POWERHEAD

POWERHEAD
Section 4A
Table of Contents
Powerhead Specifications . . . . . . . . . . . . . . . . 4A-1 Crankshaft . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-31
Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-2 Crankshaft (and End Cap) Bearings . . . . 4A-32
Powerhead Repair Stand . . . . . . . . . . . . . . 4A-3 Reed Block Assembly . . . . . . . . . . . . . . . . . 4A-33
Cylinder Block and End Caps . . . . . . . . . . . . . 4A-4 End Bearing Bleed System . . . . . . . . . . . . 4A-33
Exhaust Manifold and Exhaust Plate . . . . . . . 4A-6 Connecting Rods . . . . . . . . . . . . . . . . . . . . . 4A-33
Cylinder Head . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-8 Thermostats . . . . . . . . . . . . . . . . . . . . . . . . . 4A-36
Crankshaft, Pistons and Powerhead Reassembly and Installation . . . 4A-37
Connecting Rods . . . . . . . . . . . . . . . . . . . . . . . . 4A-10 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-37
Torque Sequence . . . . . . . . . . . . . . . . . . . . . . .
General Information . . . . . . . . . . . . . . . . . . . . .
4A-12
4A-14
Crankshaft Installation . . . . . . . . . . . . . . . .
Piston and Connecting Rod
4A-40
4
Powerhead Removal from Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . 4A-42 A
Driveshaft Housing . . . . . . . . . . . . . . . . . . . . . . 4A-14 Piston and Piston Ring Combinations . . . 4A-43
Powerhead Disassembly . . . . . . . . . . . . . . . . . 4A-18 Piston Installation . . . . . . . . . . . . . . . . . . . . 4A-44
Water Pressure Relief Valve Crankcase Cover Installation . . . . . . . . . . . 4A-47
Components . . . . . . . . . . . . . . . . . . . . . . . . . 4A-26 Assembly of Reed Blocks to
Torque Specifications . . . . . . . . . . . . . . . . . 4A-26 Intake Manifold . . . . . . . . . . . . . . . . . . . . . . . 4A-48
Cleaning and Inspection . . . . . . . . . . . . . . . . . . 4A-27 Assembly of Exhaust Divider Plate
Cylinder Block and Crankcase Cover . . . 4A-27 to Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-48
Special Service Information . . . . . . . . . . . . 4A-27 Reinstalling Engine Components . . . . . . . . . . 4A-51
Cylinder Bores . . . . . . . . . . . . . . . . . . . . . . . 4A-28 Throttle Lever and Shift Shaft . . . . . . . . . . . . . 4A-52
Pistons and Piston Rings . . . . . . . . . . . . . . 4A-29 Powerhead Installation on Driveshaft
Cylinder Heads and Exhaust Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4A-54
Divider Plate . . . . . . . . . . . . . . . . . . . . . . . . . 4A-31 Break-ln Procedure . . . . . . . . . . . . . . . . . . . . . . 4A-58

Powerhead Specifications

CYLINDER Type V-6 Cylinder, Two Cycle, Direct Injected

BLOCK Displacement 153 cu. in. (2508 cc) 60° Vee
STROKE Length (All Models) 2.65 in. (67.3 mm)
CYLINDER Diameter (Std) 3.501 in. (88.925 mm)
BORE Diameter 0.015 in. Oversize 3.516 in. (89.306 mm)
Taper/Out of Round/Wear Maximum 0.003 in. (0.076 mm)
Bore Type Cast Iron
PISTON Piston Type Aluminum
Diameter Standard 3.4925 in. ± .0005 in.
(88.7095 mm ± 0.0127 mm)
Diameter 0.015 in. Oversize 3.5075 in. ± 0.0005 in.
(89.0905 mm ± 0.0127 mm)
CRANKSHAFT Maximum Runout 0.006 in. (0.152 mm)

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PISTON 3.4925 in. ± .0005 in.

DIAMETER (88.7095 mm ± .0127 mm)
Dimension
Using a micrometer, measure dimension
“A” at Right “A” at location shown. Dimension “A”
Angle (90°) should be 3.4925 in. ± .0005 for a STAN-
to Piston Pin DARD size piston (new) Dimension “A”
will be 0.001 - 0.0015 less if coating is
17.78mm worn off piston (used)

REEDS Reed Stand 0pen (Max.) 0.020 in. (0.50 mm)

Special Tools
1. Lifting Eye 91-90455

2. Powerhead Stand 91-30591A1

3. Piston Ring Expander 91-24697

4. Lockring Removal Tool 91-52952A1

5. Piston Pin Tool 91-74607A1

6. Driver Head 91-55919

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7. Universal Puller Plate 91-37241

8. Snap Ring Pliers 91-24283

9. Lockring Installation Tool 91-77109A1

10. Piston Ring Compressor for 2.5 Litre (153 cu. in.) 91-818773

11. Compression Tester 91-29287

Powerhead Repair Stand

A powerhead repair stand may be purchased from:
Bob Kerr’s Marine Tool Co.
P.O. Box 1135
Winter Garden, FL 32787
Telephone: (305) 656-2089

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Cylinder Block and End Caps

9 Loctite PST Pipe Sealant

7
A 12 Loctite Master Gasket
9
14 2 Cycle Outboard Oil
48 21 33 Loctite 680 Retaining Compound
16
49 95 2-4-C with Teflon
17 95
11 32

14 31

9
27
12 95

6 28
46 45
14

29
44
5 43
38 39
30
47
40
41 9
42
41
33
4 8 11

13
2 22
33

12 9 3
11 24
15

1 26 25
21 18
19 9
B 11
9
PORT OIL FITTING 20 11 34
A ORIENTATION
TOP OF BLOCK 23
35 14
11
95 10
2 o’clock
HEAD
CRANK
SIDE 33
SIDE

37 36
BOTTOM OF BLOCK
A = TO AIR HANDLER
95 B = TO ON BOARD OIL TANK

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Cylinder Block and End Caps

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb-in lb-ft Nm
1 1 CYLINDER BLOCK
2 6 STUD–powerhead (1-3/4 IN.)
2 STUD–powerhead (5-1/2 IN.)
3
2 STUD–powerhead (6-3/4 IN.)
4 2 DOWEL PIN–locating
5 2 DOWEL PIN (BEARING RACE)
6 2 GASKET–sealing
7 1 PIPE PLUG (1/2-14) Drive Tight
8 1 CHECK VALVE
9 1 CHECK VALVE
10 1 TUBING (19 IN.)
11 10 STA STRAP
12 2 FITTING (STRAIGHT)(STARBOARD - TOP/BOTTOM)
13 1 FITTING (ELBOW) (STARBOARD - CENTER)
14 3 FITTING (ELBOW) (PORT)
2 TUBING (16 IN.) (TOP/BOTTOM)
15
1 TUBING (20 IN.) (CENTER)
16 3 TUBING (24-1/2 IN.)
17 1 CONDUIT (7 IN.)
18 1 FITTING
19 1 TUBING (11-1/2 IN.)
20 1 CONNECTOR
21 6 STA-STRAP
22 8 SCREW (3/8-16 x 3-1/4) 37 50
23 6 SCREW (.312-18 x 1-1/4) 15 20
24 1 CAP
25 1 ADJUSTING SCREW (1/4-20 x 1-3/4)
26 1 JAM NUT
27 1 UPPER END CAP
28 1 O-RING
29 1 ROLLER BEARING
30 1 BEARING RACE
31 1 OIL SEAL
32 4 SCREW (5/16-18 x 1) 17 23
33 1 LOWER END CAP
34 1 O-RING (3-1/4 IN. I.D.)
35 2 OIL SEAL
36 4 SCREW (1/4-20 x 3/4) 80 9
37 4 LOCKWASHER
38 1 BRACKET
39 1 TPI LEVER
40 3 SCREW -Bracket to crankcase 70 8
41 6 BUSHING
42 3 GROMMET
43 1 THROTTLE POSITION SENSOR (INSIDE)
44 1 SPACER
45 1 THROTTLE POSITION SENSOR (OUTSIDE)
46 3 SCREW -TPS to bracket (#10-32 x 2-3/4 IN.) 15 1.7
47 1 THROTTLE LINK
48 1 PLUG-Serial Number
49 1 STA-STRAP-Oil Lines

