim

6. Remove the piston rod assembly and inner cylinder tube from the outer cylinder tube.

a
b

18278

a - Inner cylinder tube

b - Outer cylinder tube
c - Trim piston rod assembly

7. Remove the memory piston from the inner cylinder tube.

8. Remove the O‑ring and backup ring.

a a- Inner cylinder tube

b c b- Backup ring
c- O‑ring
d- Memory piston

18275

9. Remove the trim piston rod assembly from the inner cylinder tube.
10. Remove the O‑ring from the piston.

a b

18274

a - Inner cylinder tube

b - Trim piston O‑ring
c - Trim piston

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-33

Power Trim

11. Remove the O‑ring and seal from the outer trim cylinder tube.

a - Rod seal and O‑ring

b - Outer trim cylinder tube

18253

12. Remove the two O‑rings from the base of the power trim assembly base.

a a - O‑ring
b - Power trim assembly base

18251

Power Trim Cylinder Reassembly

NOTE: Replace all O‑rings and seals when reassembling the trim cylinder. Lubricate O‑rings and seals with clean Power Trim
and Steering Fluid or Automatic Transmission Fluid (ATF) (Dexron Type III) prior to installation.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim cylinder O-rings 92-858074K01
Fluid

Page 5B-34 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
1. Install a new O‑ring and seal in the outer trim cylinder tube.

a - Rod seal and O‑ring

b - Outer trim cylinder tube

18253

2. Install two new O‑rings in the base of the power trim assembly.

a a - O‑rings
b - Power trim assembly base

18251

3. Lightly lubricate the inside of the inner cylinder tube.

IMPORTANT: The trim piston assembly and the memory piston must be installed into the end of the inner cylinder tube
with the inside diameter chamfer.

a
a - Inner cylinder tube
b - Chamfer on inside
diameter

18288

4. Install a new lubricated O‑ring on the trim piston.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-35

Power Trim
5. Install the trim piston assembly into the inner cylinder tube.

a b

18290

a - Chamfered end of the inner cylinder tube

b - Trim piston O‑ring
c - Trim piston

6. Install a new lubricated O‑ring and backup seal on the memory piston.
7. Install the memory piston into the inner cylinder tube.

a a - Chamfered end of the inner

b c cylinder tube
b - Backup ring
c - O‑ring
d - Trim piston

18292

8. Install the piston rod assembly and inner cylinder tube into the outer cylinder tube.

a
b

18278

a - Inner cylinder tube

b - Outer cylinder tube
c - Trim piston rod assembly

IMPORTANT: Place the trim cylinder rod in a soft jawed vice. Scratching of the trim cylinder rod will result in external
cylinder leakage.
9. Place the trim cylinder rod in a soft jaw vice to install the rod eye and jam nut.

Page 5B-36 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Power Trim
10. Assemble the jam nut to the end of the threads on the trim rod.
11. Apply Loctite Threadlocker 271 to the cylinder rod threads.
12. Assemble the rod eye against the jam nut on the trim rod.
13. Tighten the jam nut against the rod eye. Tighten the jam nut to the specified torque.

a b c

d
18286

a- Outer cylinder tube

b- Trim cylinder rod
c- Jam nut
d- Rod eye

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Cylinder rod threads 92-809819

Description Nm lb. in. lb. ft.

Cylinder rod jam nut 35 25.8
14. Install the trim cylinder to the base of the power trim assembly. Tighten the trim cylinder to the specified torque.

a - Trim cylinder
b - Power trim assembly base

18297

Description Nm lb. in. lb. ft.

Trim cylinder 155 114
15. Fill the power trim reservoir with fluid.

Tube Ref No. Description Where Used Part No.

Power Trim and Steering
114 Power trim system reservoir 92-858074K01
Fluid

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5B-37

Power Trim
16. Install the power trim assembly to the outboard. Refer to Power Trim Installation, preceding.

Page 5B-38 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gas Assist Manual Trim/Tilt

Mid-Section
Section 5C - Gas Assist Manual Trim/Tilt
Table of Contents
Gas Assist Manual Trim/Tilt Components......................... 5C-2 Gas Assist Assembly Bushing Replacement..............5C-4
Gas Assist Manual Trim/Tilt System..................................5C-2 Installation.................................................................. 5C-5
Removal..................................................................... 5C-2

5
C

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5C-1

Gas Assist Manual Trim/Tilt

Gas Assist Manual Trim/Tilt Components

2
3
1

4
5
8
5
6

9
9

10
18624

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Button
2 1 Grip
3 1 Lever
4 1 Bolt 6 53
5 2 Washer
6 1 Nut 6 53
7 1 Gas assist trim cylinder
8 1 Upper pivot bushing
9 2 Bushing
10 1 Collar

Gas Assist Manual Trim/Tilt System

Removal
! WARNING
Escaping gas or oil under high pressure can cause serious injury. The manual trim unit contains high pressure oil and
nitrogen gas. Do not remove plugs from, disassemble, or apply heat to the part. Replace defective parts with new ones.

NOTE: The gas assist trim cylinder is not serviceable. If the cylinder is damaged, the unit must be replaced.
IMPORTANT: Clamp the engine securely to the transom before tilting to prevent it from rolling off the transom when turning the
engine.

Page 5C-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gas Assist Manual Trim/Tilt

1. Raise the outboard to the full up position and engage the tilt lock lever.

a - Tilt lock lever

18057

IMPORTANT: Block the engine to ensure that it does not tip over center when removing or installing the gas assist trim
cylinder.
2. Remove the retaining bolt and washer securing the upper pivot pin in the swivel bracket.
3. Remove the upper pivot pin.

a- Washer
b b- Retaining bolt
c c- Upper pivot pin
a d- Tilt lock lever

18058

4. Remove the snap ring and steel washer from the lower pivot pin.
5. Remove the lower pivot pin, collar, and gas assist trim cylinder.

a- Gas assist trim cylinder

b- Collar
c- Steel washer
d- Snap ring
e- Lower pivot pin
d

b c e
18061

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5C-3

Gas Assist Manual Trim/Tilt

6. Remove the four nylon bushings from the clamp brackets.

a b

18064

c c

a- Port clamp bracket

b- Starboard clamp bracket
c- Lower pivot bushings (4)
d- Anode

Gas Assist Assembly Bushing Replacement

! WARNING
Escaping gas or oil under high pressure can cause serious injury. The manual trim unit contains high pressure oil and
nitrogen gas. Do not remove plugs from, disassemble, or apply heat to the part. Replace defective parts with new ones.

1. Remove and replace the bushing in the upper pivot bore.

2. Remove and replace the two bushings in the cylinder rod eye.
3. Do not remove the cylinder end cap, internal hex plugs, or the plug from the gas assist trim cylinder.

a
c
d e d
b

18065

a- Rod eye bushing (2)

b- Upper pivot bushing
c- Cylinder end cap
d- Internal hex plug (2)
e- Plug

Page 5C-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gas Assist Manual Trim/Tilt

Installation
1. Install four bushings in the clamp brackets.

a b

18064

c c

a- Port clamp bracket

b- Starboard clamp bracket
c- Lower pivot bushings (4)
d- Anode

2. Insert the lower pivot pin through the port clamp bracket, collar, and gas assist cylinder rod eye.
3. Push the lower pivot pin through the starboard clamp bracket.

a- Gas assist trim cylinder

b- Port clamp bracket
c- Collar
d- Starboard clamp bracket
a e- Lower pivot pin

d
b
e
18068

4. Install a washer and snap ring.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 5C-5

Gas Assist Manual Trim/Tilt

NOTE: Ensure that the snap ring is secured in the groove.

a- Gas assist trim cylinder

b- Collar
c- Washer
d- Snap ring
e- Lower pivot pin
d

b c e
18061

5. Install the upper pivot pin in the swivel bracket and the gas assist cylinder.
6. Secure the upper pivot pin with a washer and retaining bolt. Tighten the bolt to specified torque.

a- Washer
b b- Retaining bolt
c c- Upper pivot pin
a d- Tilt lock lever

18058

Description Nm lb. in. lb. ft.

Upper pivot pin retaining bolt 6 53

Page 5C-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Lower Unit
Section 6A - Gear Housing
Table of Contents
Gearcase Specifications.................................................... 6A-2 Driveshaft Inspection................................................ 6A-27
Gear Housing (Driveshaft)................................................. 6A-6 Gear Housing Reassembly.............................................. 6A-28
Gear Housing (Propeller Shaft)..........................................6A-8 Pinion Bearing Installation........................................ 6A-28
General Service Recommendations................................ 6A-10 Forward Gear Bearing Installation............................ 6A-28
Bearings....................................................................6A-10 Bearing Carrier Reassembly.....................................6A-29
Shims........................................................................6A-10 Water Pump Base Reassembly................................6A-31
Seals.........................................................................6A-10 Propeller Shaft Reassembly..................................... 6A-31
Draining and Inspecting Gear Housing Lubricant............ 6A-10 Checking and Adjusting Pinion Gear Location......... 6A-32
Gear Housing Removal....................................................6A-11 Checking and Adjusting Forward Gear Backlash..... 6A-35
Gear Housing Disassembly............................................. 6A-13 Shift Shaft Installation............................................... 6A-37
Bearing Carrier Disassembly.................................... 6A-13 Water Pump Cover Reassembly.............................. 6A-38
Propeller Shaft Disassembly.....................................6A-17 Propeller Shaft and Bearing Carrier Installation....... 6A-40
Water Pump, Driveshaft and Shift Shaft Disassembly Anode Inspection and Installation.............................6A-41

6
.............................................................................. 6A-18 Gear Housing Installation......................................... 6A-42
Driveshaft Removal.................................................. 6A-24 Gearcase Lubricant Capacity................................... 6A-44
Forward Gear and Reverse Gear Inspection............6A-24 Gearcase Lubricant Recommendation..................... 6A-44
Driveshaft Pinion Bearing Inspection........................6A-26
Upper Driveshaft Bearing Inspection........................ 6A-26
Checking Lubricant Level and Refilling Gearcase.... 6A-44
Propeller Installation................................................. 6A-45
A

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-1

Gear Housing

Gearcase Specifications
Gearcase Specifications
Gear ratio 1.92:1
Gearcase capacity 350 ml (11.8 fl oz)
Gear lubricant type Premium Gear Lubricant or GL5 SAE 80‑90 Weight
Pinion teeth 12
Pinion height 0.60–0.64 mm (0.023–0.025 in.)
Clutch Dog type (forward ‑ neutral ‑ reverse)
Forward, reverse teeth 23
Forward gear backlash 0.33–0.54 mm (0.013–0.021 in.)
Water pressure at idle 50 kPa (7.2 psi)
Water pressure at WOT 95 kPa (13.7 psi)

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Extreme Grease Propeller shaft splines 8M0071842

7 Loctite 271 Threadlocker Pinion nut threads 92-809819

82 Premium Gear Lubricant Inside diameter and outside diameter of pinion bearing 92-858058K01

Shift shaft bushing O-ring

Seal lips
Bearing carrier O-ring
95 2-4-C with PTFE Seal lips and water pump base O-ring 92-802859A 1
Inside circumference of the water pump liner
Driveshaft splines
Propeller shaft splines

Special Tools
Torch Lamp 91‑63209

Heats surfaces to aid in the removal and installation of interference fit engine
components.

8776

Bearing Puller Assembly 91‑ 83165T

Removes bearings, races and bearing carriers

3610

Page 6A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Driveshaft Holding Tool 91‑853996 14

Holds the driveshaft while removing or installing the pinion gear nut.

17174

Slide Hammer 91‑34569A 1

Aids in the removal of various engine components. Use with puller jaws.
6761

Universal Puller Plate 91‑37241

Removes bearings from gears and the driveshaft.

8505

Bearing Installation Tool 91‑895195001

Aids in the installation of bearings into the gearcase.

12528

Pinion Nut Tool 91‑853996 12

Removes the pinion nut; aids in the installation of the driveshaft bearing.
17189

Bearing Mandrel Kit 91‑83166M

Aids in the removal and installation of bearings and bearing races.

3421

Pinion Height Tool 91‑895218

Aids in determining the pinion gear height.

17369

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-3

Gear Housing

Backlash Preload Tool 91‑895195004

Prevents forward gear movement when checking the forward gear backlash.

12520

Backlash Indicator Arm 91‑803133 12

Aids in determining the forward gear backlash; use with a dial indicator.
12512

Dial Indicator 91‑58222A1

Measures gear backlash and pinion gear location.

29495

Dial Indicator Adapter 91‑83155

Attaches the dial indicator to the gearcase when checking backlash.

2999

Page 6A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-5

Gear Housing

Gear Housing (Driveshaft)

21
20
34
19 33
15 18

16
14

13
12 32

35 38 17
36 31
36 1 30
37
3 2
4
29

28
27
7 26
5
25

24 22
36
23
8 39

10
4
5
3
11
6 16668

Page 6A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Gear Housing (Driveshaft)

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Gear housing
2 1 Needle bearing
3 2 Plug
4 2 Gasket
5 1 Water strainer set
6 1 Screw
7 1 Nut Drive tight
8 2 Water strainer
9 1 Screw Drive tight
10 1 Trim tab
11 1 Bolt (M6 x 20) 6 53
12 1 Nut 35 25
13 1 Gear (12 teeth)
14 1 Spring
15 1 Guide
16 1 Driveshaft
17 1 Key
18 1 Bearing assembly
19 AR Shim (0.1) (0.15) (0.3) (0.5)
20 1 Oil seal
21 1 O‑ring
22 1 Lower water pump housing
23 2 Dowel pin
24 1 Gasket
25 1 Water pump guide plate
26 1 Gasket
27 1 Impeller
28 1 Pump liner housing
29 1 Water pump housing
30 1 Lower seal
31 4 Bolt 6 53
32 1 Upper grommet
33 1 Water tube
34 1 Rubber hose (long shaft)
35 1 Bolt (long shaft)
36 5 Washer
37 1 Stud (short shaft)
38 1 Nut (short shaft) 19 168 14
39 4 Bolt 19 168 14

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-7

Gear Housing

Gear Housing (Propeller Shaft)

12 13 14

11
9
8

6
4 5
3

7 10 25

20 24
23
2

15
22
21
18
17
16 19

16667

Page 6A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Gear Housing (Propeller Shaft)

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Gear housing
2 1 Bearing assembly
3 AR Shim (0.1) (0.15)
4 1 Forward gear (23 teeth)
5 1 Cam follower
6 1 Ball
7 1 Holder
8 1 Spring
9 1 Clutch
10 1 Pin
11 1 Spring
12 1 Propeller shaft
13 1 Washer
14 1 Reverse gear (23 teeth)
15 1 Bearing carrier
16 1 O‑ring
17 1 Ball bearing
18 1 Needle bearing
19 1 Oil seal
20 2 Bolt 13 115
21 1 Thrust hub
22 1 Propeller
23 1 Washer
24 1 Prop nut 25 18
25 1 Cotter pin

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-9

Gear Housing

General Service Recommendations

There may be more than one way to disassemble or reassemble a particular part, therefore, it is recommended that the entire
procedure be read prior to repair.
IMPORTANT: Read the following before attempting any repairs.
In many cases, disassembly of a sub‑assembly may not be necessary, until cleaning and inspection reveals that disassembly is
required for replacement of one or more components.
Service procedure order in this section is a normal disassembly/reassembly sequence. It is suggested that the sequence be
followed without deviation to assure proper repairs. When performing partial repairs, follow the instructions to the point where
the desired component can be replaced, then proceed to reassembly and installation of that component in the reassembly part
of this section. Use the Table of Contents (on back of section divider) to find correct page number.
Threaded parts are right hand (RH), unless otherwise indicated.
When holding, pressing, or driving is required, use soft metal vise jaw protectors or wood for protection of parts. Use a suitable
mandrel (one that will contact only the bearing race) when pressing or driving bearings.
Whenever compressed air is used to dry a part, verify that no water is present in air line.