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Exhaust Manifold and Exhaust Plate

6 2
5 1

4 3
7 10

10

D 7

18
17
16
15 23
14 22
18 13 21
12 11 19 20
95

46
44 45
51
24
42 47
8 9
10
10 43

A
26
40
39
41 33
9

30
25
35
B 31 7 Loctite 271

34 37 9 Loctite PST Pipe Sealant

32
36 38 51 Loctite 222 Thread Locker
27
62
10 95 2-4-C With Teflon

C 29 28 141 Cyanacrylate Adhesive

A = TO FUEL COOLER WATER IN B = TO FUEL COOLER WATER OUT FITTING

C = TO LOWER PORT FUEL RAIL SIDE FITTING
D = TO AIR COMPRESSOR LOWER WATER INLET FITTING

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Exhaust Manifold and Exhaust Plate

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb-in lb-ft Nm
1 1 GASKET
2 1 DIVIDER PLATE
3 1 SEAL
4 17 SCREW (5/16-18 x 1-1/2 IN.) 13 18
5 2 SCREW (5/16-18 x 1 IN.) 13 18
6 1 STRAINER
7 1 HOSE (4-1/2 IN.)
8 1 ELBOW
9 1 HOSE (21-1/2 IN.)
10 5 STA-STRAP
11 1 COVER–relief valve
12 4 SCREW (5/16-18 x 1-1/4 IN.) 12.5 17
13 1 SCREW (10-16 x 3/4 IN.) 25 3
14 1 WASHER
15 1 DIAPHRAGM
16 1 WATER DEFLECTOR
17 1 PLATE
18 2 GASKET
19 1 SPRING
20 1 WASHER
21 1 POPPET
22 1 GROMMET
23 1 CARRIER
24 1 GASKET
25 1 EXHAUST PATE
26 2 DOWEL PIN
27 1 SEAL
28 1 BRACKET
29 8 SCREW (10-16 x 1/2 IN.) 80 9
30 1 FITTING (STRAIGHT)(BACK)
31 1 ELBOW (STARBOARD-TOP HOLE)
32 1 FITTING (STRAIGHT)(STARBOARD-BOTTOM HOLE)
33 1 GROMMET
34 1 GROMMET
35 1 HOSE (25 IN.)
36 1 HOSE
37 4 WASHER
38 6 NUT 23 31
39 1 BUSHING
40 1 SCREW (5/16-18 x 1-1/4 IN.) 45 61
41 1 SCREW (5/16-18 x 2-1/2 IN.) 45 61
42 3 SCREW (3/8-16 x 3-1/2 IN.) 23 31
43 1 FRONT BRACKET ASSEMBLY
44 4 SCREW (5/16-18 x 1/2 IN.) 17 23
45 4 WASHER
46 4 GROMMET
47 1 REAR BRACKET ASSEMBLY

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Cylinder Head
Water Fitting Orientation
Looking Down at Top of Block
10 9

12
15°
13

13 Back of Engine
11 13 14

9 13 3
8

A 1
9

6 4
5 7
2

14

16 15
6 Dielectric Grease
9 Loctite 567 PST Pipe Sealant
14 2 Cycle Premium Outboard Oil
A = TO STRAIGHT FITTING ON BACK OF EXHAUST PLATE

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Cylinder Head
TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb-in lb-ft Nm
1 CYLINDER HEAD (PORT)
1
1 CYLINDER HEAD (STARBOARD)
2 2 GASKET
30 lb-ft
3 24 BOLT (2 IN.) (40.7 Nm) then tight-
en additional 90°
4 4 DOWEL PIN
5 2 GASKET
6 2 COVER
7 2 THERMOSTAT (143 degrees)
8 4 SCREW (M6 x 25) 16.5 22.5
9 1 ELBOW (STARBOARD)
10 1 ELBOW (PORT)
11 1 HOSE (21-1/2 IN.)
12 1 HOSE (11-1/2 IN.)
13 5 STA-STRAP
14 1 TEMPERATURE SENSOR (STARBOARD)
15 1 RETAINER
16 1 SCREW (M8 x 12) 16.5 22.5

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Crankshaft, Pistons and Connecting Rods

14
11 95 12

9
10

16 95

14

14
95
12
13
8
7 95

95 8
15
95
14 6
1

3
4
5 95

14 2 Cycle Premium Outboard Oil

95 2-4-C with Teflon

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Crankshaft, Pistons and Connecting Rods

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb-in lb-ft Nm
1 1 CRANKSHAFT ASSEMBLY
2 1 BALL BEARING (LOWER)
3 1 RETAINING RING
4 1 CARRIER ASSEMBLY
5 1 SEAL
6 7 RING–sealing
7 2 ROLLER BEARING
8 2 RACE
3 PISTON (STARBOARD)
9
3 PISTON (PORT)
10 1 PISTON RING
11 12 LOCK RING
12 6 CONNECTING ROD ASSEMBLY
1st Torque: 15 lb-in
2nd Torque: 30 lb-ft
13 12 SCREW Turn Screw addition-
al 90° after 2nd
torque
14 12 WASHER
15 6 ROLLER BEARING ASSEMBLY
16 174 NEEDLE BEARING–piston end

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Torque Sequence
CRANKCASE COVER BOLTS (AND TORQUE SEQUENCE)
8 7

a 4
1

3 2
b

5 6
a - Add light oil to threads and bolt face: 8 Bolts (3/8 in. - 16 in.)
38 lb. ft. (51.5 Nm)
b - Bolts (5/16 in. - 18) 180 lb. in. (20 Nm)

EXHAUST DIVIDER PLATE BOLTS

Apply Loctite 271 to threads: 200 lb. in. (22.5 N·m)
19 18

10 15
13 14

6
5

3
1
2
4

7
8

11
12

16 17 56167

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CYLINDER HEAD BOLTS

Add light oil to threads and bolt face: 30 lb. ft. (41 N·m) then turn an additional
90°.

10 9

6 5
2 1

3 4
7 8

11 12 56168

AIR PLENUM/REED BLOCK ASSEMBLY PLATE BOLTS

100 lb. in. (11.3 N·m)
10 9

6
5
2 1

3 4

7 8

56160
11 12

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General Information
Powerhead Disassembly and Reassembly instructions are printed in a sequence that
should be followed to assure best results when removing or replacing powerhead compo-
nents. If complete disassembly is not necessary, start reassembly at point disassembly
was stopped. (Refer to Table of Contents, preceeding) Usually, complete disassembly of
powerhead will be required.
If major powerhead repairs are to be performed, remove powerhead from drive shaft
housing. Removal of powerhead is not required for 1) inspection of cylinder walls and pis-
tons (refer to Powerhead Removal and Disassembly, following, and remove cylinder
heads and exhaust cover), 2) minor repairs on components, such as ignition system, fuel
injection, reed blocks and cylinder heads and checking operation of thermostats.

Powerhead Removal from Driveshaft Housing

1. Disconnect battery cables from battery terminals.
2. Disconnect fuel tank hose from outboard.
3. Remove top cowling.
4. Remove two screws which secure remote control harness retainer and remove re-
tainer.
a

b
52188

a - Screws
b - Retainer

5. Disconnect remote oil tank hose connector.

6. Disconnect remote control harness from powerhead harness connector and wires as
shown.

BLU/WHT BLU/WHT
GRN/WHT GRN/WHT a
TAN
BRN/WHT

a - Power Trim Connections

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7. Remove sta-strap which secures tell-tale hose to fitting on lower cowl and remove
hose from fitting.