Bearings
Upon disassembly of gear housing, all bearings must be cleaned and inspected. Clean bearings with solvent and dry with
compressed air. Air should be directed at the bearing so that it passes through the bearing. Do not spin bearing with
compressed air, as this may cause bearing to score from lack of lubrication. After cleaning, lubricate bearings with Premium
Gear Lubricant. Do not lubricate tapered bearing cups until after inspection.
Inspect all bearings for roughness, catches, and bearing race side wear. Work inner bearing race in and out, while holding
outer race, to check for side wear.
When inspecting tapered bearings, determine condition of rollers and inner bearing race by inspecting bearing cup for pitting,
scoring, grooves, uneven wear, imbedded particles, and/or discoloration from overheating. Always replace tapered bearing and
race as a set.
Inspect gear housing for bearing races that have spun in their respective bores. If race has spun, gear housing must be
replaced.
Roller bearing condition is determined by inspecting the bearing surface of the shaft that the roller bearing supports. Check
shaft surface for pitting, scoring, grooves, imbedded particles, uneven wear, and/or discoloration from overheating. The shaft
and bearing must be replaced, if the conditions described are found.

Shims
Keep a record of all shim amounts and location during disassembly to aid in reassembly. Be sure to follow shimming
instructions during reassembly, as gears must be installed to correct depth and have the correct amount of backlash to avoid
noisy operation and premature gear failure.

Seals
As a normal procedure, all O‑rings and oil seals should be replaced without regard to appearance. To prevent leakage around
oil seals, apply Loctite 271 to outer diameter of all metal case oil seals. When using Loctite on seals or threads, surfaces must
be clean and dry. To ease installation, apply 2‑4‑C with PTFE on all O‑rings. To prevent wear, apply 2‑4‑C with PTFE on l.D. of
oil seals.

Draining and Inspecting Gear Housing Lubricant

! WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.

Page 6A-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
1. Position a clean drain pan under the gear housing and remove the fill and vent screws with gaskets from the gear housing.

a - Fill screw
b - Vent screw

a 16911

2. Inspect the gear lubricant for metal particles. Presence of a small amount of fine metal particles resembling powder
indicates normal wear. The presence of larger particles or a large quantity of fine particles indicates the need for gear
housing disassembly and for component inspection.
3. Note the color of gear lubricant. White or cream color indicates the presence of water in lubricant. Check the drain pan for
water separation from the lubricant. The presence of water in the gear lubricant indicates the need for disassembly, and
inspection of the oil seals, seal surfaces, O‑rings and gear housing components. Pressure check the gearcase prior to
disassembly.
NOTE: When draining the gearcase for the first time, lubricant may appear cream colored due to the mixing of assembly
lubricant and gear lubricant. This is not an indication of water intrusion. If, during subsequent draining of gearcase,
lubricant appears cream colored or milky, water may be present. The gearcase should be disassembled and all gaskets,
seals and O‑rings replaced. Inspect all components for water damage.
NOTE: Gear lubricant drained from a recently run gearcase will be a light chocolate brown in color due to agitation/
aeration. Oil which is stabilized will be a clear yellow brown in color.

Gear Housing Removal

! WARNING
Accidental starting can cause serious injury. Before removing or installing the gear housing, disconnect and isolate the spark
plug leads. Disable the ignition system by removing the keys from the ignition (if equipped) and engaging the lanyard stop
switch to prevent the engine from starting.

1. Remove the cotter pin from the propeller nut.

a - Cotter pin
b - Propeller nut

b
a

16913

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-11

Gear Housing
2. Remove the propeller nut, flat washer, propeller and forward thrust hub from the propeller shaft.

b c a- Propeller nut
e g
b- Cotter pin
a
c- Flat washer
d- Propeller
e- Forward thrust hub
f- Ring (faces toward gearcase)
g- Propeller shaft

f
d 16219

3. Use a suitable punch to remove the pin securing the upper shift shaft to the shift shaft coupler.
NOTE: On design 1 models, the upper and lower shift shafts are secured to the shift shaft coupler by pins. On design 2
models, the upper shift shaft is secured to the shift shaft coupler by a pin while the lower shift shaft is threaded into the
shift shaft coupler.

b
e

17114

a- Design 1 model shift shaft coupler

b- Upper shift shaft
c- Coupler
d- Upper shift shaft pin
e- Lower shift shaft pin

Page 6A-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

b
a
21060

a- Design 2 model shift shaft coupler

b- Lower shift shaft
c- Upper shift shaft pin
d- Coupler (with threaded lower shift shaft)
e- Upper shift shaft

4. Remove one nut and four bolts securing the gearcase to the driveshaft housing and remove the gearcase.

a - Bolts and washers (two each side)

b b - Nut and washer

a
21059

Gear Housing Disassembly

IMPORTANT: It is recommended that during complete disassembly of gear housing, all O‑rings and oil seals be replaced
regardless of their appearance.

Bearing Carrier Disassembly

1. Remove the two bolts securing the bearing carrier.

a - Bolts

16915

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-13

Gear Housing
2. Use screwdrivers at the indicated pry points to aid in the removal of the bearing carrier/propeller shaft assembly from the
gearcase.

a - Pry points

a 16916

3. Remove the bearing carrier and propeller shaft assembly from the gearcase.

a - Bearing carrier
b - Propeller shaft
a
b

16918

NOTE: The cam follower and ball bearing are free to slide out of the propeller shaft.

c a - Cam follower
b - Ball bearing
c - Bearing carrier assembly

b
a

16919

Page 6A-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
4. Remove the propeller shaft from the reverse gear/bearing carrier assembly.

c a - Propeller shaft
b b - Thrust washer
a c - Reverse gear/bearing
carrier assembly

16920

5. Replace the reverse gear if the gear teeth or clutch jaws are chipped or worn.

a a - Clutch jaws
b
b - Gear teeth

16921

6. If the reverse gear assembly must be replaced, remove the bearing carrier O‑ring to prevent heat damage. Use a Torch
Lamp to warm the bearing carrier where the reverse gear assembly is seated. Use a Bearing Puller Assembly to remove
the reverse gear from the reverse gear bearing.

a a - Torch Lamp
b - Reverse gear
c
c - Bearing Puller Assembly

16923

Torch Lamp 91‑63209

Bearing Puller Assembly 91‑ 83165T

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-15

Gear Housing
7. Inspect the reverse gear bearing for roughness, catches, pits, or discoloration from lack of lubricant. If the bearing must be
replaced, use a Torch Lamp to warm the bearing carrier assembly to aid in removal. Remove the O‑ring from the carrier to
prevent heat damage. Use a Bearing Puller Assembly to remove the bearing from the bearing carrier.

a a - Torch lamp
b - Reverse gear bearing
c
b c - Bearing puller assembly

16924

Bearing Puller Assembly 91‑ 83165T

Torch Lamp 91‑63209

NOTE: When using a screwdriver to remove carrier seals, do not scar the carrier seal surface. If the carrier seal surface is
damaged, replace the carrier.
8. Use a screwdriver to remove the oil seal from the bearing carrier.

b c a - Bearing carrier assembly

a b - Oil seal
c - Screwdriver

16925

9. Use a suitable mandrel to press the needle bearing out of the bearing carrier.

a - Bearing carrier
b b - Needle bearing (hidden)
c c - Mandrel

16928

Page 6A-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Propeller Shaft Disassembly

1. Inspect the cam follower and ball bearing for wear and replace if worn or damaged.
2. Remove the clutch pin retainer spring from the clutch.

b c a- Clutch
a
d b- Retainer spring
c- Ball bearing
d- Cam follower

16937

3. While pressing the cam follower against a hard surface, remove the clutch pin from the clutch/propeller shaft. Removal of
the clutch pin allows the clutch spring to discharge. Wear appropriate eye protection. Discard the clutch pin after removal.

! CAUTION
The spring‑loaded clutch pin can disengage from the clutch and propel through the air, causing possible eye injury. Always
wear protective eye equipment when disassembling the clutch assembly.

a - Cam follower
c b - Clutch pin
b
c - Punch

17048

4. Remove the spring and sliding clutch.

b e f g h a- Clutch
a c d
b- Ring (faces forward gear)
c- Clutch spring
d- Clutch pin holder
e- Clutch pin
16938 f- Clutch pin retainer spring
g- Ball bearing
h- Cam follower

5. Replace the clutch if the jaws are rounded or chipped. Rounded jaws may be caused by the following:
a. Improper shift cable or linkage adjustment
b. Engine idle speed too high while shifting
c. Shifting too slowly from neutral into forward or reverse

a a - Forward gear clutch jaws

b b - Reverse gear clutch jaws

16939

6. Inspect the needle bearing surface of the propeller shaft for pitting and wear. Replace the shaft and bearing carrier if wear
or pitting is present.
7. Replace the propeller shaft if any of the following exist:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-17

Gear Housing
a. Splines are twisted or worn
b. Oil seal surface is grooved
c. Shaft has a noticeable wobble or is bent more than 0.15 mm (0.006 in.).

a b c d b d

16962

a- Check shaft for wobble

b- Check for twisted splines
c- Check for seal surface grooves
d- Check for needle bearing surface pits or wear

Water Pump, Driveshaft and Shift Shaft Disassembly

1. Remove four screws from the water pump cover.

a a - Screws and washers

b - Water pump cover

21035

2. Remove the water pump cover from the driveshaft.

a - Water pump cover

21036

Page 6A-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
3. Remove the impeller and drive key from the driveshaft.

a - Impeller
b - Drive key

21037

4. It is recommended that the impeller be replaced whenever the gearcase is being serviced.
NOTE: If the impeller is not going to be replaced, do not install the impeller in reverse rotation to its original state as the
vanes have taken a set. The vanes will crack and break shortly after the outboard is returned to service.
5. Remove the water tube grommet from the pump cover. Inspect the grommet for wear or damage. Replace the grommet as
required. When installing the grommet into the pump cover, align the grommet tabs with the holes in the pump cover.
6. Inspect the pump cover for damage from excessive heat ‑ charring, blistering or discoloration. Replace the cover as
required.

a- Water pump cover

c b- Grommet
b
a c- Tabs
d- Holes

d
16969

7. Remove the water pump cover gasket.

a a - Water pump cover gasket

21038

IMPORTANT: The circular groove formed by the impeller sealing bead should be disregarded when inspecting the liner
and face plate. The depth of the groove will not affect the water pump output.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-19

Gear Housing
8. Remove the water pump face plate.

a a - Water pump face plate

21039

9. Inspect the water pump liner and face plate for grooves and/or rough surfaces.

a - Water pump cover

b - Water pump liner
a c - Face plate
c

16975
b
10. Replace the liner and/or face plate if the grooves (other than sealing grooves) are more than 0.762 mm (0.030 in.) deep.
11. Remove the base gasket.

a a - Base gasket

21040

Page 6A-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
12. Use the pry points to aid in the water pump base removal from the gear housing.

a - Pry points
a b - Water pump base
b

a
21042

13. Remove the water pump base seal with a screwdriver. Do not scar the water pump base seal surface with the screwdriver.
If the surface is damaged, replace the water pump base.

b a - Water pump base

b - Seal

16971

14. Remove the screw and washer securing the shift shaft assembly.

a a - Shift shaft assembly

b - Screw
c - Washer

b c

21043

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-21

Gear Housing
15. Inspect the shift cam for a groove or galling where the cam follower contacts. Replace the shift cam if worn. If the shift cam
is worn, inspect the cam follower for serviceability.

a - Shift cam

6607

NOTE: Before removing the worn shift cam, note the orientation of the shift cam face to the curve in the shift shaft to aid in
the proper installation of the new shift cam onto the shift shaft.

a a - Curve in shift shaft

b - Shift cam face

b 16978

16. To replace the shift cam, use a suitable punch to drive out the spring pin securing the shift cam to the shift shaft. Discard
the spring pin.

a - Punch
b - Spring pin

6613

Page 6A-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
17. Use a suitable punch to seat the new spring pin flush with the new shift cam surface.

a - Punch
b - Spring pin

6613

18. Unscrew the shift shaft coupler from the lower shift shaft.

b a - Spring pin
c
b - Shift shaft bushing
a c - Shift shaft coupler (unscrew)

21044

19. Remove the shift shaft bushing from the shift shaft.
20. Remove and replace the outside and inside O‑rings on the shift shaft bushing.
21. Apply 2‑4‑C with PTFE to the new O‑rings.

b a - Shift shaft bushing

a b - Inside O‑ring
c - Outside O‑ring

c 16988

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Shift shaft bushing O-ring 92-802859A 1
22. Install the shift shaft bushing onto the shift shaft.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-23

Gear Housing
23. Reinstall the shift shaft coupler onto the lower shift shaft.

b a - Spring pin
c
b - Shift shaft bushing
a c - Shift shaft coupler

21044

Driveshaft Removal
1. Use the Driveshaft Holding Tool to hold the driveshaft while removing the pinion nut.
2. Remove the driveshaft from the gearcase. Retain the shims located above the upper driveshaft bearing for reinstallation.

b a a - Driveshaft
b - Shims
c - Upper driveshaft bearing
c

16994

Driveshaft Holding Tool 91‑853996 14

3. Inspect the pinion gear teeth for breakage, rust, chipping or excessive wear.

a a - Pinion gear teeth

16996

4. If pinion gear teeth are damaged, inspect forward and reverse gears for damage and replace as required.
5. Remove the oil slinger tube from the gearcase.

a - Oil slinger tube

16995

Forward Gear and Reverse Gear Inspection

1. Inspect the forward gear and reverse gear teeth for breakage, rust, chipping, and excessive wear.
NOTE: Do not remove the forward gear race from the gearcase unless replacement is necessary.