56141

a - Tell-tale Hose

8. Disconnect warning gauge harness.

1 6

2 3 45

a
b
c
d

a
b
c
d
a - TAN/BLACK
b - TAN/WHITE
c - PINK/LT. BLUE to PINK/LT. BLUE
d - ORANGE
e - Sta-Straps

9. Remove BLUE and GREEN trim harness leads from trim solenoids.

a
a - Trim Solenoids

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10. Slide outboard shift lever into neutral position.

11. Remove throttle cable.
12. Remove locknut that secures the shift cable latch assembly and remove latch, flat
washer, nylon wear plate, spring and shift cable from control cable anchor bracket.
13. Disconnect input fuel line.

b
d
a - Throttle Cable
b - Shift Cable
c - Hose Clamp
d - Fuel Line

14. Remove 4 bolts securing bottom cowl halves and remove bottom cowling.

52352

55970
a

a
55932

a - Bolt

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15. Remove fuel cooler inlet and outlet water hoses from fittings on exhaust adaptor plate
and poppet valve cover. Remove excess air hose (from port fuel rail) from fitting on
exhaust adaptor plate.
16. Remove thermostat cover hose from exhaust adaptor plate.

b
d 56158

c 56159
a - Fuel Cooler Outlet Water Hose
b - Fuel Cooler Inlet Water Hose
c - Air Hose
d - Thermostat Cover Hose

17. Remove 10 nuts and washers (five each side) from powerhead base.
18. Remove plastic cap from center of flywheel and install lifting eye into flywheel at least
five full turns. Using a hoist, lift powerhead assembly from driveshaft housing.

a a a

a
a
51846

56162
a - Nuts and Washers (5 Each Side)
b - Lifting Eye (91-90455)

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REMOVING ENGINE COMPONENTS

Remove the following engine components:
Section 2 Starter Motor
Starter Motor
*Electronic Control Module
*Ignition Coil
*Starter Solenoid
Alternator
Flywheel
Section 3
Direct Fuel Injection
Fuel Pump
On-Board Oil Tank
Oil Pump
Section 7
Shift Cable Latch Assembly
Control Cable Anchor Bracket
*All ignition and electrical components should remain attached to electrical plate.
Plate with components can be removed as an assembly.

Powerhead Disassembly
1. Place powerhead in repair stand or on a bench.
2. Remove thermostat covers, thermostats and gaskets.
3. Remove cylinder heads from engine block.

b c

e d
56163 f 56165
a - Thermostat Cover
b - Thermostat
c - Gasket
d - Cylinder Head
e - Gasket
f - Engine Block

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4. Remove exhaust manifold cover and seal.

5. Referring to Section 3B, remove air plenum/reed block/adaptor plate assembly from
cylinder block.
c
d

b
a

56166
a - Exhaust Manifold Cover
b - Seal
c - Gasket
d - Air Plenum/Reed Block/Adaptor Plate Assembly

6. Inspect reeds as outlined in Cleaning and Inspection.

56169

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7. Remove bolts from end caps.

Upper End Cap

51854
a - Crankcase Attaching End Cap Bolts

Lower End Cap

51849
a - Crankcase Attaching End Cap Bolts

1. Remove bolts which secure crankcase cover to cylinder block.

2. Pry crankcase cover off cylinder block using pry bars in locations shown.

b a

a
51845
a - Pry Points
b - Crankcase Cover

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CRANKCASE COVER REMOVED

51848

1. Use Powerhead Stand (91-30591A1) for rotating crankshaft to desired position for re-
moval of connecting rods.
2. Using an awl or electric pencil, scribe the cylinder identification number on each con-
necting rod as shown. Reassemble connecting rods in same cylinder.

ÄÄ
ÄÄ

51849
3. Use a 5/16 in. 12 point socket to remove connecting rod bolts, then remove rod cap,
roller bearings and bearing cage from connecting rod.
a

51850
a - Connecting Rod Bolts

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4. Push piston out of cylinder block.

5. After removal, reassemble each piston and connecting rod assembly.

CAUTION
Each connecting rod and end cap are a matched machined set and must never
be mismatched.
6. Inspect pistons as outlined in Cleaning and Inspection, following.
7. Use Piston Ring Expander (91-24697) to remove piston rings. Always install new pis-
ton rings.

56155
56153
8. Using an awl, scribe identification number of connecting rod on inside of piston. Reas-
semble piston on same connecting rod.

9. Using tool (91-52952A1), remove piston pin lockrings from both ends of piston pin.
Never re-use piston pin lockrings.

a
b

51083
56154

a - Scribe Identification Number

b - Lockring

IMPORTANT: Warming the piston dome using a torch lamp will ease removal and
installation of piston pin.

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10. Support piston and tap out piston pin using service tool as shown.
11. Remove piston pin needle bearings (29 per piston) and locating washers (2 per pis-
ton) as shown.
IMPORTANT: We recommend that you use new needle bearings at reassembly for
lasting repair. However, if needle bearings must be re-used, keep each set of bear-
ings identified for reassembly on same connecting rod.

b
a

c
51853
51088
a - Piston Pin
b - Piston Pin Tool (91-76159A1)
c - Needle Bearing Locating Washers

12. Remove upper end cap and lower end cap from crankshaft.
13. Remove and discard O-ring seals from each end cap.
14. Remove oil seals from end of each end cap by driving seal out with a punch and ham-
mer.
15. Inspect roller bearing in upper end cap as outlined in Cleaning and Inspection.
NOTE: If roller bearing is damaged, replace upper end cap and roller bearings as an
assembly.
b a

51848 c
51853
a - Upper End Cap
b - Lower End Cap
c - O-Ring
d - Seal

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16. Remove crankshaft and place in powerhead stand as shown.

IMPORTANT: DO NOT remove crankshaft sealing rings from crankshaft, unless re-
placement of one or more sealing rings is necessary. Usually, crankshaft sealing
rings do not require replacement, unless broken.

CAUTION
Safety glasses should be worn when removing or installing crankshaft sealing
rings.
17. Remove retaining ring as shown.

51850

a - Sealing Rings
b - Retaining Ring

18. Remove bearing race halves and roller bearings from crankshaft.
IMPORTANT: Keep same bearing races and roller bearings together.

51850
a - Bearing Race Halves
b - Roller Bearings

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19. Inspect crankshaft ball bearing as outlined in Cleaning and Inspection, following.
IMPORTANT: DO NOT remove crankshaft ball bearing, unless replacement is re-
quired.
20. Remove lower ball bearing from crankshaft as follows:
a. Remove retaining ring using a pair of snap ring pliers.

a b

51854
a - Crankshaft Ball Bearing
b - Pliers
c - Retaining Ring

b. Press crankshaft out of lower ball bearing as shown.

b
c

51081
a - Press
b - Powerhead Stand (91-30591A1)
c - Crankshaft Ball Bearing
d - Universal Puller Plate (91-37241)

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Water Pressure Relief Valve Components

1. If necessary, remove water pressure relief valve components as shown.

12
11
10
13
9
3
4
6
5
7
3 8
1
2

a
50803
1 - Cover
2 - Bolt
3 - Gasket
4 - Relief Valve Plate
5 - Diaphragm
6 - Water Deflector
7 - Washer
8 - Screw
9 - Spring
10 - Poppet Valve
11 - Grommet
12 - Carrier
13 - Washer

Torque Specifications
a 150 lb. in. (17 Nm)

b 25 lb. in. (3 Nm)

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Cleaning and Inspection

Cylinder Block and Crankcase Cover
IMPORTANT: Crankcase cover and cylinder block are a matched, line-bored as-
sembly and never should be mismatched by using a different crankcase cover or
cylinder block.