Page 6A-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
2. If the forward gear bearing race must be replaced, remove the race using a Slide Hammer.

a - Forward gear race

a b b - Slide Hammer

16999

Slide Hammer 91‑34569A 1

3. Inspect the forward and reverse gear clutch jaws for wear. Rounded jaws indicate the following:
a. Improper shift cable or linkage adjustment
b. Engine idle speed too high
c. Shifting too slowly

b a - Forward gear teeth

a b - Propeller shaft bushing
c - Clutch jaws

c
17007

4. Inspect the forward gear tapered roller bearing for rust, roughness, or excessive wear.
5. If the bearing is in serviceable condition, do not remove the bearing from the gear. The removal process may damage the
bearing.
6. If the forward gear tapered bearing must be replaced, use a suitable mandrel, Universal Puller Plate, and press to remove
the bearing from the forward gear.
NOTE: Replace the forward gear bearing race located in the gearcase if the forward gear tapered bearing is replaced.

a- Universal Puller Plate

c b- Tapered bearing
c- Mandrel
b d- Forward gear
a

d
17008

Universal Puller Plate 91‑37241

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-25

Gear Housing
7. Inspect the area of the propeller shaft where the forward gear bushing contacts to determine the condition of the forward
gear bushing. Replace the propeller shaft and forward gear assembly if the surface is discolored from lack of lubricant,
pitted, or worn.

a a - Forward gear bushing surface

17009

Driveshaft Pinion Bearing Inspection

IMPORTANT: Do not remove the lower driveshaft pinion bearing from the gearcase unless replacement is necessary. The
removal process may damage the bearing.
1. Inspect the pinion bearing surface on the driveshaft. Replace the driveshaft and the pinion bearing if it is pitted, grooved,
scored, worn unevenly, discolored from overheating, or has embedded particles.

a b a - Pinion bearing surface

b - Oil slinger spring

17010

2. Use the Bearing Installation Tool to remove the pinion bearing.

a a- Puller shaft
c b- Nut (part of Bearing Installation Tool)
b c- Washer (part of Bearing Installation Tool)
d d- Flange (part of Bearing Installation Tool)
e- Guide
f- Pinion bearing
g- Retainer (part of Bearing Installation Tool)

16251

Bearing Installation Tool 91‑895195001

IMPORTANT: The gear housing must be replaced if the forward gear tapered bearing race, upper driveshaft bearing, or pinion
bearing appear to be spinning in their respective bores.

Upper Driveshaft Bearing Inspection

IMPORTANT: Do not remove the upper driveshaft tapered bearing from the driveshaft unless replacement is necessary. The
removal process may damage the bearing.
1. Inspect the upper driveshaft tapered bearing for rust, roughness, or excessive wear.

Page 6A-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
2. If the bearing is not in serviceable condition, use a Universal Puller Plate and press to remove the bearing from the
driveshaft.

a - Universal Puller Plate

b - Upper driveshaft bearing

b
a

17019

Universal Puller Plate 91‑37241

3. To install the new bearing, place the bearing onto the driveshaft.
4. Partially thread the old pinion nut onto the driveshaft.
5. Place the driveshaft assembly into a press.
6. Slide the driveshaft through the Pinion Nut Tool so that pressure is applied to the inner race of the bearing during
installation.
7. Apply pressure to the old pinion nut to push the driveshaft through the new bearing until the bearing seats against the
ledge.

a- Universal Puller Plate

b- Pinion Nut Tool
c- Upper driveshaft bearing
d- Ledge
e
e- Old pinion nut

d
c
b
a

17020

Pinion Nut Tool 91‑853996 12

Universal Puller Plate 91‑37241

Driveshaft Inspection
1. Inspect the splines at both ends of the driveshaft for a worn or twisted condition. Replace the driveshaft if either condition
exists.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-27

Gear Housing
2. Inspect the driveshaft for grooves where the water pump base oil seals contact the shaft. Replace the driveshaft if grooves
are found.

a a - Water pump oil seal surface

17022

Gear Housing Reassembly

Pinion Bearing Installation
1. Install the Bearing Installation Tool into the driveshaft bore.
2. Apply Premium Gear Lubricant to the inside diameter and outside diameter of a new pinion bearing and install the pinion
bearing (numbers/letters face up) onto the Bearing Installation Tool shaft.
3. Use the appropriate retainer from the Bearing Installation Tool kit to hold the pinion bearing onto the tool shaft.
4. With the flange of the installation tool against the gearcase surface, turn the nut on the tool shaft until the shaft is drawn up
against the flange. The pinion bearing will then be seated at the proper height. Remove the retainer and the Bearing
Installation Tool assembly from the driveshaft bore.

a a- Puller shaft
c b- Nut (part of Bearing Installation Tool)
b
d c- Washer (part of Bearing Installation Tool)
d- Flange (part of Bearing Installation Tool)
e- Collar
f- Guide
e g- Pinion bearing
h- Retainer (part of Bearing Installation Tool)

f
g

16249

Tube Ref No. Description Where Used Part No.

82 Premium Gear Lubricant Inside diameter and outside diameter of pinion bearing 92-858058K01

Bearing Installation Tool 91‑895195001

Forward Gear Bearing Installation

1. Place forward gear shim onto forward gear.

Page 6A-28 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
2. Use a suitable mandrel which contacts only the inner diameter of the forward gear bearing to press the bearing onto the
forward gear.

a- Mandrel
a b- Forward gear bearing
c- Forward gear
b
d- Forward gear shim (hidden)
c

17033

3. Secure the gearcase in a holding fixture.

4. Install the forward gear bearing race into the gearcase.
5. Use an appropriate mandrel from the Bearing Mandrel Kit to seat the race into gearcase.

a a - Gearcase holding fixture

b - Mandrel

17034

Bearing Mandrel Kit 91‑83166M

Bearing Carrier Reassembly

1. Apply 2‑4‑C with PTFE to the seal lips.
2. Install the seal with the seal face up.
3. Use a suitable mandrel from the Bearing Mandrel Kit to press the seal into the carrier until seated.

a a - Mandrel
b
b - Seal (install face up)

17035

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-29

Gear Housing

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Seal lips 92-802859A 1

Bearing Mandrel Kit 91‑83166M

4. When installing the new needle bearing, press on the letter side of the bearing until the bearing is just below the ledge.

b a - Letter side of bearing

b - Ledge
a

17036

5. Use a suitable mandrel which contacts the inner diameter of the bearing to press the new bearing onto the reverse gear.

a - Mandrel
a b - Reverse gear bearing
c - Reverse gear
b
c

17038

IMPORTANT: Do not install the bearing carrier O‑ring if a Torch Lamp is to be used on the carrier. The O‑ring may be
damaged by the heat.
6. Use a suitable mandrel from the Bearing Mandrel Kit to press the reverse gear/bearing assembly into the bearing carrier
until the bearing is seated.

a a- Mandrel
b b- Reverse gear
c- Bearing
c d- Bearing carrier

17039

Bearing Mandrel Kit 91‑83166M

Page 6A-30 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
7. Apply 2‑4‑C with PTFE to the new bearing carrier O‑ring and install the O‑ring onto the bearing carrier.

a - O‑ring
a

17041

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Bearing carrier O-ring 92-802859A 1

Water Pump Base Reassembly

1. Use a suitable mandrel to press on the face of the seal until the seal is seated in the water pump base.
2. Apply 2‑4‑C with PTFE to the seal lips.
3. Install a new O‑ring on the water pump base. Apply 2‑4‑C with PTFE to the new O‑ring.

a- Mandrel
a b- Seal
c- O‑ring
b d- Water pump base

c
d

17042

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Seal lips and water pump base O-ring 92-802859A 1

Propeller Shaft Reassembly

1. Slide the clutch onto the propeller shaft with the ring on the clutch facing toward the forward gear. Ensure that the hole in
the clutch aligns with the slot in the propeller shaft.

a b a- Clutch
b- Ring faces toward forward gear
c- Cross pin hole
d- Slot

d c 17044

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-31

Gear Housing
2. Install the clutch spring, clutch pin holder, ball bearing, and cam follower into the shaft.

b e f g h a- Clutch
a c d
b- Ring (faces toward forward gear)
c- Clutch spring
d- Clutch pin holder
e- Clutch pin
16938 f- Clutch pin retainer spring
g- Ball bearing
h- Cam follower

3. Compress the cam follower against a hard surface while aligning the clutch cross pin hole with the hole in the clutch pin
holder.
4. Press the clutch cross pin through the clutch and clutch pin holder until flush with the surface.

a - Cam follower (press against hard surface)

b - Clutch cross pin (press in until flush)

17376

NOTE: It is recommended that the cross pin retainer spring not be reused if it shows signs of wear or damage.
5. Install the retainer spring onto the clutch. Do not overlap the retainer spring coils.

b a a - Clutch retainer spring

b - Clutch cross pin

17051

6. Install the thrust washer onto the propeller shaft.

7. Install the propeller shaft assembly into the bearing carrier assembly.

c a - Propeller shaft assembly

b b - Thrust washer
a c - Bearing carrier assembly

16920

Checking and Adjusting Pinion Gear Location

NOTE: Pinion gear height must be set prior to checking forward gear backlash.

Page 6A-32 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
1. Install the driveshaft bearing oil slinger into the gearcase.

a - Slinger

16995

2. With shims retained on top of driveshaft bearing, install the driveshaft assembly through the pinion bearing.

b a a - Driveshaft
b - Shims (retained)
c - Upper driveshaft bearing
c

16994

IMPORTANT: Install the pinion nut with the step side of the nut against the pinion gear.

a b a - Pinion gear
b - Pinion nut
c - Step side (install toward pinion gear)

c 17053

3. Lift the driveshaft slightly and install the pinion gear. Thread the pinion nut onto driveshaft with the step side of the nut
towards the pinion gear.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-33

Gear Housing
4. Using the Driveshaft Holding Tool and the Pinion Nut Tool, torque the pinion nut to specification.

a a - Driveshaft Holding Tool

b - Pinion nut (hidden)
c - Pinion Nut Tool

16406

Driveshaft Holding Tool 91‑853996 14

Pinion Nut Tool 91‑853996 12

Description Nm lb. in. lb. ft.

Pinion nut 35 25
5. Install the water pump base and pump cover onto the gearcase. Torque the pump cover screws to specification.
6. Install the Pinion Height Tool into the forward gear bearing race. The flat side of the tool faces up when installed in the
bearing race.
NOTE: Take the following measurements at three locations, rotating the driveshaft 120 degrees between each reading.
Rotate the driveshaft in a clockwise direction.

Page 6A-34 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
7. Pull up on the driveshaft and insert the thickest feeler gauge that fits snugly between one tooth of the pinion gear and the
high point of the Pinion Height Tool.

a a- Driveshaft (pull up)

c b- Water pump cover
c- Water pump cover screws
b d- Water pump base
d e- Shims
f- Upper driveshaft bearing
e g- Oil slinger
h- Pinion gear
f i- Flat side of Pinion Height Tool faces up
g j- Forward gear bearing race
k- Measure between bottom of pinion tooth and high
point of tool
m h l - Pinion Height Tool
m - Feeler gauge
i

k
j
l

17368

Description Nm lb. in. lb. ft.

Water pump cover screws 6 53

Pinion Height Tool 91‑895218

8. Rotate the driveshaft 120 degrees in a clockwise direction and take another reading.
9. Repeat this process until three readings have been taken.
10. Add the three readings together and divide the sum by three to get the average pinion height.

Pinion Height
Average pinion height 0.60–0.64 mm (0.023–0.025 in.)
11. If the average pinion height is not correct, remove the water pump cover and base. Add to or subtract from the shims
located on top of the upper driveshaft bearing to obtain the proper average pinion gear height. Reinstall the pump cover
and base. Torque the pump cover screws to specification. While pulling up on the driveshaft, repeat the measurement
process at three different locations 120 degrees apart.
12. After the correct pinion gear height is achieved, remove the pinion nut, pinion gear, water pump cover, and water pump
base.

Checking and Adjusting Forward Gear Backlash

NOTE: Forward gear shims are located between the forward gear and the forward gear bearing. Adding shims reduces
backlash, removing shims increases backlash.
1. Lift the driveshaft assembly enough to install the forward gear bearing assembly into the forward gear race.
2. Secure the pinion gear to the driveshaft with the pinion nut. Torque the nut to specification.
3. Install the water pump cover and water pump base onto the gearcase. Secure the pump cover and base with the pump
cover screws. Torque the screws to specification.
4. Install the forward gear Backlash Preload Tool into the gearcase.
5. Use a screwdriver to turn the tool shaft to apply light pressure against the forward gear assembly to prevent forward gear
rotation.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-35

Gear Housing
6. Attach the backlash indicator arm to the driveshaft.

a - Backlash Indicator
Arm
a
b - Water pump cover
b c - Water pump base
d - Shims
c e - Driveshaft bearing
f - Forward gear
d assembly
g - Collar (part of
e Backlash Preload
Tool Kit ‑ O‑ring is
located under collar)
k h - O‑ring
i - Tapered washers
m j - Backlash Preload
f j Tool
k - Bearing carrier
i attaching screws
h l - Plate (part of
l g Backlash Preload
Tool Kit)
j m - Jam nuts
k

16394

Description Nm lb. in. lb. ft.

Pinion nut 35 25
Water pump cover screws 6 53

Backlash Preload Tool 91‑895195004

Backlash Indicator Arm 91‑803133 12
Driveshaft Holding Tool 91‑853996 14
Pinion Nut Tool 91‑853996 12
7. Attach the dial indicator to the threaded rod (obtain locally) and align the dial indicator shaft with the V notch on the
indicator arm.
8. Lift up on the driveshaft and lightly rotate the driveshaft back and forth. Check the dial indicator for the amount of backlash.
Adding shims between the forward gear and the forward gear bearing reduces backlash. Removing shims increases
backlash.
9. After the correct forward gear backlash has been obtained, remove the pinion gear nut. Remove any oil from the pinion nut
threads. Apply Loctite 271 Threadlocker to the pinion nut threads and reinstall the pinion gear and pinion nut. Torque the
pinion nut to specification.

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Pinion nut threads 92-809819

Description Nm lb. in. lb. ft.

Pinion nut 35 25
10. Remove the Backlash Indicator Arm from the driveshaft.
11. Remove the Dial Indicator Assembly.

Page 6A-36 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
12. Remove the water pump cover and screws.

f a- Water pump base

e b- Water pump cover
c- Screws
g d- V notch
d e- Backlash Indicator Arm
f- Adapter
c g- Dial Indicator
h- Threaded rod (obtain locally)
i- Nuts and washers (obtain locally)
b

i
a
17063

Forward Gear
Backlash 0.33–0.54 mm (0.013–0.021 in.)

Driveshaft Holding Tool 91‑853996 14

Pinion Nut Tool 91‑853996 12
Dial Indicator 91‑58222A1
Dial Indicator Adapter 91‑83155
Backlash Indicator Arm 91‑803133 12

NOTE: The values in the following table represent possible dial indicator readings and the resultant shim changes required
to achieve the recommended backlash. (+) requires a shim value to be added; (‑) requires a shim value to be subtracted.