CAUTION
If crankcase cover or cylinder block is to be submerged in a very strong cleaning
solution, it will be necessary to remove the crankcase cover/cylinder block bleed
system from crankcase cover/cylinder block to prevent damage to hoses and
check valves.
1. Thoroughly clean cylinder block and crankcase cover. Be sure that all sealant and old
gaskets are removed from matching surfaces. Be sure that carbon deposits are re-
moved from exhaust ports.
2. Inspect cylinder block and crankcase cover for cracks or fractures.
3. Check gasket surfaces for nicks, deep grooves, cracks and distortion that could cause
compression leakages.
4. Check all water and oil passages in cylinder block and crankcase cover to be sure that
they are not obstructed and that plugs are in place and tight.
Special Service Information
Grooves in Cylinder Block Caused By Crankshaft Sealing Rings
Grooves in cylinder block caused by crankshaft sealing rings are not a problem, except
if installing a new crankshaft and the new sealing rings on crankshaft do not line up with
existing grooves in cylinder block. If installing a new crankshaft, refer to crankshaft instal-
lation, Powerhead Reassembly section to determine if powerhead can be used.

90-855347R02 NOVEMBER 2002 Page 4A-27

POWERHEAD

Cylinder Bores
1. Inspect cylinder bores for scoring, scuffing or a transfer of aluminum from piston to
cylinder wall. Scoring or scuffing, if NOT TOO SEVERE, can normally be removed by
honing. If a transfer of aluminum has occurred, an acidic solution such as “TIDY
BOWL CLEANER” should be applied to the areas of the cylinder bore where transfer
of aluminum has occurred. After the acidic solution has removed the transferred alu-
minum, thoroughly flush the cylinder bore to remove any remaining acid. Cylinder
walls may now be honed to remove any glaze and to aid in the seating of new piston
rings.
HONING PROCEDURE
a. When cylinders are to be honed, follow the hone manufacturer’s recommenda-
tions for use of the hone and cleaning and lubrication during honing.
b. For best results, a continuous flow of honing oil should be pumped into the work
area. If pumping oil is not practical, use an oil can. Apply oil generously and fre-
quently on both stones and work area.

CAUTION
When honing cylinder block, remove hone frequently and check condition of cyl-
inder walls. DO NOT hone any more than absolutely necessary, as hone can re-
move cylinder wall material rapidly.
c. Start stroking at smallest diameter. Maintain firm stone pressure against cylinder
wall to assure fast stock removal and accurate results.
d. Localize stroking in the smallest diameter until drill speed is constant throughout
length of bore. Expand stones, as necessary, to compensate for stock removal
and stone wear. Stroke at a rate of 30 complete cycles per minute to produce best
cross-hatch pattern. Use honing oil generously.
e. Thoroughly clean cylinder bores with hot water and detergent. Scrub well with a
stiff bristle brush and rinse thoroughly with hot water. A good cleaning is essential.
If any of the abrasive material is allowed to remain in the cylinder bore, it will cause
rapid wear of new piston rings and cylinder bore in addition to bearings. After
cleaning, bores should be swabbed several times with engine oil and a clean
cloth, then wiped with a clean, dry cloth. Cylinders SHOULD NOT be cleaned with
kerosene or gasoline. Clean remainder of cylinder block to remove excess materi-
al spread during honing operation.
2. Hone all cylinder walls just enough to de-glaze walls.

Page 4A-28 90-855347R02 NOVEMBER 2002

 POWERHEAD

3. Measure cylinder bore diameter (with a snap gauge micrometer) of each cylinder, as
shown below. Check for tapered, out-of-round (egg-shaped) and oversize bore.

51846
135/150 Models
Models Cylinder Block Finish Hone
Standard Piston Bore 3.501 in. (88.93mm)
.015 in. (0.381mm) Oversize Piston Bore 3.516 in. (89.31mm)
4. If a cylinder bore is tapered, out-of-round or worn more than 0.003 in. (0.076mm) from
standard Cylinder Block Finish Hone diameter (refer to chart), it will be necessary to
re-bore that cylinder to 0.015 in. (0.381mm) oversize or re-sleeve and install oversize
piston and piston rings during reassembly.
NOTE: The weight of an oversize piston is approximately the same as a standard size
piston; therefore, it is not necessary to re-bore all cylinders in a block just because one
cylinder requires re-boring.
5. After honing and thoroughly cleaning cylinder bores, apply light oil to cylinder walls
to prevent rusting.
Pistons and Piston Rings
IMPORTANT: If engine was submerged while engine was running, piston pin and/or
connecting rod may be bent. If piston pin is bent, piston must be replaced. (Piston
pins are not sold separately because of matched fit into piston.) If piston pin is
bent, connecting rod must be checked for straightness (refer to Connecting Rods,
following, for checking straightness).
1. Inspect pistons for scoring and excessive piston skirt wear.
2. Check tightness of piston ring locating pins. Locating pins must be tight.
3. Thoroughly clean pistons. Carefully remove carbon deposits from pistons, with a soft
wire brush or carbon remove solution. Do not burr or round off machined edges.
Inspect piston ring grooves for wear and carbon accumulation. If necessary, scrape car-
bon from piston ring grooves being careful not to scratch sides of grooves. Refer to
procedure following for cleaning piston ring grooves.

90-855347R02 NOVEMBER 2002 Page 4A-29

POWERHEAD

CLEANING PISTON RING GROOVES

Keystone (tapered) ring grooves

CAUTION
Care must be taken not to scratch the side surfaces of the ring groove. Scratching
the side surface of the ring groove will damage the ring groove.
1. Use a bristle brush and carbon remover solution to remove carbon from side surfaces.
2. A tool can be made for cleaning the inner diameter of the tapered ring grooves. The
tool can be made from a broken tapered piston ring with the side taper removed to
enable the inside edge of the ring to reach the inner diameter of the groove. Carefully
scrape carbon from inner diameter of ring grooves. Care must be taken not to damage
the grooves by scratching the side surfaces of the grooves.
Piston with two half keystone (half tapered) rings (135/150 Models)

Enlarged View of
Piston Ring Grooves

MEASURING PISTON ROUNDNESS

Piston has a barrel profile shape and is not a true diameter.
Standard 135/150 Models - 153 cu. in. (2508 cc)
1. Using a micrometer, measure dimension “A” at location shown. Dimension “A” should
be as indicated in chart following.

Piston Dimension “A”

Standard Piston 3.4925 in. ± 0.0005 in.
0.015 in. Oversize Piston 3.5075 in. ± 0.0005 in.