Gauge Reading Shim Adjustment

0.00–0.05 mm (0.00–0.002 in.) –0.15 mm (–0.006 in.)
0.06–0.20 mm (0.002–0.008 in.) –0.10 mm (–0.004 in.)
0.21–0.32 mm (0.008–0.012 in.) –0.05 mm (–0.002 in.)
0.33–0.54 mm (0.013–0.021 in.) 0.00 mm (0.000 in.)
0.55–0.65 mm (0.022–0.026 in.) +0.05 mm (+0.002 in.)
0.66–0.80 mm (0.026–0.031 in.) +0.10 mm (+0.004 in.)
0.81–0.95 mm (0.032–0.037 in.) +0.15 mm (+0.006 in.)
0.96–1.11 mm (0.038–0.044 in.) +0.20 mm (+0.008 in.)
1.12–1.30 mm (0.044–0.051 in.) +0.25 mm (+0.010 in.)
1.31–1.45 mm (0.052–0.057 in.) +0.30 mm (+0.012 in.)
1.46–1.60 mm (0.057–0.063 in.) +0.35 mm (+0.014 in.)
1.61–1.75 mm (0.063–0.069 in.) +0.40 mm (+0.016 in.)
1.76–1.90 mm (0.069–0.075 in.) +0.45 mm (+0.018 in.)
1.91–2.05 mm mm (0.075–0.081 in.) +0.50 mm (+0.020 in.)
2.06–2.25 mm (0.081–0.089 in.) +0.55 mm (+0.022 in.)

Shift Shaft Installation

1. Install the shift shaft with the bushing into the gearcase.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-37

Gear Housing
2. Secure the shift shaft bushing with a screw and washer. Torque the screw to specification.

a a - Shift shaft assembly

b - Screw
c - Washer

b c

21043

Description Nm lb. in. lb. ft.

Screw 6 53

Water Pump Cover Reassembly

1. Align the locating tab on top of the water pump liner with the slot in the water pump cover and insert the liner into the pump
cover.

a - Slot
a b - Water pump liner tab
b

17095

2. Install a new base plate gasket.

a a - Base plate gasket

21040

Page 6A-38 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
3. Install a new face plate.

a a - Face plate

21039

4. Install a new water pump cover gasket.

a a - Water pump cover gasket

21038

5. Install the drive key.

IMPORTANT: It is recommended that the impeller be replaced regardless of appearance. If the impeller must be reused, it
must be installed in the direction of original rotation. Installing the impeller with the vanes reversed from their previous set
will result in vane breakage shortly after the unit is returned to service.
6. Install a new impeller and align with the drive key.

a - Impeller
b - Drive key

21037

7. Lubricate the inside circumference of the water pump liner with 2‑4‑C with PTFE.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-39

Gear Housing
8. Install the pump cover on the driveshaft. Push down on the cover, rotate the driveshaft clockwise, and install the pump
cover over the impeller.

a - Water pump cover

21036

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Inside circumference of the water pump liner 92-802859A 1
9. Secure the cover with screws and washers. Tighten the screws to the specified torque.

a a - Screws and washers

b - Water pump cover

21035

Description Nm lb. in. lb. ft.

Water pump cover screws 6 53

Propeller Shaft and Bearing Carrier Installation

1. Apply 2‑4‑C with PTFE to the bearing carrier O‑ring.
2. Install the bearing carrier/propeller shaft assembly into the gearcase.

Page 6A-40 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
3. Rotate the driveshaft while seating the bearing carrier assembly into the gear housing to ensure pinion gear and reverse
gear are in mesh.

a - Bearing carrier assembly

b - Propeller shaft
a
b

16918

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Bearing carrier O-ring 92-802859A 1
4. Secure the bearing carrier with two screws. Torque the screws to specification.

a - Screws

16915

Description Nm lb. in. lb. ft.

Bearing carrier assembly screws 13 115 9

Anode Inspection and Installation

1. The gearcase has an auxiliary water pickup/strainer located under the anti‑ventilation plate. This auxiliary water pickup/
strainer is designed to provide water to the engine should the primary water pickup/strainers on the side of the gearcase
become partially blocked with debris. The auxilary pickup should be inspected periodically for debris. Debris can be
removed from the strainer and the adjacent cavity by removing the attaching screw.
2. The anode/trim tab located under the anti‑ventilation plate serves two purposes:
a. As an anode it helps protect the outboard against galvanic corrosion by sacrificing its metal to be slowly eroded
instead of the outboard metals. It requires periodic inspection especially in salt water which will accelerate the
erosion. Replace the anode before it is completely eroded. Never paint or apply a protective coating on the anode as
this will reduce the effectiveness of the anode.
b. As a trim tab, it helps balance the steering torque so that the steering wheel or tiller handle will move with equal effort
in either direction. As the anode/trim tab erodes, its ability to balance steering torque will be reduced. To adjust the
anode/trim tab, loosen the screw which secures the anode/trim tab and turn the trailing edge of the tab in the direction
in which the boat turns more easily. For example ‑ if the boat turns more easily to the left, turn the trailing edge of the
tab to the left. If the boat turns more easily to the right, turn the trailing edge of the tab to the right.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-41

Gear Housing
3. Secure anode/trim tab to the gear housing with the screw. Torque the screw to specification.

a a- Anode
b b- Anode Screw
c- Water pickup/strainer
d- Water pickup/strainer screw

d
c

17096

Description Nm lb. in. lb. ft.

Anode/trim tab attaching screw 6 53
Water pickup/strainer screw Drive tight

Gear Housing Installation

! WARNING
Accidental starting can cause serious injury. Before removing or installing the gear housing, disconnect and isolate the spark
plug leads. Disable the ignition system by removing the keys from the ignition (if equipped) and engaging the lanyard stop
switch to prevent the engine from starting.

1. Remove and isolate the spark plug leads from the spark plugs.
2. Tilt the outboard to the full up position.
3. Place the shift handle (tiller models) or shift lever (remote control models) into forward.
4. Place the gear housing into forward gear by lifting up on the lower shift shaft until the shift shaft stops its upward
movement. Lightly push down on the lower shift shaft until resistance is felt.
5. Coat the splines of the driveshaft with 2‑4‑C with PTFE.

NOTICE
Installing the gear housing to the powerhead without adequately cleaning the top of the driveshaft can result in severe
product damage. Any lubricant trapped in the space between the driveshaft and the crankshaft prevent the two from properly
engaging. Always clean the top of the driveshaft before installing the gear housing.
6. Guide the gear housing into the driveshaft housing aligning the water tube in the driveshaft housing with the water tube
grommet in the water pump cover.
7. Install the gearcase retaining screws, washers and nut. Tighten the screws, and the nut to the specified torque.

a - Screws and washers (two each side)

b b - Nut and washer

a
21059

Page 6A-42 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing

Description Nm lb. in. lb. ft.

Gearcase retaining screws 19 168
Nut 19 168

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Driveshaft splines 92-802859A 1

NOTE: On long shaft models, thread the shift shaft coupler down (clockwise) on the lower shift shaft until the coupler
stops. Turn the coupler up (counterclockwise) five turns from a lightly seated position (approximately 5.8 mm [0.230 in.]
from the start of the taper on the lower shift). Adjust the coupler up or down slightly to align the shift shaft coupler with the
upper shift shaft.

a - Coupler lightly seated

b - Coupler five threads up 5.8 mm [0.230 in.]
a
b

22648
NOTE: On short shaft models, thread the shift shaft coupler down (clockwise) on the lower shift shaft until the coupler
stops. Turn the coupler up (counterclockwise) two and one half turns from a lightly seated position (approximately 3.7 mm
[0.15 in.] from the start of the taper on the lower shift). Adjust the coupler up or down slightly to align the shift shaft coupler
with the upper shift shaft.

a - Coupler lightly seated

b - Coupler three threads up 3.7 mm (0.15 in.)
a

22649

NOTE: On tiller handle models, the reverse lock link must be pushed up to prevent any tension on the upper shift shaft
while adjusting the shift shaft coupler to align the upper shift shaft with the lower shift shaft.

a a - Reverse lock link

(push up)
b - Upper shift shaft
c - Lower shift shaft
d d - Shift shaft coupler

b
c

22535

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-43

Gear Housing
8. Push up on the lower shift shaft and coupler assembly while adjusting the shift shaft coupler to align the upper shift shaft
hole in the coupler with the upper shift shaft.
9. Insert the upper shift shaft into the shift shaft coupler.
10. Secure the upper shift shaft in the coupler with a new spring pin using a suitable punch or press in with a pair of pliers.

b
a
21060

a- Exploded view
b- Lower shift shaft
c- Spring pin
d- Shift shaft coupler
e- Upper shift shaft

11. Lower the outboard to the normal operating position.

12. Check the shift operation as follows:
• Place the shift lever in forward. The gear housing should ratchet when the propeller shaft is turned clockwise and
resistance should be felt when the propeller is turned counterclockwise.
• Place the shift lever in neutral. Resistance should not be felt when the propeller shaft is rotated in either direction.
• Place the shift lever in reverse. Resistance should be felt when the propeller shaft is rotated in either direction.
• If the shift operation is not as described, recheck the coupler installation procedure. If the coupler is adjusted
correctly, the gearcase may not be properly reassembled. Internal parts may be excessively worn and must be
replaced before the outboard is returned to service.

Gearcase Lubricant Capacity

Gearcase lubricant capacity is approximately 350 ml (11.8 fl oz).

Gearcase Lubricant Recommendation

Mercury or Quicksilver Premium or High Performance Gear Lubricant.

Checking Lubricant Level and Refilling Gearcase

1. Place outboard in a vertical operating position.
2. Remove vent plug.

Page 6A-44 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Gear Housing
3. Remove drain plug. Place lubricant tube into the fill hole and add lubricant until it appears at the vent hole.

a a - Vent plug and sealing washer

b - Drain plug and sealing washer

b
9836

IMPORTANT: Replace sealing washers if damaged.

4. Stop adding lubricant. Install the vent plug and sealing washer before removing the lubricant tube.
5. Remove lubricant tube and reinstall cleaned fill/drain plug and sealing washer.

Propeller Installation
! WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.

1. To aid in the future removal of the propeller, liberally apply to the propeller shaft splines with one of the following Mercury/
Quicksilver products:

Tube Ref No. Description Where Used Part No.

Extreme Grease Propeller shaft splines 8M0071842

95 2-4-C with PTFE Propeller shaft splines 92-802859A 1

2. Install the front thrust hub, propeller, rear thrust washer, and the propeller nut onto the shaft.
IMPORTANT: The ring on the front thrust hub must face towards the gearcase in order for the hub to be fully installed on
the propeller shaft.
3. Place a block of wood between the gearcase and the propeller to prevent rotation and tighten the propeller nut. Torque the
propeller nut to specification and secure the nut to the shaft with a cotter pin.
NOTE: If the propeller nut does not align with the propeller shaft hole after tightening to the specified torque, then tighten
the nut farther to align it with the hole.

b c a- Nut
e g
b- Cotter key
a
c- Rear thrust washer
d- Propeller
e- Front thrust hub
f- Ring (faces toward gearcase)
g- Propeller shaft

f
d 16219

Description Nm lb. in. lb. ft.

Propeller nut 25 18

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 6A-45

Gear Housing

Notes:

Page 6A-46 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

Attachments
Section 7A - Throttle/Shift Linkage
Table of Contents
Throttle and Steering Linkage Components...................... 7A-4 Throttle Only Removal and Disassembly....................7A-9
Shift and Cam Rod Components....................................... 7A-6 Throttle Only Reassembly and Installation............... 7A-11
Tiller Handle Models.......................................................... 7A-8 Remote Control Models................................................... 7A-15
Throttle Only Operation.............................................. 7A-8 Shift Control Removal and Disassembly.................. 7A-15
Neutral Safety Start Switch.........................................7A-8 Shift Control Assembly and Installation.................... 7A-17

7
A

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-1

Throttle/Shift Linkage

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
Shift detent, throttle only gears
Throttle only drive and driven gears
95 2-4-C with PTFE 92-802859A 1
Shift detent
Shift lever shaft

Special Tools
DMT 2004 Digital Multimeter 91‑892647A01

Measures RPM on spark ignition (SI) engines, ohms, amperes, AC and DC

V Hz
H z TEMP
mA
A
voltages; records maximums and minimums simultaneously, and accurately
reads in high RFI environments.
mV IG
OFF IP

TEMP

A mA COM V Hz

4516

Page 7A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-3

Throttle/Shift Linkage

Throttle and Steering Linkage Components

7
5
6
3

8 9
2 4
3
11
10
12
17 13
18 22
12 23

24 18 16 15
17
15 18
17
18 14
17

21 21
19 19
19 20
37 14 20
19

25
32
28 33 36
30 34
29
33 31
26 27

33
35 32 16670

Page 7A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

Throttle and Steering Linkage Components

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Throttle arm (handle)
2 1 Bolt (handle) 6 53
3 2 Washer (handle)
4 1 Collar (handle)
5 2 Washer (handle)
6 2 Cotter pin (handle)
7 2 Rod end (handle)
8 2 Nut (handle)
9 1 Throttle rod (handle)
10 1 Throttle rod (handle)
11 1 Throttle link rod (remote control)
12 2 Nut (remote control)
13 1 Ball socket (remote control)
14 2 Shift and throttle arm bracket (remote control)
15 4 Bolt (M6 x 16) (remote control) 6 53
16 1 Throttle arm (remote control)
17 4 Washer (remote control)
18 4 Cotter pin (remote control)
19 2 Washer (remote control)
20 2 Collar (remote control)
21 2 Bolt (remote control) 6 53
22 1 Shift link rod (remote control)
23 1 Cable joint (remote control)
24 1 Shift arm (remote control)
25 1 Grommet (remote control)
26 1 Plate (remote control)
27 2 Bolt (remote control)
28 2 Washer (remote control)
29 1 Clamp (remote control)
30 1 Bolt (M6 x 16) (remote control) 6 53
31 1 Drag link (remote control)
32 2 Nut (remote control) 27.1 20
33 3 Washer (remote control)
34 1 Spacer (remote control)
35 1 Screw (remote control)
36 1 Cap (remote control)
37 1 Harness clamp

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Throttle/Shift Linkage

Shift and Cam Rod Components

19
13 14
15
18

19
22
33
95
32 31
30 20
29
17
28 21

26
16
34
35 25
24 23
36
9 12
95

10 11
27
7 6
8 5
5
38
4

41
42
3

40 2

37

39 3
1
16669

Page 7A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

Shift and Cam Rod Components

Torque
Ref. No. Qty. Description Nm lb. In. lb. ft.
1 1 Clutch cam (component of complete gear housing)
2 1 Cam rod (component of complete gear housing)
3 2 Pin (component of complete gear housing)
4 1 Bushing (component of complete gear housing)
5 2 O‑ring (component of complete gear housing)
6 1 O‑ring (component of complete gear housing)
7 1 Bolt (component of complete gear housing) 6 53
8 1 Washer (component of complete gear housing)
9 1 Upper shift shaft
10 1 Shift rod joint
11 2 Dowel pin
12 1 Grommet (handle)
13 1 Shift lever shaft bracket
14 1 Bolt 6 53
15 1 Shift detent spring (handle)
16 1 Shift detent (handle)
17 2 Bolt 6 53
18 1 Gear plate (handle)
19 6 Bolt (handle) 6 53
20 1 Spring (handle)
21 1 Shift lever shaft (handle)
22 1 Pin (handle)
23 1 Nut (handle) 6 53
24 1 Washer (handle)
25 1 Bushing (handle)
26 1 Drive gear (handle)
27 1 Driven gear (handle)
28 1 Gear plate (starboard) (handle)
29 1 Throttle pulley (handle)
30 1 Washer (handle)
31 1 Throttle opener (handle)
32 1 Bushing (handle)
33 1 Bolt (handle) 6 53
34 1 Grommet (handle)
35 1 Button (handle)
36 1 Actuator (handle)
37 1 Bracket (starboard) (remote control)
38 2 Bolt (remote control) 6 53
39 1 Shift lever shaft (remote control)
40 1 Shift arm (remote control)
41 1 Bolt (remote control) 6 53
42 1 Washer (remote control)

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Shift detent, throttle only gears 92-802859A 1

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Throttle/Shift Linkage

Tiller Handle Models

Throttle Only Operation
1. Rotate throttle handle to neutral.
2. Depress the throttle only button while rotating throttle handle grip to full forward. Release throttle only button.
NOTE: Engine throttle linkage should increase throttle opening. Gearcase should remain in neutral.
3. Rotate throttle handle grip back to neutral. The handle grip should stop in the neutral detent position.
4. Depress the throttle only button while rotating throttle handle grip to full reverse. Release throttle only button.
NOTE: Engine throttle linkage should increase throttle opening. Gearcase should remain in neutral.
5. Rotate throttle handle grip back to neutral. The handle grip should stop in the neutral detent position.

Neutral Safety Start Switch

Continuity Test
1. Remove the electrical bracket cover.
2. Disconnect both green neutral start safety switch bullet leads.

a - Green neutral start safety switch bullet leads (2)

18955

3. Test the neutral start safety switch for continuity in forward, neutral, and reverse gear.

DMT 2004 Digital Multimeter 91‑892647A01

Meter Test Leads Meter Scale Reading (Ω)

Red Black Ω
Forward and reverse No continuity
Green Green
Neutral 0 Ω (Continuity)

Removal
1. Remove the starter cable from the starter terminal.
2. Disconnect the neutral start safety switch harness leads.
3. Use a 19 mm open end wrench to hold the lower jam nut.
4. Use a 14 mm open end wrench to rotate the neutral start safety switch counterclockwise to loosen.
5. Slide the switch and actuator forward.

Page 7A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

6. Remove the neutral start safety switch from the actuator.

c
e
b

d
d
18752

Port Side Starboard Side

a - Starter terminal
b - Bracket
c - 14 mm flat on switch
d - Actuator
e - 19 mm hex jam nut

Installation
1. Install the actuator between the switch and jam nut.
2. Slide the switch and actuator into the bracket.
3. Use a 19 mm open end wrench to hold the lower jam nut.
4. Use a 14 mm open end wrench to rotate the neutral start safety switch clockwise to tighten.
5. Connect the green neutral start safety switch bullet leads.
6. Install the starter cable to the starter terminal. Secure with a nut. Tighten the nut to the specified torque.

Description Nm lb. in. lb. ft.

Starter terminal nut 4 35
7. Install the electrical bracket cover.

Throttle Only Removal and Disassembly

Removal
1. Remove the bottom cowl upper clamp. Remove the shift/throttle cables and the throttle link. Refer to Section 7B ‑ Tiller
Handle Removal.
2. Remove the two throttle rods from the throttle lever. Refer to Section 7B ‑ Tiller Handle Removal.
3. Remove the throttle only button retainer clip from the cowl.
4. Remove the retainer, grommet, and throttle only button.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-9

Throttle/Shift Linkage

5. Remove the three bolts securing the throttle only assembly to the powerhead.

a- Throttle lever
a b- Throttle only button retainer clip
c- Grommet and throttle only button retainer
d- Throttle only button
e e- Bolt (3)

d 18319

6. Remove the upper shift shaft from the shift lever.

7. Remove the starter interlock cable from the lever.
8. Slide the shift lever shaft out from the shift detent.

a- Shift lever shaft

c b- Starter interlock cable installed in lever
c- Starter interlock cable
d- Upper shift shaft installed in shift lever
b

d a

18323

9. Remove the bolt securing the detent spring to the shift detent support bracket. Remove the detent spring and detent.
10. Remove the shift detent.

a - Shift detent
b b - Shift detent spring
c - Bolt

c
a

18333

Disassembly
1. Remove the three bolts from the gear plate halves. Separate the gear plates.
2. Remove the nut from the drive gear assembly bolt.

Page 7A-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

3. Remove the gear components from the outer gear plate.

a
a- Drive gear bolt
b b- Bushing
c c- Throttle opener
d
e d- Washer
e- Drive gear pulley
f f- Gear plate
g- Drive gear
g h- Bushing
k i- Washer
h j- Nut
i k- Gear plate
j l- Bolt
m- Driven gear
l

m
18425

4. Inspect all components for cracks and wear. Replace as required.

Throttle Only Reassembly and Installation

Reassembly
1. Install the spring and actuator into the shift lever shaft. While pushing on the actuator, install the retaining pin through the
shaft.

b c
a

11902

a- Actuator
b- Spring
c- Pin
d- Shift lever shaft

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-11

Throttle/Shift Linkage

2. Install the drive and driven gears, aligned in neutral position, on the outer gear plate. Lubricate the gears with 2‑4‑C with
PTFE.

b a- Outer gear plate

b- Drive gear
a c- Driven gear
c d- Gear teeth aligned in neutral position

d
18698

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Throttle only drive and driven gears 92-802859A 1
3. Install the throttle pulley on the drive gear.

b a - Throttle pulley
b - Drive gear
a

18734

4. Install the bolt through the throttle lever components and the drive gear/gear plate.

a- Bolt
b- Washer
c- Bushing
d- Throttle opener
e- Washer
a b c d e f f- Bushing
g- Throttle pulley

g
18737

Page 7A-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

5. Install a washer and nut. Tighten the nut to the specified torque.

a - Washer and nut

a b - Throttle only components

18738

Description Nm lb. in. lb. ft.

Nut 6 53

Installation
1. Place the shift detent in the shift detent bracket.
2. Apply 2‑4‑C with PTFE to the shift detent.

a - Shift detent
b - Shift detent bracket

18835

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Shift detent 92-802859A 1
3. Position the shift lever shaft with reference to the shift detent as shown.
NOTE: The illustration is for reference to show alignment of the shift lever shaft and the shift detent.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-13

Throttle/Shift Linkage

4. Install the shift lever shaft into the shift detent.

a
18298
d
b

a- Shift detent (installed on engine)

b- Shift lever shaft
c- Shift lever
d- Starter interlock lever

5. Install the shift detent spring and bolt. Tighten the bolt to the specified torque.

a - Shift detent
b b - Shift detent spring
c - Bolt

c
a

18333

Description Nm lb. in. lb. ft.

Shift detent spring bolt 6 53
6. Install the upper shift shaft into the shift lever.
7. Install the starter interlock cable into the starter interlock lever.

a- Shift lever shaft

c b- Starter interlock cable installed in lever
c- Starter interlock cable
d- Upper shift shaft installed in shift lever
b

d a

18323

8. Install the throttle only assembly to the shift lever shaft.

9. Attach the throttle only assembly to the powerhead with three bolts. Tighten the bolts to the specified torque.

Page 7A-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage

10. Install the throttle only button, grommet, and retainer.

11. Install the throttle only button retainer clip.

a- Throttle lever
a b- Throttle only button retainer clip
c- Grommet and throttle only button retainer
d- Throttle only button
e e- Bolt (3)

d 18319

Description Nm lb. in. lb. ft.

Throttle only attaching bolts (3) 6 53
12. Install the throttle link to the throttle lever. Refer to Section 7B ‑ Tiller Handle.
13. Install the throttle cables to the throttle only pulley. Refer to Section 7B ‑ Tiller Handle.
14. Install the grommet and bottom cowl upper clamp. Refer to Section 7B ‑ Tiller Handle.

Remote Control Models

Shift Control Removal and Disassembly
1. Remove the three bolts securing the bottom cowl cover and remove the cover.

a a

a 18863

a - Bolt (3)
b - Bottom cowl cover

2. Remove the bolt securing the remote control cable clamp.

3. Remove the cotter pins and washers on the remote control throttle and shift cables.
4. Remove the cotter pins and washers on the shift rod.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-15

Throttle/Shift Linkage
5. Remove the shift rod, throttle cable, and shift cable.

a a - Cable clamp
c b
b - Bolt
c - Shift cable cotter pin
and washer
d - Throttle cable cotter
pin and washer
d e - Shift rod cotter pins
and washers

18875

6. Remove the bolts securing the shift and throttle rod brackets.
7. Remove the brackets and the harness clamp.

a
c d

18942

a- Shift arm
b- Shift arm bracket bolt (2)
c- Harness clamp
d- Throttle arm bracket
e- Throttle arm bracket bolt (2)

8. Remove the bolts securing the remote control bracket.

a - Remote control bracket

b - Remote control bracket bolt (2)
c - Shift lever shaft

a
b

18898

Page 7A-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage
9. Remove the neutral interlock cable and the upper shift shaft from the shift lever shaft.
10. Slide the shift lever shaft out from the shift lever shaft bracket.

a- Shift lever shaft

b- Shift lever shaft bracket
c c- Upper shift shaft
d- Neutral interlock cable
d

b
a

18899

11. Remove the bolt in the end of the shift arm to disassemble the shift lever shaft.

a- Bolt and washer

b- Shift arm
c- Shift lever shaft
d d- Remote control bracket

c
a
b
18908

Shift Control Assembly and Installation

1. Assemble the shift lever shaft components as shown. Tighten the bolt to specified torque.
2. Apply 2‑4‑C with PTFE to the end of the shift lever shaft that rotates in the shift lever shaft bracket.

a- Bolt and washer

b- Shift arm
c- Remote control bracket
d- Shift lever shaft

b
a
d

c
18911

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-17

Throttle/Shift Linkage

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Shift lever shaft 92-802859A 1

Description Nm lb. in. lb. ft.

Shift lever shaft bolt 6 53
3. Install the shift lever shaft into the shift lever shaft bracket.
4. Install the upper shift shaft into the shift lever.
5. Install the neutral interlock cable into the slot on the lever. Ensure that the cable is aligned in the slot.

a- Shift lever shaft

b- Shift lever shaft bracket
c c- Upper shift shaft
d- Neutral interlock cable
d

b
a

18899

6. Attach the remote control bracket to the engine with two bolts. Tighten the bolts to the specified torque.

a - Remote control bracket

b - Remote control bracket bolt (2)
c - Shift lever shaft

a
b

18898

Description Nm lb. in. lb. ft.

Remote control bracket bolts (2) 6 53
7. Install the throttle arm and bracket. Tighten the two bolts to the specified torque.

Page 7A-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Throttle/Shift Linkage
8. Attach the throttle link rod to the throttle.

b a a- Throttle
b- Throttle link rod
c- Throttle arm
c d- Bolt (2)
e- Remote control bracket bolt
e (2)
d

18941

Description Nm lb. in. lb. ft.

Throttle arm bracket bolts (2) 6 53
9. Install the shift arm and bracket.
10. Attach the harness clip.
11. Install the two bolts. Tighten the two bolts to the specified torque.

a
c d

18942

a- Shift arm
b- Shift arm bracket bolt (2)
c- Harness clamp
d- Throttle arm bracket
e- Throttle arm bracket bolt (2)

Description Nm lb. in. lb. ft.

Shift arm bracket bolts (2) 6 53
12. Install the shift rod, throttle cable, and shift cable.
13. Install the cotter pins and washers on the shift rod.
14. Install the cotter pins and washers on the remote control throttle and shift cables.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7A-19

Throttle/Shift Linkage
15. Install the remote control cable clamp over the remote control cables. Tighten the bolt to the specified torque.

a a - Cable clamp
c b
b - Bolt
c - Shift cable cotter pin
and washer
d - Throttle cable cotter
pin and washer
d e - Shift rod cotter pins
and washers

18875

Description Nm lb. in. lb. ft.

Remote control cable clamp bracket bolt 6 53
16. Install the remote control cables in the grommet. Install the grommet in the bottom cowl.
17. Install the bottom cowl cover. Tighten the three bolts to specified torque.

a a

a 18863

a - Bolt (3)
b - Bottom cowl cover

Description Nm lb. in. lb. ft.

Bottom cowl cover bolts (3) 6 53

Page 7A-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

Attachments
Section 7B - Tiller Handle
Table of Contents
Tiller Handle Components................................................. 7B-4 Tiller Handle Disassembly............................................... 7B-11
Tiller Handle Operation...................................................... 7B-6 Throttle Cable Case......................................................... 7B-14
Throttle Cable/Linkage Adjustments.................................. 7B-6 Disassembly/Inspection............................................ 7B-14
Throttle Cables........................................................... 7B-6 Assembly.................................................................. 7B-14
Linkage....................................................................... 7B-7 Tiller Handle Assembly.................................................... 7B-15
Power Trim Switch (Power Trim Models)...........................7B-7 Shift/Throttle Cable Position Reference...........................7B-20
Removal......................................................................7B-7 Tiller Handle Installation...................................................7B-21
Installation...................................................................7B-9 Carry Handle/Tiller Handle....................................... 7B-21
Tiller Handle Removal......................................................7B-10 Stop Wire Connections............................................. 7B-22
Throttle Cables......................................................... 7B-10 Throttle Cables......................................................... 7B-22
Stop Wire Connections............................................. 7B-11 Linkage and Grommet.............................................. 7B-23
Tiller Handle and Bracket......................................... 7B-11

7
B

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-1

Tiller Handle

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
7 Loctite 271 Threadlocker Carry handle/tiller handle assembly mounting bolts 92-809819

Page 7B-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-3

Tiller Handle

Tiller Handle Components

27 25

26

28 40

35
41
31
29 32 33
1
34 36
30 43
37 42

14
14 38
39
13

10
9
3
8
12
11

2 15
16
5
17
18

6
22
21
20
19

24 23
16665

Page 7B-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

Tiller Handle Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Tiller handle kit
2 1 Tiller handle
3 1 Lock cap
4 1 Inner grip
5 1 Lanyard stop switch
6 1 Outer grip
7 1 Throttle decal
8 1 Throttle shaft
9 1 Screw 2.3 20
10 1 Washer
11 1 Cover
12 1 Pulley
13 1 Throttle shaft case
14 2 Throttle cable
15 1 Clamp
16 1 Screw Drive tight
17 1 Throttle shaft bracket
18 1 Screw 5.6 50
19 1 Bolt
20 1 Throttle friction clamp
21 1 Spring
22 1 Friction adjusting knob As required
23 1 Switch housing
24 1 Power tilt switch
25 1 Carry handle
26 2 Bolt 30 22
27 2 Washer
28 1 Stop switch assembly
29 1 Retainer
30 1 Lanyard assembly
31 1 Cover
32 1 Screw Drive tight
33 2 Screw Drive tight
34 1 Tiller handle latch
35 1 Button
36 1 Collar
37 1 Spring
38 2 Washer
39 2 Bushing
40 1 Cover
41 1 Bolt 6 53
42 1 Bolt 6 53
43 1 Throttle lock decal

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-5

Tiller Handle

Tiller Handle Operation

1. The tiller handle can be placed in three positions for operation, storage, or transportation.

3272

2. To release the lever from one position and move it to another position, push the tiller lock release lever and move the tiller
handle.

a - Tiller lock release lever

a
3274

3. The tiller handle can be locked in the up position by removing the lock cap on top of the tiller handle. When the lock cap is
removed, the handle functions are the same as when the lock cap is in place except that the handle locks in the up
position. Push the tiller lock release lever to release the handle from the locked up position.

a - Lock cap
a b b - Locking mechanism

3273

Throttle Cable/Linkage Adjustments

Throttle Cables
1. Rotate the tiller twist grip to the neutral position.
2. Adjust the cable lengths using the jam nuts to bring match marks into alignment.
• Make adjustments to the lower cable first.