2. Using a micrometer, measure dimension “B” at location shown. Dimension “B” should
be within 0.008 in. of dimension “A.”

a
0.700 in.
(17.78mm)

b
a - Dimension “A” at RIGHT Angle (90°) to Piston Pin
b - Dimension “B” (in line with Piston Pin)

Page 4A-30 90-855347R02 NOVEMBER 2002

 POWERHEAD

Cylinder Heads and Exhaust Divider Plate

1. Inspect internal surface of cylinder heads for possible damage (as a result of piston
or foreign material striking cylinder heads).
IMPORTANT: Cylinder head warpage should not exceed 0.004 in. (0.1 mm) over the
ENTIRE length of the cylinder head. If measured warpage, as determined on a sur-
face block, exceeds 0.004 in. (0.1 mm) or a discontinuity of up to 0.004 in. (0.1 mm)
exists in a narrow portion of the cylinder head’s surface length, then the cylinder
head may be re-surfaced up to 0.010 in. (0.25 mm).
2. Replace cylinder heads as necessary.
3. Thoroughly clean gasket surfaces of exhaust divider plate.
4. Inspect exhaust divider plate for deep grooves, cracks or distortion that could cause
leakage. Replace parts as necessary.
Crankshaft
1. Inspect crankshaft to drive shaft splines for wear. (Replace crankshaft, if necessary.)
2. Check crankshaft for straightness. Maximum runout is 0.006 in. (0.152 mm). (Replace
as necessary.)
3. Inspect crankshaft oil seal surfaces. Sealing surfaces must not be grooved, pitted or
scratched. (Replace as necessary.)
4. Check all crankshaft bearing surfaces for rust, water marks, chatter marks, uneven
wear and/or overheating. (Refer to Connecting Rods.)
5. If necessary, clean crankshaft surfaces with crocus cloth.

a b

c
c

51847
a - Crankshaft Journals
b - Crocus Cloth
c - Work Cloth Back-and-Forth

WARNING
DO NOT spin-dry crankshaft ball bearing with compressed air.
6. Thoroughly clean (with solvent) and dry crankshaft and crankshaft ball bearing. Re-
check surfaces of crankshaft. Replace crankshaft, if surfaces cannot be properly
cleaned up. If crankshaft will be re-used, lubricate surfaces of crankshaft with light oil
to prevent rust. DO NOT lubricate crankshaft ball bearing at this time.

90-855347R02 NOVEMBER 2002 Page 4A-31

POWERHEAD

Crankshaft (and End Cap) Bearings

1. After cleaning crankshaft, grasp outer race of crankshaft ball bearing (installed on low-
er end of crankshaft) and attempt to work race back-and-forth. There should not be
excessive play.
2. Lubricate ball bearing with light oil. Rotate outer bearing race. Bearing should have
smooth action and no rust stains. If ball bearing sounds or feels rough or has catches,
remove and discard bearing. (Refer to Powerhead Removal and Disassembly -
Crankshaft Removal and Disassembly.)

Lower Ball Bearing

3. Thoroughly clean (with solvent) and dry crankshaft center main roller bearings. Lubri-
cate bearings with 2-Cycle Premium Outboard Oil.

CAUTION
DO NOT intermix halves of upper and lower crankshaft center main roller bear-
ings. Replace bearings in pairs only.
4. Thoroughly inspect center main roller bearings. Replace bearings if they are rusted,
fractured, worn, galled or badly discolored.

Center Main Roller Bearing

5. Clean (with solvent) and dry crankshaft roller bearing that is installed in upper end cap.
Lubricate bearing with light oil.
6. Thoroughly inspect upper end cap roller bearing. If roller bearing is rusted, fractured,
worn, galled, badly discolored or loose inside of end cap replace end cap and roller
bearing as an assembly.

Upper Roller Bearing

Page 4A-32 90-855347R02 NOVEMBER 2002

 POWERHEAD

Reed Block Assembly

IMPORTANT: DO NOT remove reeds from reed blocks, unless replacement is nec-
essary. DO NOT turn used reeds over for re-use. Replace reeds in sets only.
1. Thoroughly clean gasket surfaces of reed blocks and reed block housing. Check for deep
grooves, cracks and distortion that may cause leakage. Replace parts as necessary.
2. Inspect reed block neoprene surface for wear, cuts or abrasions. Replace reed blocks
as required.
3. Check for chipped and broken reeds.

051
020

56161
Allowable reed opening is 0.020 in. (0.51 mm) or less. Replace reeds if either reed is
standing open more than 0.020 in. (0.51 mm).
End Bearing Bleed System
1. Check rubber bleed hoses. Replace any hose that is cracked, cut or deteriorating.
2. Check operation of lower end cap check valve. If valve is working properly, air can be
drawn through check valve one way only. If air can pass through a check valve both
ways, valve is not working properly and must be replaced.
Connecting Rods
1. Check connecting rods for alignment by placing rods on a surface plate. If light can
be seen under any portion of machined surfaces, if rod has a slight wobble on plate,
or if a 0.002 in. (0.051 mm) feeler gauge can be inserted between any machined sur-
face and surface plate, rod is bent and must be discarded.
2. Overheating: Overheating is visible as a bluish bearing surface color that is caused
by inadequate lubrication or excessive RPM.
3. Rust: Rust formation on bearing surfaces causes uneven pitting of surfaces.

a 51853

a - Pitting

90-855347R02 NOVEMBER 2002 Page 4A-33

POWERHEAD

4. Water Marks: When bearing surfaces are subjected to water contamination, a bear-
ing surface etching occurs. This etching resembles the size of the bearing.

51853

5. Spalling: Spalling is the loss of bearing surface, and it resembles flaking or chipping.
Spalling will be most evident on the thrust portion of the connecting rod in line with the
I-beam. General bearing surface deterioration could be caused by or accelerated by
improper lubrication.

a 51853
a - Spalling

6. Chatter Marks: Chatter marks are the result of a combination of low speed - low load
- cold water temperature operation, aggravated by inadequate lubrication and/or im-
proper fuel. Under these conditions, the crankshaft journal is hammered by the con-
necting rod. As ignition occurs in the cylinder, the piston pushes the connecting rod
with tremendous force, and this force is transferred to the connecting rod journal.
Since there is little or no load on the crankshaft, it bounces away from the connecting
rod. The crankshaft then remains immobile for a split second until the piston travel
causes the connecting rod to catch up to the waiting crankshaft journal, then hammers
it. The repetition of this action causes a rough bearing surfaces which resembles a
tiny washboard. In some instances, the connecting rod crank pin bore becomes highly
polished. During operation, the engine will emit a whirr and/or chirp sound when it is
accelerated rapidly from idle speed to approximately 1500 RPM, then quickly re-
turned to idle. If the preceding conditions are found, replace both the crankshaft and
connecting rods.

a
a 51853
a - Chatter Marks Between Arrows

Page 4A-34 90-855347R02 NOVEMBER 2002

 POWERHEAD

7. Uneven Wear: Uneven wear could be caused by a bent connecting rod.

aa 51853

a - Uneven Wear Between Arrows

8. If necessary, clean connecting rod bearing surfaces, as follows:

a. Be sure that etched marks on connecting rod (crankshaft end) are perfectly
aligned with etched marks on connecting rod cap. Tighten connecting rod cap at-
taching bolts securely.

CAUTION
Crocus cloth MUST BE USED to clean bearing surface at crankshaft end of con-
necting rod. DO NOT use any other type of abrasive cloth.
b. Clean CRANKSHAFT END of connecting rod by using CROCUS CLOTH
placed in a slotted 3/8 in. (9.5 mm) diameter shaft, as shown. Chuck shaft in a drill
press and operation press at high speed while keeping connecting rod at a 90°
angle to slotted shaft.
IMPORTANT: Clean connecting rod just enough to clean up bearing surfaces. DO
NOT continue to clean after marks are removed from bearing surfaces.

51083

c. Clean PISTON PIN END of connecting rod, using same method as in Step “b”,
preceding, but using 320 grit carborundum cloth instead of crocus cloth.
d. Thoroughly wash connecting rods to remove abrasive grit. Recheck bearing sur-
faces of connecting rods. Replace any connecting rods that cannot be properly
cleaned up. Lubricate bearing surfaces of connecting rods (which will be re-used)
with light oil to prevent rust.