Page 7B-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

• Remove slack in the upper cable by adjusting the upper jam nuts. Do not overtighten.

a b c Neutral position
d a - Match mark on shift/throttle pulley
b - Match mark on gear plate
c - Jam nuts
d - Upper shift/throttle cable (reverse when
pulled in direction of arrow)
e - Lower shift/throttle cable (forward when
pulled in direction of arrow)

e
c
18091

3. Rotate the tiller throttle handle from forward wide‑open throttle to reverse wide‑open throttle. Verify that match marks are in
alignment. Readjust if necessary.
4. Rotate the handle to the neutral position. Ensure that the following conditions are met:
• Gearcase is in neutral (propeller rotates in both directions).
• Neutral start interlock lever is centered, allowing starter sheave to rotate.
• Reverse tilt lock is engaged.
5. Rotate the handle to the forward position. Ensure that the following conditions are met:
• Gearcase is in forward gear.
• Neutral start interlock lever is engaged preventing starter sheave rotation.
• Reverse lock is disengaged.
6. Rotate the handle to the reverse position. Ensure that the following conditions are met:
• Gearcase is in reverse gear.
NOTE: It may be necessary to rotate propeller shaft when shifting to reverse gear.
• Neutral start interlock lever is engaged.
• Reverse tilt lock is engaged.

Linkage
Refer to Section 2C ‑ Throttle Linkage Adjustment for adjustments.

Power Trim Switch (Power Trim Models)

Removal
NOTE: The power trim switch may be removed without removing the tiller handle and carry handle from the outboard.
1. Disconnect the power trim switch wires from the power trim relays. Refer to Section 5B ‑ Power Trim Electrical Circuit.
2. Remove the three screws and the cover from the carry handle.
3. Pry the power trim switch housing from the tiller handle.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-7

Tiller Handle

4. Remove the screw and power trim switch harness clamp from the tiller handle.

a - Power trim switch

housing
b - Power trim switch
c c harness clamp
c - Carry handle cover
screw (3)

b a

13952

5. Remove the power trim switch harness by pulling harness through the carry handle and tiller handle.

a a - Carry handle opening

b - Tiller handle opening
c - Power trim switch harness

13954

6. Loosen the power trim switch from the housing by pushing a thin blade screwdriver through the hole in the housing.
Remove the power trim switch from the housing.

d d
a b
13953

a- Screwdriver
b- Power trim switch housing
c- Power trim switch
d- Lock tab

Page 7B-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

Installation
1. Install the power trim switch into the power trim switch housing. Ensure that the switch is secured in the housing with lock
tabs.

a - Power trim switch

b - Power trim switch housing
c - Lock tabs

b
c c
13958

2. Route the power trim switch harness through the tiller handle and carry handle.
3. Install the power trim switch housing onto the throttle shaft.

a - Power trim switch and housing

a
b - Power trim switch housing mounting
clip
b
c - Throttle shaft
c

13956

4. Install the power trim switch harness clamp and screw. Tighten screw securely.
5. Attach the cover to the carry handle with three screws. Tighten screws securely.

a - Power trim switch

housing
b - Power trim switch
c c harness clamp
c - Carry handle cover
screw (3)

b a

13952

6. Connect the power trim switch wires to the power trim relays. Refer to Section 5B ‑ Power Trim Electrical Circuit.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-9

Tiller Handle

Tiller Handle Removal

Throttle Cables
1. Remove the three lower cowl cover attaching screws and grommet.

d
c 18093

a- Lower cowl cover screw (2)

b- Grommet
c- Lower cowl cover screw (1)
d- Lower cowl cover

2. Rotate the tiller twist grip to the neutral position.

3. Ensure that the gearcase is in neutral and the neutral start interlock is engaged.
4. Ensure that the pointer on the throttle cable pulley is aligned with the mark on the bracket.
5. Remove the cotter pin and washer from the throttle rod.
6. Remove the throttle rod from the throttle arm and throttle opener.
7. Loosen cable jam nuts on both the upper and lower cable ends.
8. Remove both throttle cables from the bracket slots. Remove both cable ends from the pulley.
NOTE: For easier installation, mark cables for respective position.

a
b

f
e b
d c
18095

a- Marks aligned in neutral position

b- Control cable jam nuts
c- Throttle opener
d- Throttle rod
e- Cotter pin and washer
f- Throttle arm

Page 7B-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

Stop Wire Connections

Disconnect the black/yellow and black lanyard stop switch and tiller handle stop button wire bullet connectors.

a- Black (lanyard stop switch)

b- Black/yellow (tiller handle stop button)
c- Brown (engine harness)
b d- Black (engine harness)
a c e- Black/yellow (lanyard stop switch)
f- Black (tiller handle stop button)

f e 18096

Tiller Handle and Bracket

1. Remove the two bolts securing the carry handle/tiller handle assembly to the outboard.
2. Remove the tiller handle assembly.

a - Carry handle/tiller handle assembly

a mounting bolts
b - Carry handle bracket

18099

Tiller Handle Disassembly

1. Remove the three screws securing the cover to the carry handle.

a- Carry handle cover screws

b c b- Tiller handle
c- Carry handle
d- Wire harness and cables

a d
13813

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-11

Tiller Handle
2. Remove the two bolts securing the carry handle end cover.

a - Carry handle end cover

b - Bolt (2)

b a
13818

3. Remove the bushing from the carry handle.

4. Remove the tiller handle latch and spring.

c a- Bushing
d
b- Carry handle
c- Spring
d- Tiller handle latch

a
13852

5. Separate the tiller handle and carry handle while pulling the throttle cable ends and tiller handle stop switch wires through
the carry handle.

a - Carry handle
b - Tiller handle

a b

13875

6. Remove the screw from the throttle shaft bracket.

7. Remove the throttle shaft bracket.
8. Loosen the throttle shaft friction control knob.

Page 7B-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle
9. Remove the washer and bushing.

d a - Throttle shaft retainer screw

b - Throttle shaft bracket
c - Throttle shaft friction control knob
and clamp assembly
e d - Throttle cable pulley housing
e - Washer
f - Bushing
c b a f
2993

10. Remove the throttle handle while pulling the throttle shaft/grip and pushing on the throttle shaft friction control knob.
11. Remove the throttle cable pulley housing.

b a c a - Throttle shaft friction control

knob
b - Throttle shaft/grip
c - Throttle cable pulley housing

2994

12. Remove the rubber grip from the throttle handle. Use a flat tip screwdriver to pry/push the rubber grip off the throttle
handle.

a - Throttle handle
a b b - Rubber grip

2997

13. Remove the stop button and wires.

14. Remove the throttle shaft friction control knob assembly.

a - Stop button/wire assembly

b - Throttle shaft friction
control knob and clamp
a assembly

2998

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-13

Tiller Handle
15. Remove the throttle shaft from the throttle handle.

a b a - Throttle shaft
b - Throttle handle

2996

Throttle Cable Case

Disassembly/Inspection
1. Remove screw and remove cover from cable holder.
2. Remove cables and pulley from case.
3. Inspect pulley for cracks. Inspect cables for kinks, frayed, or broken cables. Ensure that cables slide freely in outer jacket.
4. If any defects are found, replace component.

d b

e c
3008

a- Cable case
b- Pulley
c- Cover
d- Cables
e- Screw and washer

Assembly
1. Install cable end barrel into slot on pulley.

b a - Throttle cable
a
b - Cable end barrel in slot
c - Pulley

a b
3009

2. Install pulley with cables into case.

Page 7B-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

3. Ensure that cable ends are fully positioned in case.

a - Cable ends positioned in case

a

a 3010

4. Hold cables in place and install cover with screw and washer.
5. Rotate pulley and ensure that cables move freely in the correct direction.

b 2967

a - Forward throttle cable

b - Reverse throttle cable

Tiller Handle Assembly

1. Install the throttle handle onto the throttle shaft.

b
a

3016

a - Throttle shaft
b - Throttle handle

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-15

Tiller Handle
2. Install the stop button wires through the throttle shaft.

b a a - Stop button wires

c
b - Throttle handle
c - Throttle shaft

2995

3. Seat the stop button in the end of the throttle shaft/handle.

4. Install the throttle shaft friction control knob assembly.

a
b

3017

a - Stop button
b - Throttle shaft friction control knob and clamp assembly

5. Install the rubber grip onto the throttle handle.

a b a - Throttle handle
b - Rubber grip

3095
6. Feed the stop button wires through the throttle cable pulley housing.
7. Install the throttle cable pulley housing into the tiller handle.
8. Install the throttle handle assembly onto the tiller handle.

Page 7B-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle
9. Align the throttle shaft friction control knob assembly with slot in the tiller handle. Install the throttle shaft friction control
knob in the tiller handle.

b a- Stop button wires

b- Throttle cable pulley housing
c- Throttle shaft
a d- Throttle shaft friction control
knob assembly
c a e - Throttle cables
d

3139

10. Turn the throttle handle to the neutral position. The cable ends should be equal in length to ensure alignment of the throttle
shaft and the cable pulley.

b a a - Neutral position on throttle handle

b - Throttle position mark
c - Cable ends of equal length

c
3145

11. Insert the throttle shaft into the throttle cable pulley housing.
12. Route the stop button wires around the notch in the throttle cable pulley housing.
13. Install a washer and bushing on the tiller handle.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-17

Tiller Handle
14. Install the throttle shaft bracket. Tighten the screw to the specified torque.

a c b
g

d
e
f 3152

a- Throttle shaft
b- Throttle cable pulley housing
c- Throttle shaft bracket
d- Throttle shaft retainer screw
e- Washer
f- Bushing
g- Notch for stop button wires

Description Nm lb. in. lb. ft.

Throttle shaft retainer screw 5.6 50
15. Guide the cables and the stop button wire through the hole in the carry handle. Align the cables and stop button wire in the
carry handle channel and through the opening in the carry handle.
16. Attach the tiller handle to the carry handle.

a- Carry handle
b- Rubber washer
c- Bushing
a d- Tiller handle

b d
c

13859

Page 7B-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle
17. Attach the cover to the carry handle with three screws. Tighten screws securely.

a - Carry handle cover screws

a

13865

18. Install the spring tang into the small hole in the tiller handle latch.

a - Tiller handle latch

a
b - Spring tang installed in small hole
c - Tilt latch spring

b
13867

19. Assemble the tiller handle latch and spring into the carry handle. Ensure that the other spring tang is positioned as shown.

a- Tiller handle latch

b- Spring
c- Spring tang
d- Carry handle support wall

d c b
a
13872

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-19

Tiller Handle
20. Install the bushing into the carry handle through the tiller handle latch and loop in the spring.

c a- Bushing
d
b- Carry handle
c- Spring
d- Tiller handle latch

a
13852

21. Assemble the carry handle end cover to the carry handle. Tighten bolts to the specified torque.

a - Carry handle end cover

b - Bolt (2)

b a
13818

Description Nm lb. in. lb. ft.

Carry handle end cover bolts 6 53

Shift/Throttle Cable Position Reference

NOTE: The term forward cable and reverse cable refers to the control cable that is pulling to shift the outboard in that direction.

Forward
a a - Reverse cable
e b - Reverse cable end
c - Forward cable
d - Throttle rod
e - Throttle rod
b
d

c 18153

Page 7B-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

d a Neutral
a - Reverse cable
b - Forward cable
c - Reverse cable end
b d - Forward cable end

c
18154

Reverse
a a - Reverse cable
b - Forward cable end
c - Forward cable

c 18155

Tiller Handle Installation

Carry Handle/Tiller Handle
1. Apply Loctite 271 Threadlocker to the two carry handle mounting bolts.
2. Align the tiller handle assembly with the outboard.
3. Install the two bolts securing the carry handle/tiller handle assembly to the outboard. Tighten the mounting bolts to the
specified torque.

a - Carry handle/tiller handle assembly

a mounting bolts
b - Carry handle bracket

18099

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Carry handle/tiller handle assembly mounting bolts 92-809819

Description Nm lb. in. lb. ft.

Tiller handle assembly mounting bolts 30 22.1

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-21

Tiller Handle

Stop Wire Connections

1. Connect the lanyard switch black/yellow and black wire bullet connectors to the black/yellow and black stop switch bullet
connectors.
2. Connect the loose black wire bullet connector (from the lanyard stop switch) to the black wire bullet connector.
3. Connect the loose black/yellow wire bullet connector (from the lanyard stop switch) to the brown wire bullet connector.

a- Black (lanyard stop switch)

b- Black/yellow (tiller handle stop button)
c- Brown (engine harness)
b d- Black (engine harness)
a c e- Black/yellow (lanyard stop switch)
f- Black (tiller handle stop button)

f e 18096

Throttle Cables
1. Rotate the tiller twist grip to the neutral position.
2. Install the reverse throttle cable end in the reverse cable slot in the pulley.
3. Wrap the cable in the inner groove around the top side of the pulley.

a - Reverse cable
b - Reverse cable slot

b
18144

4. Rotate the tiller twist grip counterclockwise until the reverse cable slot in the pulley is near the top.
5. Install the forward cable end in the forward cable slot in the pulley.

Page 7B-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

6. Wrap the forward cable in the outer groove around the top side of the pulley.

a - Forward cable
b - Forward cable slot

18145

7. Rotate the tiller handle to the neutral position.

8. Place the reverse cable jacket into the upper slot of the anchor bracket.
9. Place the forward cable jacket into the lower slot of the anchor bracket.

a - Reverse cable
b - Upper slot in anchor
a bracket
c - Lower slot in anchor
b bracket
d - Forward cable
e - Reverse cable end
f - Forward cable end
f

e c
d 18158

10. Adjust the shift/throttle cables. Refer to Throttle Cable/Linkage Adjustments preceding.

Linkage and Grommet

1. Install the throttle rod to the throttle opener.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-23

Tiller Handle

2. Install the throttle to the throttle arm and install the washer and cotter pin.

a
b

f
e b
d c
18095

a- Marks aligned in neutral position

b- Control cable jam nuts
c- Throttle opener
d- Throttle rod
e- Cotter pin and washer
f- Throttle arm

3. Route the lanyard stop switch and tiller handle stop button wires and shift/throttle cables through the grommet.
4. Install the lower cowl cover.

a - Lanyard stop switch and tiller handle stop button

wires
b - Reverse shift/throttle cable
c - Forward shift/throttle cable
b d - Grommet
e - Lower cowl cover
c
a
e

d 18104

Page 7B-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Tiller Handle

5. Install the three lower cowl cover attaching screws. Tighten the screws to the specified torque.

d
c 18093

a- Lower cowl cover screw (2)

b- Grommet
c- Lower cowl cover screw (1)
d- Lower cowl cover

Description Nm lb. in. lb. ft.

Lower cowl cover screws 6 53

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 7B-25

Tiller Handle

Notes:

Page 7B-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter

Manual Starter
Section 8A - Recoil Starter
Table of Contents
Recoil Starter Components................................................8A-4 Recoil Starter Assembly............................................. 8A-8
Recoil Starter..................................................................... 8A-6 Recoil Starter Installation..........................................8A-12
Recoil Starter Removal...............................................8A-6 Neutral Interlock Cable Adjustment.......................... 8A-13
Recoil Starter Disassembly.........................................8A-7

8
A

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-1

Recoil Starter

Lubricant, Sealant, Adhesives

Tube Ref No. Description Where Used Part No.
7 Loctite 271 Threadlocker Threads of the friction plate retaining bolt 92-809819
Recoil housing
95 2-4-C with PTFE Starter pawl bore on the recoil sheave 92-802859A 1
Friction plate

Page 8A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-3

Recoil Starter

Recoil Starter Components

29 32
33
34
30 30
31

23
25

27 26

24

3 20
28 1
21
22

2
20
21 19

5
4
6

8
7
9

10

11 18
12
13 14

15
16
17 16664

Page 8A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter

Recoil Starter Components

Ref. Torque
No. Qty. Description Nm lb. In. lb. ft.
1 1 Recoil starter
2 1 Starter housing
3 1 Spring
4 1 Starter handle
5 1 Cap
6 1 Starter lock
7 1 Starter rope
8 1 Starter spring
9 1 E‑ring
10 1 Reel
11 1 Friction spring
12 1 Friction plate
13 1 Bolt 6 53
14 1 Ratchet
15 1 Ratchet guide
16 1 Return spring
17 1 Starter pulley
18 3 Screw (M6 x 16) 6 53
19 1 Seal
20 3 Bolt 6 53
21 3 Washer
22 2 Nut
23 1 Starter lock cam spring
24 1 Lock cable
25 1 Belt cover
26 2 Collar
27 1 Bracket
28 1 Screw (M6 x 16) 6 53
29 2 Bolt 6 53
30 4 Washer
31 2 Collar
32 2 Bolt 6 53
33 1 Decal ‑ Spark plug (with resistance)
34 1 Decal ‑ Caution

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-5

Recoil Starter

Recoil Starter
Recoil Starter Removal
1. Remove the four bolts securing the timing belt cover to the cylinder block.
2. Remove the three bolts securing the recoil assembly to the engine block.

a - Bolts securing the recoil assembly

(3)
b - Bolts securing timing belt cover (4)

a
b

9698

3. Remove the bolt securing the harness connector bracket to the intake manifold.

20523

4. Remove the timing belt cover.

5. Do not lose the T‑nuts located in the recoil housing assembly.

20513

6. Pull the neutral interlock cable to disengage the neutral interlock cable from the recoil housing.

Page 8A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter
7. Lift the neutral interlock cable up and remove the neutral interlock cable tension spring from the recoil housing.

a a - Neutral interlock cable tension

b
spring
b - Neutral interlock cable

9696

Recoil Starter Disassembly

! WARNING
Uncontrolled release of the rewind spring can cause serious injury. Wear eye protection when servicing the rewind starter in
case spring should uncoil.

1. Cut or untie the recoil rope from the recoil handle.

2. Slowly allow the recoil starter sheave to unwind completely.
3. Rotate the recoil starter sheave clockwise to disengage the starter recoil spring from the sheave.
4. Remove the bolt securing the recoil friction plate to the recoil housing. Remove the recoil friction plate.

a- Recoil rope
b d b- Recoil sheave
c- Bolt securing recoil friction plate
a
d- Rotate recoil sheave clockwise
c

9719

5. Carefully remove the recoil starter sheave.

6. Remove the recoil spring if replacement is needed.
7. Disengage the interlock lever spring from the recoil lock.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-7

Recoil Starter
8. Pinch the recoil lock retainer and push the recoil lock out of the recoil housing.

a b a - Recoil lock
b - Interlock lever spring
c - Recoil lock retainer (pinch to remove)

9723

9. Remove the E‑ring securing the starter pawl to the starter sheave.

9725

10. Push the starter pawl out of the starter sheave.

Recoil Starter Assembly

! WARNING
Uncontrolled release of the rewind spring can cause serious injury. Wear eye protection when servicing the rewind starter in
case spring should uncoil.

1. Lubricate with 2‑4‑C with PTFE the area of the recoil housing where the recoil spring is located.
2. Install the recoil spring into the recoil housing.

a a - Recoil spring
b
b - Lubricate with 2‑4‑C with PTFE

9726

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Recoil housing 92-802859A 1
3. Tie a knot on one side of the recoil rope and insert the recoil rope through the recoil sheave.
4. Thread the recoil rope through the recoil sheave as shown.

Page 8A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter
5. Pull the recoil rope tight in the recoil sheave.

a a - To recoil handle

9727

6. Assemble the recoil pawl as shown.

9728

7. Lubricate the starter pawl bore on the recoil sheave with 2‑4‑C with PTFE.
8. Install the starter pawl return spring onto the recoil sheave.
9. Install the starter pawl onto the recoil sheave.

a b a - Starter pawl
b - Starter pawl return spring

9730

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Starter pawl bore on the recoil sheave 92-802859A 1
10. Secure starter pawl with the E‑ring retained during disassembly.

9725

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-9

Recoil Starter
11. The recoil sheave catch on the recoil sheave must interlock with the recoil spring for the recoil to function properly.

a a - Recoil spring
b - Recoil sheave catch

b
9732

12. Install the recoil sheave onto the recoil housing.

13. With a slight downward pressure, rotate the recoil sheave counterclockwise to engage the spring into the catch on the
recoil sheave. When the spring is properly positioned on the recoil sheave, resistance will be present while winding the
recoil sheave in a counterclockwise rotation.
14. Install the friction plate spring onto the friction plate. Lubricate the friction plate with 2‑4‑C with PTFE.

b a - Friction plate spring

a
b - Friction plate
c - Lubricate with 2‑4‑C with PTFE

c
9740

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Friction plate 92-802859A 1
15. Insert the friction plate spring through the wire loop.
16. Align the tabs on the recoil housing with the holes on the friction plate.
17. Apply Loctite 271 to the friction plate retaining bolt. Tighten the friction plate retaining bolt to the specified torque.

b a- Recoil pawl
b- Friction plate retaining bolt
c- Friction plate spring
d- Wire loop

c
d 9741

Description Nm lb. in. lb. ft.

Friction plate bolt 6 53

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Threads of the friction plate retaining bolt 92-809819
18. Insert the recoil rope into the guide and through the recoil housing.
19. Insert the rope end through the recoil handle.

Page 8A-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter
20. Tie a knot as shown. Place the rope knot into the rope retainer and insert into the recoil handle.

9748

21. Insert the recoil rope into the notch on the recoil sheave.
22. Wind the recoil sheave three turns counterclockwise to preload the recoil spring.

a- Recoil rope
b- Recoil sheave notch
c- Recoil rope guide
a b d- Recoil housing opening

d
9743

23. Allow the recoil rope to retract into the recoil sheave.
24. Ensure the recoil rope retracts and extends fully.
25. Insert the recoil lock into the recoil housing.
26. Push the recoil lock until it snaps into place.

a b a - Recoil lock
b - Recoil sheave
c - Recoil lock bore
c

9749

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-11

Recoil Starter
27. Place the interlock lever spring onto the recoil lock.

a b a - Recoil lock
b - Interlock lever spring
c - Recoil lock retainer

9723

Recoil Starter Installation

1. Install the neutral interlock cable tension spring onto the recoil housing catch and the neutral interlock cable end.
2. Pull on the neutral interlock cable and insert the cable end into the neutral interlock cable retainer on the recoil housing.

a
a - Recoil housing catch
b
b - Neutral interlock cable retainer

9717

3. Install the recoil assembly onto the cylinder block and secure with three bolts. Do not tighten the bolts at this time.
4. Ensure the T‑nuts are installed in the recoil housing assembly.

20513

5. Install the timing belt cover. Ensure the aft mounting of the timing belt cover is supported by two spacers.
6. Align the harness connector bracket with the timing belt cover and install a bolt. Do not tighten the bolts at this time.

Page 8A-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Recoil Starter
7. Align the harness connector bracket with the intake manifold bolt hole. Secure the harness connector bracket with a bolt.
Tighten the bolt to the specified torque.

20523

Description Nm lb. in. lb. ft.

Harness connector bracket bolt 6 53

8. Install the remaining timing belt cover bolts. Tighten the timing belt cover bolts and the recoil housing bolts to the specified
torque.

a - Bolts securing the recoil assembly

(3)
b - Bolts securing timing belt cover (4)

a
b

9698

Description Nm lb. in. lb. ft.

Recoil retaining bolts (3) 6 53
Timing belt cover retaining bolts (4) 6 53

Neutral Interlock Cable Adjustment

1. Ensure the tiller handle control cables are properly adjusted.
2. Ensure the tiller handle is in neutral.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 8A-13

Recoil Starter
3. Loosen the interlock cable nuts.

a - Throttle cam
b - Interlock cable nuts

22639

4. Adjust the interlock cable nuts so the neutral interlock cable ball is centered on the recoil lock.

b a - Neutral interlock cable ball

b - Recoil lock

22640

Page 8A-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Jet Drive Outboard

Section 9A - Jet Drive Outboard
Table of Contents
Jet Unit Components......................................................... 9A-4 Bearing Carrier Installation....................................... 9A-15
Jet Water Pump Components............................................9A-6 Water Pump Installation............................................9A-16
Shift Linkage Components ‑ Jet Tiller Handle....................9A-8 Liner Installation........................................................9A-16
Shift Linkage Components ‑ Jet Remote Control.............9A-10 Jet Drive Installation................................................. 9A-17
Water Testing...................................................................9A-12 Shift Lever Removal and Installation (Tiller Models)........9A-20
Checking for Cavitation.............................................9A-12 Shift Lever Removal................................................. 9A-20
Jet Drive Disassembly..................................................... 9A-12 Shift Lever Installation.............................................. 9A-21
Jet Drive Removal.................................................... 9A-12 Shift Link Rod Removal and Installation (Tiller Models).. 9A-22
Water Pump Disassembly........................................ 9A-14 Shift Cam Adjustment (Tiller Models).............................. 9A-22
Bearing Carrier Removal.......................................... 9A-14 Shift Cam Adjustment (Remote Control Models)............. 9A-23
Liner Removal...........................................................9A-14 Neutral Interlock Cable (Remote Models)........................9A-24
Jet Drive Reassembly...................................................... 9A-15 Installation.................................................................9A-24

9
A

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-1

Jet Drive Outboard

Lubricants, Sealants, Adhesives

Tube Ref No. Description Where Used Part No.
Mounting flange on the water intake housing, mounting bolt
Extreme Grease 8M0071842
threads
Bearing carrier mounting screw threads
7 Loctite 271 Threadlocker 92-809819
Jet drive mounting bolt threads
Inside pump liner housing
Liner mounting bolts threads
95 2-4-C with PTFE 92-802859A 1
Driveshaft splines
Driveshaft and impeller bore

Page 9A-2 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Notes:

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-3

Jet Drive Outboard

Jet Unit Components

4
4 5
11
10
7 4 4 3
9
6 8
4
4 4
13
4
12
14 3 4
15
1

16

2 23

24
25
26
19

28
17

27
30
29 31

22
20
21 31
32

18 33

26149

Page 9A-4 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Jet Unit Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Housing
2 1 Lube hose
3 1 Reverse gate with bumper
4 1 Shift linkage kit
5 1 Shift cam
6 1 Adapter plate
7 1 Bolt 31 23
8 1 Washer
9 1 Stud bolt
10 1 Washer
11 1 Nut
12 4 Bolt 19 168 14
13 4 Washer
14 2 Bolt (M6 x 16) 6 53
15 2 Washer
16 1 Screw
17 1 Driveshaft
18 1 Sleeve
19 1 Nut 34 25
20 2 Bolt 3.4 30
21 4 Bolt 34 25
22 4 Washer
23 1 Impeller
24 1 Key
25 1 Shim
26 1 Tab washer
27 1 Intake housing assembly
28 1 Liner
29 1 Anode kit
30 2 Bolt (M6 x 25) 6 53
31 2 Washer
32 2 Bolt (M6 x 16) 11.3 100
33 6 Bolt (M6 x 20) 11.3 100

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-5

Jet Drive Outboard

Jet Water Pump Components

2 1

4 3

5 6

9
10

11

12

14
13

25828

Page 9A-6 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Jet Water Pump Components

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Grommet
2 1 Water tube
3 1 Seal
4 4 Bolt 6 53
5 4 Washer
6 1 Housing
7 1 Pump liner
8 1 Impeller
9 1 Key
10 1 Gasket
11 1 Guide plate
12 1 Gasket
13 1 Housing
14 2 Dowel pin

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-7

Jet Drive Outboard

Shift Linkage Components ‑ Jet Tiller Handle

1
4
2
3

6
7 10
8

5
8

12
13 14
9 11
19

15

16

12

17

18 25934
13 14

Page 9A-8 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Shift Linkage Components - Jet Tiller Handle

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Retainer
2 1 Washer
3 1 Spring
4 1 Retainer
5 1 Bushing
6 1 Seal
7 1 Washer
8 2 Bolt and washer
9 1 Plate
10 1 Shift lever
11 1 Pin
12 2 Clip
13 2 Lockwasher
14 2 Spring
15 1 Nut
16 1 Shift rod
17 1 Nut
18 1 Link rod
19 1 Link rod

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-9

Jet Drive Outboard

Shift Linkage Components ‑ Jet Remote Control

2
1
3

8
5
7 6

12
11

14
13
11 12

9
10
15
16
17

26151

Page 9A-10 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Shift Linkage Components - Jet Remote Control