90-855347R02 NOVEMBER 2002 Page 4A-35

POWERHEAD

Thermostats
1. Inspect thermostat covers and cylinder head covers (thermostat opening) for cracks
and corrosion damage that could cause leakage. Replace parts as necessary.
2. Remove and discard gasket from each thermostat.
3. Wash thermostats with clean water.
4. Using a thermostat tester, similar to the one shown, test each thermostat as follows:
a. Open thermostat valve, then insert a thread between valve and thermostat body.
Allow valve to close against thread.
b. Suspend thermostat (from thread) and thermometer inside tester so that neither
touches the container. Bottom of thermometer must be even with bottom of ther-
mostat to obtain correct temperature of thermostat opening.
c. Fill thermostat tester with water to cover thermostat.
d. Plug tester into electrical outlet.
e. Observe temperature at which thermostat begins to open. (Thermostat will drop
off thread, that was installed in Step “a”, when it starts to open.) Thermostat must
begin to open when temperature reaches 140°-145° F (60°-63° C).
f. Continue to heat water until thermostat is completely open.
g. Unplug thermostat tester.
h. Replace thermostat, if it fails to open at the specified temperature, or if it does not
fully open.
NOTE: BE SURE that water in thermostat tester is allowed to cool sufficiently [below 130°
F (56° C)] before testing the other thermostat.

51087

Page 4A-36 90-855347R02 NOVEMBER 2002

 POWERHEAD

Powerhead Reassembly and Installation

General
Before proceeding with powerhead reassembly, be sure that all parts to be re-used have
been carefully cleaned and thoroughly inspected, as outlined in Cleaning and Inspection,
preceding. Parts, which have not been properly cleaned (or which are questionable), can
severely damage an otherwise perfectly good powerhead within the first few minutes of
operation. All new powerhead gaskets MUST BE installed during reassembly.
During reassembly, lubricate parts with 2-Cycle Premium Outboard Oil whenever light
oil is specified. Part numbers of lubricants, sealers and locking compounds and tools are
listed in Section 1A - Mercury/Quicksilver Lubricants and Sealants.
A torque wrench is essential for correct reassembly of powerhead. DO NOT attempt to
reassemble powerhead without using a torque wrench. Attaching bolts for covers, hous-
ings and cylinder heads MUST BE torqued by tightening bolts in 3 progressive steps (fol-
lowing specified torque sequence) until specified torque is reached (see Example follow-
ing).
EXAMPLE: If cylinder head attaching bolts require a torque of 30 Ib. ft. (41 N·m), a) tighten
all bolts to 10 Ib. ft. (13.5 Nm), following specified torque sequence, b) tighten all bolts
to 20 Ib. ft. (27 Nm), following torque sequence, then finally c) tighten all bolts to 30 Ib.
ft. (41 Nm), following torque sequence.
1. If removed, press lower crankshaft ball bearing onto crankshaft as shown. Be sure
bearing is pressed firmly against counterweight.
2. Reinstall retaining ring using a suitable pair of Snap Ring Pliers.

e
d

a b

51854

51852
a - Crankshaft
b - Crankshaft Ball Bearing
c - Suitable Mandrel
d - Press
e - Retaining Ring

90-855347R02 NOVEMBER 2002 Page 4A-37

POWERHEAD

3. If removed, spread new crankshaft sealing rings just enough to slide over crankshaft
journal.
4. Use Piston Ring Expander (91-24697) and install crankshaft sealing rings into
groove.

51849
51854
a - Crankshaft Sealing Rings

5. Lubricate center main crankshaft roller bearings and races with light oil.

14

a b 51854
14 2 Cycle Outboard Oil

a - Install so LARGER of the 3 holes is toward DRIVE SHAFT end of crankshaft

b - Verify retaining ring bridges the separating lines of the bearing race

Page 4A-38 90-855347R02 NOVEMBER 2002

 POWERHEAD

6. Place center main crankshaft roller bearings on upper and lower main bearing jour-
nals as shown.
7. Install center main bearing races as shown.
8. Secure center main bearing races together with retaining rings. Make sure retaining
ring bridges the separating lines of the bearing race.

FLYWHEEL END

51850
DRIVE SHAFT END
51847
a - Center Main Bearing Races

9. Install oil seals into lower end cap as follows:

a. Apply a thin bead of Loctite 271 to outer diameter on 2 lower end cap oil seals.
b. Using driver head (91-55919) press one oil seal (lip facing down) into lower end
cap until firmly seated. Remove any excess Loctite.
c. Press second oil seal (lip facing down) until firmly seated on first oil seal. Remove
any excess Loctite.
d. Lubricate oil seal lips with 2-4-C with Teflon.
e. Lubricate O-ring seal surface on end cap with 2 cycle oil. Install O-ring over lower
end cap.

7
a
95 b
7 Loctite 271 51849
14
14 2 Cycle Outboard Oil
95 2-4-C With Teflon

a - Oil Seal
b - O-ring

90-855347R02 NOVEMBER 2002 Page 4A-39

POWERHEAD

10. Install oil seal into upper end cap as follows:

a. Apply a thin bead of Loctite 271 to outer diameter of upper end cap oil seal.
b. Use a suitable mandrel, press oil seal into upper end cap (lip facing down) until
bottomed out on lip of end cap. Remove any excess Loctite.
c. Lubricate oil seal lip with 2-4-C with Teflon.
d. Lubricate O-ring seal surface on end cap with 2-4-C with Teflon. Install O-ring on
end cap.

95
a

95

7 Loctite 271
95 2-4-C With Teflon ac 51849

a - Oil Seal
b - Lip of End Cap
c - O-ring

Crankshaft Installation
SPECIAL INFORMATION
Installing A New Crankshaft Assembly Into Cylinder Block
Check the crankshaft sealing ring mating surfaces in the cylinder block and crankcase
cover for wear grooves that were caused by the crankshaft sealing rings from the previous
crankshaft. If wear grooves are present, the sealing rings on the new crankshaft will have
to fit into the grooves without binding the crankshaft.
Before installing crankshaft, remove any burrs that may exist on groove edges.
Lubricate sealing rings with light oil and install new crankshaft as instructed.
Install upper and lower end caps and then inspect fit between sealing rings and grooves.
Temporarily install crankcase cover and rotate crankshaft several times to check if sealing
rings are binding against crankshaft. (You will feel a drag on the crankshaft.) If sealing
rings are binding, recheck grooves for burrs. If this does not correct the problem, it is rec-
ommended that the cylinder block be replaced.

Page 4A-40 90-855347R02 NOVEMBER 2002

 POWERHEAD

Install crankshaft as follows:

1. Lubricate crankshaft sealing rings with light oil.
2. Check cylinder block to be sure that dowel pins are in place.

51848
a - Dowel Pins

3. Position all crankshaft seal ring gaps straight up.

4. Align hole in each center main bearing race with dowel pin.
5. Gently push crankshaft down into position making sure that the dowel pins are lined
up with the holes in center main bearings and crankshaft seal rings are in place.

6. Lubricate crankshaft ends (oil seal areas) with light oil, then install upper and lower
end caps (a and b). Secure end caps to cylinder block with attaching bolts. DO NOT
tighten end cap bolts at this time.
b
c
14 14

51848
a 51848
14 2 Cycle Outboard Oil
a - Dowel Pin
b - Upper End Cap
c - Lower End Cap

90-855347R02 NOVEMBER 2002 Page 4A-41

POWERHEAD

Piston and Connecting Rod Reassembly

1. Place needle bearings on a clean piece of paper and lubricate with 2-4-C with Teflon.
NOTE: There are 29 needle bearings per piston.
2. Place sleeve which is part of piston pin tool assembly into connecting rod and install
needle bearings around sleeve as shown.
3. Place locating washers on connecting rod.
IMPORTANT: Position connecting rod part number facing towards flywheel.
Carefully position piston over end of rod. Make sure locating washers remain in place.

a
b

51851

b 51851
a - Sleeve (Part of Tool Assembly 91-74607A1)
b - Locating Washers

4. Insert piston pin tool and push sleeve out of piston. Keep piston pin tool in piston.
5. Use a mallet and tap piston pin into piston and push piston pin tool out.

c
a b

51080
51086
a - Piston Pin Tool (91-74607A1)
b - Sleeve
c - Piston Pin
d - Piston Pin Tool

Page 4A-42 90-855347R02 NOVEMBER 2002

 POWERHEAD

6. Install new piston pin lockrings (one each end of piston pin) with Lockring Installation
Tool.
7. Make sure lockrings are properly seated in piston grooves.

51086
51086

a - Lockring Installation Tool (91-77109A1)

b - Lockring

Piston and Piston Ring Combinations

153 CU. IN. (2508 cc) MODELS
All 153 cu. in. (2508 cc) models have two half keystone (half tapered) rings.
Pistons with two half keystone (half tapered) rings.

0.056 in. (1.4 mm)

a b

0.056 in. (1.4 mm)

a - Half Keystone (half tapered) Piston Ring

b - Enlarged View of Piston Ring Grooves

90-855347R02 NOVEMBER 2002 Page 4A-43

POWERHEAD

Piston Installation
1. Before installing new piston rings, check gap between ring ends by placing each ring
in its respective cylinder, then pushing ring about 1/2 in. (12.7 mm) into cylinder using
piston to assure proper position.
2. Check end gap of each new piston ring with a feeler gauge. End gap must be within
0.010 in. to 0.018 in. (0.25 mm to 0.45 mm). If end gap is greater, check other piston
rings in cylinder bore, until rings (within tolerance) are found.
IMPORTANT: Piston ring side with dot or letter must be facing up.

a
b

f
c d

51852
a - Piston Ring
b - Dots (Faces Up)
c - Feeler Gauge
d - Ring End Gap
e - Dot or Letter
f - Piston Ring

3. Use Piston Ring Expander and install piston rings (dot side up) on each piston. Spread
rings just enough to slip over piston.
4. Check piston rings to be sure that they fit freely in ring groove.
5. Lubricate piston, rings and cylinder wall with 2-Cycle Premium Outboard Oil.

aa

bb

56155
a - Piston Ring Expander (91-24697)
b - Dot Side “Up” on Piston Ring

Page 4A-44 90-855347R02 NOVEMBER 2002

 POWERHEAD

6. Rotate each piston ring so end of ring is aligned with locating pin as shown.
7. Install Piston Ring Compressor.
8. Remove screws and connecting rod cap from piston rod assembly being installed.
IMPORTANT: Piston must be correctly installed and positioned as shown.
Pistons marked with the word “UP” and with the letter “P” or “S” on top of piston.
Pistons with the letter “P” must be installed in the port side of engine and the word “UP”
facing toward top of engine.
Pistons with the letter “S” must be installed in the starboard side of engine and the word
“UP” toward top of engine.
9. Coat cylinder bore with 2-cycle Premium Outboard Oil. Match piston assembly with
cylinder it was removed from, and position piston as described below. Push piston into
cylinder.

14
UP UP
CYL 2 CYL 1
P S

UP UP
CYL 4 CYL 3
P S

UP UP
CYL 6 CYL 5
P S
56156
14 2 Cycle Outboard Oil
10. Apply 2-4-C with Teflon to bearing surface of connecting rod and install bearing as-
sembly, as shown.
11. Place connecting rod cap on connecting rod. Apply light oil to threads and face of con-
necting rod bolts. Thread connecting rod bolts finger-tight while checking for correct
alignment of the rod cap as shown.
IMPORTANT: Connecting rod and connecting rod caps are matched halves. Do not
torque screws before completing the following procedure.
• Run a pencil lightly over ground area.
• If pencil stops at fracture point, loosen bolts, retighten, and check again.
NOTE: If you still feel the fracture point, discard the rod.

90-855347R02 NOVEMBER 2002 Page 4A-45

POWERHEAD

12. Tighten connecting rod bolts (using a 5/16 in. - 12 point socket). First torque to 15 lb.
in. (1.7 Nm) then 30 lb. ft. (41 Nm). Turn each bolt an additional 90° after 2nd torque
is attained. Recheck alignment between rod cap and rod as shown.
aa
aa
95

51850
95 2-4-C With Teflon
a - Connecting Rod Screws

13. Rotate crankshaft several times (using powerhead stand) to assure free operation
(no binds and catching).
CONNECTING ROD CAP ALIGNMENT
Check each connecting rod cap for correct alignment. If not aligned, a ridge can be seen
or felt at the separating line as shown below. Correct any misalignment.
End View End View
Side View End View Incorrect- Incorrect-Cap
Side View Incorrect-Cap Correct Not Aligned on Backwards
Correct on Backwards

Ä ÄÄ ÄÄ
Ä
Ä ÄÄ
ÄÄ ÄÄ
Ä ÄÄ ÄÄ
14. Verify that no piston rings were broken during installation by pressing in on each piston
ring through exhaust port using a screwdriver. If no spring tension exists (ring fails to
return to position), it’s likely ring is broken and must be replaced.

51852
a - Screwdriver

Page 4A-46 90-855347R02 NOVEMBER 2002

 POWERHEAD

Crankcase Cover Installation

1. Thoroughly remove all oil from mating surfaces of crankcase cover and cylinder block
with Loctite 7649 Primer N.
2. Install gasket strips into grooves in crankcase cover. Trim end of each gasket strip
flush with edge of cover as shown.

a b

51852
a - Gasket Strips
b - Edge of Cover

3. Apply a thin, even coat of Loctite Master Gasket on mating surfaces of crankcase cov-
er and cylinder block.
4. Place crankcase cover in position on cylinder block. Turn the 8 center main bolts in
a little at a time, (following torque sequence) compressing crankshaft seal rings until
crankshaft cover has been drawn down to cylinder block. Tighten eight bolts evenly
in three progressive steps (following torque sequence).
5. Install remaining crankcase cover flange bolts.
6. Tighten end cap bolts to specified torque.
8 7
a
b

d 4
1

3 2
e
51846
12
c
12 Loctite Master Gasket
5 6
a - Loctite Master Gasket
b - Upper End Cap Bolts – Torque to 150 lb. in. (17 Nm)
c - Lower End Cap Bolts – Torque to 80 lb. in. (9 Nm)
d - Add Light Oil to Threads and Bolt Face – 8 Bolts (3/8 in.-18)
Torque to 38 lb. ft. (51.5 Nm)
e - Bolts (5/16 in.-18) Torque to 180 lb. in. (20 Nm)

90-855347R02 NOVEMBER 2002 Page 4A-47

POWERHEAD

Assembly of Reed Blocks to Intake Manifold

aa

a - Torque to 105 lb. in. (12 Nm)

Assembly of Exhaust Divider Plate to Block

1. Place exhaust divider seal into slot in block.
2. Install exhaust divider plate with gasket.
3. Clean bolt threads with Loctite 7649 Primer N.
4. Apply Loctite 271 to bolt threads and torque bolts to 16.5 Ib. ft. (22 Nm).
5. Torque exhaust divider plate bolts in following sequence. Torque bolts to 16.5 lb. ft.
(22 Nm). Add Loctite 271 to threads.
19 18
10 15
13 14
9
6 5
3
1
2
d 4
b 7
8
c
a 11
12
50805
56167
16 17
a - Divider Seal
b - Exhaust Divider Plate
c - Gasket
d - Attaching Bolt

Page 4A-48 90-855347R02 NOVEMBER 2002

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6. If removed, install water pressure relief valve components as shown. Torque bolts to
specifications.