Torque
Ref. No. Qty. Description Nm lb. in. lb. ft.
1 1 Screw
2 1 Washer
3 1 Clamp
4 1 Bracket
5 2 Bolt (M6 x 16) 6 53
6 2 Washer
7 1 Bolt
8 1 Nut
9 1 Bracket
10 1 Bolt (M6 x 16) 6 53
11 2 Lockwasher
12 2 Nut
13 1 Pivot bolt
14 1 Nut
15 1 Nut
16 1 Washer
17 1 Clip

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-11

Jet Drive Outboard

Water Testing
Checking for Cavitation
The initial outboard height setting should be close to the optimum setting for the outboard. However, because of the hull design
of some boats, obstructions, or imperfections in the hull ahead of the water intake, adjustments may be required to prevent
cavitation at running speeds.
When operating the boat, the outboard driveshaft housing should be vertical, or tilted toward the boat, when planing to provide
a scooping angle on the water intake. Tilting the outboard out beyond a vertical position reduces the scoop angle and can
cause impeller slippage and cavitation.
IMPORTANT: If the angle of the boat transom does not allow the driveshaft housing to be positioned vertical, a wedge kit
should be installed behind the transom brackets to increase the tilt‑in angle.
NOTE: Slight cavitation in sharp turns and rough water is acceptable, but excessive cavitation is harmful to the outboard and
should be avoided.
Test run the boat. If cavitation occurs (air enters the pump), the first thing to try is lowering the outboard mounting height.
If cavitation still exists after lowering the outboard, it may be helpful to seek advice from the boat manufacturer.
Another option to further reduce cavitation is a rough water plate.
A rough water plate may be helpful in reducing cavitation when running in windy, rough water conditions where air is sucked
into the water intake when jumping waves. Install a 0.8 mm (1/32 in.) metal plate that extends from the hull bottom to the top of
the water intake housing. This plate tends to reduce air intake as well as reduce spray.

a - Rough water plate

24906

Jet Drive Disassembly

Jet Drive Removal
1. Disconnect the shift linkage.
2. Remove the six mounting bolts securing the water intake housing and remove the water intake housing.

a - Mounting bolts
a b - Water intake housing

25729

3. Straighten the bent tabs on the nut retainer and remove the impeller nut.

Page 9A-12 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

4. Pull the impeller straight off the shaft. If the impeller is tight, use a hammer and a block of wood to rotate the impeller
clockwise on the shaft until the keyway is directly above the flat on the shaft. This will free the jammed key and allow
removal.

a- Plastic sleeve
b- Impeller
c- Shear key
d- Shims
e- Nut retainer
a f- Impeller nut

c
d
e
f
25730

5. Remove the five bolts securing the jet drive to the driveshaft housing. Remove the jet drive.

a a

25731

a - Bolt (4)
b - Bolt (1)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-13

Jet Drive Outboard

Water Pump Disassembly

Remove the four bolts securing the water pump assembly. Remove the water pump.

a b a- Bolt and flat washer (4)

b- Seal
c c- Water pump housing
d- Pump liner housing
e- Impeller
f- Key
d
g- Gasket
h- Water pump guide plate
e i- Gasket
j- Base
f k- Dowel pin

i
k
j

k
25742

Bearing Carrier Removal

Remove the two screws securing the bearing carrier to the jet drive. Remove the bearing carrier.

a - Screws
b - Bearing carrier

b a

25763

Liner Removal
1. Mark the mounting bolts for reassembly into the same holes. Remove the two mounting bolts.

Page 9A-14 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

2. Remove the liner. If the liner is tight, tap on the inner edge of the liner with a long drift punch through the intake grate.

a a - Liner
b - Mounting bolt (2)

25787

Jet Drive Reassembly

Bearing Carrier Installation
NOTE: Individual bearing carrier components are not sold separately. The bearing carrier must be serviced as an assembly.
1. Ensure the three O‑ring seals are in place.

a - O‑ring seals

25829

2. Place the bearing carrier into the jet drive and fasten with two screws. Apply Loctite 271 to the screw threads and tighten
the screws to the specified torque.

a - Screws
b - Bearing carrier

b a

25763

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Bearing carrier mounting screw threads 92-809819

Description Nm lb. in. lb. ft.

Bearing carrier mounting screws 3.4 30

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-15

Jet Drive Outboard

Water Pump Installation

IMPORTANT: It is recommended that the impeller be replaced regardless of appearance. If the impeller must be reused, it
must be installed in the direction of original rotation. Installing the impeller with the vanes reversed from the previous set will
result in vane breakage shortly after unit is returned to service.
1. Lubricate the inside of the pump liner housing with 2‑4‑C with PTFE.
2. Reassemble the water pump, as shown. Rotate the driveshaft clockwise while pressing the water pump housing down over
the impeller.
3. Fasten the water pump to the jet drive with four screws. Tighten the screws to the specified torque.

a b a- Bolt and flat washer (4)

b- Seal
c c- Water pump housing
d- Pump liner housing
e- Impeller
f- Key
d
g- Gasket
h- Water pump guide plate
e i- Gasket
j- Base
f k- Dowel pin

i
k
j

k
25742

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Inside pump liner housing 92-802859A 1

Description Nm lb. in. lb. ft.

Water pump cover screws 6 53

Liner Installation
1. Locate the holes in the liner with holes in the water intake housing.

Page 9A-16 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

2. Apply 2‑4‑C with PTFE to the threads on the mounting bolts and fasten the liner into the water intake housing. Tighten the
bolts to the specified torque.

a a - Liner
b - Mounting bolt (2)

25787

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Liner mounting bolts threads 92-802859A 1

Description Nm lb. in. lb. ft.

Liner mounting bolts 11.3 100

Jet Drive Installation

1. Remove and isolate the spark plug leads from the spark plugs.
2. Lubricate the splines on the driveshaft with 2‑4‑C with PTFE. Do not apply lubricant on the top surface of the driveshaft.

NOTICE
Installing the jet drive to the powerhead without adequately cleaning the top of the driveshaft can result in severe product
damage. Any lubricant trapped in the space between the driveshaft and the engine's crankshaft prevent the two from properly
engaging. Always clean the top of the driveshaft before installing the jet drive.

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Driveshaft splines 92-802859A 1
3. Guide the jet drive into the driveshaft housing, making sure the driveshaft engages the crankshaft and the water tube
enters the water pump seal.
4. Install the jet drive to the driveshaft housing with the five bolts shown. Apply Loctite 271 Threadlocker to the bolt threads
and tighten the bolts to the specified torque.

a a

25731

a - Lower bolts (4)

b - Upper bolt (1)

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-17

Jet Drive Outboard

Description Nm lb. in. lb. ft.

Lower bolts (4) 34.0 25
Upper bolt 31.0 23

Tube Ref No. Description Where Used Part No.

7 Loctite 271 Threadlocker Jet drive mounting bolt threads 92-809819
5. Lubricate the driveshaft and impeller bore with 2‑4‑C with PTFE.

Tube Ref No. Description Where Used Part No.

95 2-4-C with PTFE Driveshaft and impeller bore 92-802859A 1
6. Place the plastic sleeve inside the impeller and install the impeller, as shown.
7. Tighten the impeller nut on the shaft to remove any play between the impeller and shaft. If the tabs on the nut retainer do
not line up with the flats on the nut, remove the impeller nut and turn the nut retainer over. Tighten the impeller nut again.

a- Plastic sleeve
b- Impeller
c- Shear key
d- Shims
e- Nut retainer
a f- Impeller nut

c
d
e
f
25730

8. Temporarily install the water intake housing to check the impeller clearance. The clearance between the impeller and liner
should be 0.76 mm (0.03 in.). Shim washers can be transferred to either side of the impeller to raise or lower the impeller
to the correct clearance setting.

a - Shim washers
b - Impeller clearance

25824
b
Jet Drive
Clearance between impeller and liner 0.76 mm (0.03 in.)

Page 9A-18 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

9. After setting the impeller height, tighten the impeller nut to the specified torque. Secure the impeller nut by bending the tabs
on the nut retainer against the flats on the impeller nut.

a - Impeller nut
b - Nut retainer

a b 25825

Description Nm lb. in. lb. ft.

Impeller nut 34.0 25

NOTE: If the outboard is used in saltwater, apply Extreme Grease around the entire mounting flange on the water intake
housing and also to the threads on the mounting bolts.
10. Install the water intake housing with six bolts. Ensure the front of the housing is facing towards the front of the outboard.
Tighten the mounting bolts to the specified torque.

a - Mounting bolts
a b - Water intake housing

25729

Tube Ref No. Description Where Used Part No.

Mounting flange on the water intake housing, mounting bolt
Extreme Grease 8M0071842
threads

Description Nm lb. in. lb. ft.

Water intake housing mounting bolts 11.3 100

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-19

Jet Drive Outboard

Shift Lever Removal and Installation (Tiller Models)

Shift Lever Removal
1. Remove the three mounting bolts securing the access cover. Remove the access cover.

b b a - Access cover
b - Mounting bolt

25871

b
2. Remove the retainer that holds the bushing into the bottom cowl.

a - Retainer
b - Shift lever
a b

25872
3. Push back the spring‑loaded stopper to expose the cross pin. Remove the cross pin and slide the shift lever out of the
bottom cowl.

a - Cross pin
b - Stopper

25874

Page 9A-20 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

Shift Lever Installation

1. Assemble the components onto the shift lever, as shown.

d a- Stopper
b- Flat washer
a j c- Spring
h d- Retainer
b i e- Bushing
c f- Seal ring
e g- Nylon washer
f g
h- Screw and washer (2)
i- Plate
k j- Shift lever
l k- Retainer clip
m l- Flat washer
25875
n m- Spring
n- Shift rod

2. Slide the assembled shift lever into the cowl opening. Push the spring‑loaded stopper back. Insert the shaft into the
horizontal shift shaft and secure with the cross pin. Center the cross pin and rotate the stopper so it fits over the cross pin.

a - Cross pin
b - Stopper

25874
3. Fasten the bushing to the bottom cowl with the retainer.

a - Retainer
b - Shift lever
a b

25872

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-21

Jet Drive Outboard

4. Install the access cover with three bolts. Tighten the bolts to the specified torque.

b b a - Mountings bolts
b - Access cover

25871

Description Nm lb. in. lb. ft.

Access cover mounting bolts 10 88.5

Shift Link Rod Removal and Installation (Tiller Models)

Remove and install the shift rod, as shown.

a a- Clip
b- Flat washer
b c- Spring
c d- Shift link rod

a
b
c

25884

Shift Cam Adjustment (Tiller Models)

! WARNING
If not properly installed, the reverse gate can interfere with water coming off the rudder, suddenly and unexpectedly slowing
the boat. This can cause serious injury or death from occupants being thrown within or out of the boat. Adjust the shift cable
to prevent the reverse gate from interfering with water flow off the rudder.

Page 9A-22 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard
Check the shift link rod adjustment in forward shift position. The correct adjustment will position the shift cam far enough on the
roller in order to lock the reverse gate into forward position. The reverse gate should not be able to be forced up towards
neutral. Pull on the reverse gate by hand to verify.

a a- Shift link rod

b- Shift cam
b c- Roller
d- Reverse gate

d
25910

1. Place the shift handle into full forward shift position.

2. Adjust the length of the shift link rod so the roller is at the full end of travel (bottom) in the shift cam when the shift handle is
in forward.

Shift Cam Adjustment (Remote Control Models)

! WARNING
If not properly installed, the reverse gate can interfere with water coming off the rudder, suddenly and unexpectedly slowing
the boat. This can cause serious injury or death from occupants being thrown within or out of the boat. Adjust the shift cable
to prevent the reverse gate from interfering with water flow off the rudder.

1. Attach the shift cable to the shift cam with a flat washer and a self‑locking nylon insert locknut, as shown. Tighten the
locknut against the flat washer, then back‑off the locknut 1/4 turn.
2. Place the remote control handle into full forward position.
3. Adjust the shift cable adjustment barrel so that the roller is at the full end of travel (bottom) in the shift cam.
4. Attach the shift cable adjustment barrel to the bracket with a bolt and locknut. Tighten the bolt until it seats against the
adjustment barrel, then back‑off the bolt 1/4 turn. Hold the bolt from turning, and tighten the locknut on the bolt. The
adjustment barrel must be free to pivot.

d a- Roller
b- Shift cam
c- Shift cable
c d- Shift cable adjustment barrel

24905

5. Recheck the shift cable adjustment in forward shift position. The correct shift adjustment will position the cam far enough
on the roller to lock the reverse gate into forward position. Push on the reverse gate by hand to verify it is locked into
position. The reverse gate should not move when pushed toward the neutral position.
IMPORTANT: The forward locking of the reverse gate must be met. If not, readjust the shift cable.

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-23

Jet Drive Outboard

Neutral Interlock Cable (Remote Models)

Installation
1. Attach the top end of the cable to the starter lock cam spring and install the cable and spring to the rewind starter housing.

a b a - Neutral interlock cable

b - Starter lock cam spring

25979

2. Route the cable behind the electrical cover and out through the rubber grommet in the bottom cowl.

a - Neutral interlock cable

b - Electrical cover

b
a

25973

a - Rubber grommet
b - Neutral interlock cable

25972

3. Fasten the cable to the skirt on the starboard side with a clamp.

Page 9A-24 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 Jet Drive Outboard

4. Unthread the lower cable nut off the cable. Insert the cable wire into the slot in the retainer plate and attach the cable to the
retainer plate with the cable nuts. Tighten the cable nuts during adjustment.
5. Attach the bottom end of the cable to the shift cam with a flat washer and retainer.

b
a

e
d

f
25976

a- Cable nuts
b- Retainer plate
c- Clamp
d- Neutral interlock cable
e- Retainer
f- Flat washer

Adjustment
1. Position the remote control handle into neutral position.
2. Adjust the cable nuts so the neutral interlock cable ball is centered on the recoil lock. Tighten the nuts.

a a - Cable nuts

25977

90-8M0105568 eng MARCH 2016 © 2016 Mercury Marine Page 9A-25

Jet Drive Outboard

b a - Neutral interlock cable ball

b - Recoil lock

22640

3. Shift the outboard from forward to reverse several times.

4. Check the neutral interlock function in the forward, reverse, and neutral positions.

Page 9A-26 © 2016 Mercury Marine 90-8M0105568 eng MARCH 2016

 25/30 EFI

25/30 EFI & 25 EFI Jet

& 25 EFI Jet

S ERV IC E M A N U A L
S ERVI CE

MANUAL

www.mercurymarine.com.au www.mercurymarine.com www.brunswick-marine.com

41-71 Bessemer Drive P.O. Box 1939 Parc Industriel de Petit-Rechain
B-4800 Verviers, Belgium
MARCH 2016
90-8M0105568

Dandenong South, Victoria 3175 Australia Fond du Lac, WI 54936-1939 USA

© Mercury Marine. All rights reserved. 90-8M0105568 MARCH 2016

Printed in U.S.A.