10
11
12
9
4
5
8
3
1

2 13
3
6 50803
7

1 - Cover
2 - Bolt - 150 lb. in. (17 Nm)
3 - Gasket
4 - Relief Valve Plate
5 - Diaphragm
6 - Water Deflector
7 - Washer
8 - Screw - 25 lb. in. (3 Nm)
9 - Spring
10 - Poppet Valve
11 - Grommet
12 - Carrier
13 - Washer

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POWERHEAD

CYLINDER HEAD INSTALLATION

1. Install each cylinder head to engine block with thermostat pocket UP. Apply light oil
to cylinder head bolt threads and torque bolts to 30 Ib. ft. (41 Nm) then turn an addition-
al 90°.
2. Install thermostat assembly into each cylinder head.
3. Install overheat temperature sensor into STARBOARD cylinder head below #1 spark
plug.
b d
a b c
b
10 9 c
f b e

6 5
2 1 g
h
i
3 4 j
7 8

11 12 56168

k
l
a - Elbow (Starboard)
b - Sta-strap
c - Hose
d - Elbow (Port)
e - Bolt [Torque to 30 lb. ft. (41 Nm) and then turn 90°]
f - Bolt [Torque to 17 lb. ft. (23.0 Nm)]
g - Cover
h - Gasket
i - Thermostat (143°)
j - Temperature Sensor (Starboard)
k - Bolt [Torque to 17 lb. ft. (23.0 Nm)]
l - Retainer

NOTE: The temperature sender provides continuous temperature information to the ECU
while the engine is running. Should temperature reach approximately 221° F (104.5° C),
the ECU will activate a warning horn and warning light.

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4. Thermostat and temperature sensor installed.

56163 56164

a - Thermostat (143° F 61.7° C)

b - Overheat Temperature Sensor

NOTE: When installing thermostat hoses, secure starboard to port thermostat hose with
sta-straps to prevent hose from being cut by alternator/air compressor belt.

a
b

a - Port Thermostat Hose

b - Sta-Straps

Reinstalling Engine Components

Reinstall the following engine components:

Section 2 Section 3
Starter Motor Direct Fuel Injection
Electronic Control Module Fuel Pump
Ignition Coil On-Board Oil Tank
Starter Solenoid Oil Pump
Alternator
Section 7
Flywheel
Shift Cable Latch Assembly
Control Cable Anchor Bracket

90-855347R02 NOVEMBER 2002 Page 4A-51

POWERHEAD

Throttle Lever and Shift Shaft

22
95 21
13 20

14
19
15 18

12

16 5
4

17 95

15
3
2 1

30 6
29 8
7
28
27 9

31 10
11
23

26 95
24
A 25

41

40 32
37 42
36 33
35
44
38
43
39
34

95 2-4-C with Teflon

A – Tighten and back off 1/2 turn

Page 4A-52 90-855347R02 NOVEMBER 2002

 POWERHEAD

Throttle Lever and Shift Shaft

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb-in lb-ft Nm
1 1 THROTTLE CONTROL LEVER
2 1 SCREW (.375-16 x 1-3/4 IN.) 20 27
3 1 BUSHING
4 1 WASHER
5 1 WASHER
6 1 SCREW (2-1/8 IN.)
7 1 NUT (1/4-20)
8 1 CAP
9 1 INSERT
10 1 WASHER
11 1 NUT 50 5.5
12 1 CAM
13 1 BUSHING
14 1 SCREW (M6 x 40) 45 5
15 2 SWIVEL BUSHING
16 1 THREADED BALL Drive Tight
17 1 LINK
18 1 ROLLER
19 1 THROTTLE ROLLER
20 1 SCREW (M5 x 16) Drive Tight
21 1 WASHER
22 1 STAR WASHER
23 1 ANCHOR BRACKET
24 1 LATCH
25 2 SCREW-Drive
26 1 CAP
27 1 WEAR PLATE
28 1 LATCH
29 1 WASHER
30 1 NUT
31 3 SCREW (.312-18 x 7/8) 160 18
32 1 GUIDE BLOCK
33 1 SPRING
34 1 LINK ROD ASSEMBLY
35 1 SHIFT SHAFT ASSEMBLY
36 1 ROLL PIN
37 1 SHIFT SHAFT LEVER–UPPER
38 1 BUSHING
39 1 WAVE WASHER
40 1 WASHER
41 1 NUT
42 1 IDLE STABILIZING SHIFT KIT
43 2 SCREW (6-32) 15 1.7
44 2 WASHER

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POWERHEAD

Powerhead Installation on Driveshaft Housing

1. Install Lifting Eye into flywheel.

WARNING
BE SURE that Lifting Eye is threaded into flywheel as far as possible BEFORE lift-
ing powerhead.
2. Using a hoist, lift powerhead high enough to allow removal of powerhead from repair
stand. Remove powerhead from repair stand, being careful not to damage drive shaft
housing gasket surface of powerhead.
3. Place a new gasket around powerhead studs and into position on base of powerhead.
IMPORTANT: DO NOT apply lubricant to top of driveshaft as this will prevent drive-
shaft from fully engaging into crankshaft.
4. Apply a small amount of 2-4-C with Teflon onto driveshaft splines.
5. Use hoist to lower powerhead onto driveshaft housing. It may be necessary to turn
flywheel (aligning crankshaft splines with driveshaft splines) so that powerhead will
be fully installed.
6. Install 10 flat washers and10 locknuts which secure powerhead to exhaust extension
plate/driveshaft housing. Torque locknuts in 3 progressive steps until secured.
7. Disconnect hoist from Lifting Eye and remove Lifting Eye from flywheel.
8. Reinstall plastic cap into center of flywheel cover.

b
51846

56162

a - Lifting Eye (91-90455)

b - Powerhead Attaching Locknuts and Flat Washers – Torque Nuts to 23 lb. ft.
(27 Nm)

Page 4A-54 90-855347R02 NOVEMBER 2002

 POWERHEAD

9. Install fuel cooler inlet and outlet water hoses to fittings on exhaust adaptor plate and
poppet valve cover. Install air hose from port fuel rail to fitting on exhaust adaptor
plate. Secure all hoses with sta-straps.
10. Install thermostat cover hose to exhaust adaptor plate.

b
d
56159 56158
c
a - Fuel Cooler Outlet Water Hose
b - Fuel Cooler Inlet Water Hose
c - Air Hose
d - Thermostat Cover Hose

11. Install 4 bolts securing bottom cowl halves and install bottom cowling.

52352

a
55932 55970 a

a - Bolt

90-855347R02 NOVEMBER 2002 Page 4A-55

POWERHEAD

12. Reconnect input fuel line.

13. Reconnect BLUE and GREEN trim harness leads to trim solenoids.

c
a
b
a - Hose Clamp
b - Fuel Line
c - Trim Solenoids

14. Reconnect remote control harness to powerhead harness connector and wires as
shown.

BLU/WHT BLU/WHT
GRN/WHT GRN/WHT aa
TAN
BRN/WHT

a - Power Trim Connections

Page 4A-56 90-855347R02 NOVEMBER 2002

 POWERHEAD

15. Reconnect warning gauge harness.

1 6

2 3 45

a
b
c
d

a f
b
c
d
a - TAN/BLACK
b - TAN/WHITE
c - PINK/LT. BLUE to PINK/LT. BLUE
d - ORANGE
e - Sta-Straps
f - Connect PURPLE to 12 Volt Source or Adjacent Gauge

IMPORTANT: Sufficient slack must exist in engine wiring harness, battery cables,
fuel hose, and oil hoses routed between clamp and engine attachment point, to re-
lieve stress and prevent hoses from being kinked or pinched.
1. Place the clamp over the wiring, hoses, and control cables as shown.

ÇÇÇ
b c

ÇÇÇ ÇÇ
ÇÇÇ
ÇÇ ÇÇ
ÇÇÇÇÇÇ ÉÉ
ÇÇ
a ÇÇÇ
ÇÇÇÉÉÉ
ÉÉÉ ÉÉ d

ÇÇÇÉÉÉ g
e

f
a - Battery Cables
b - Remote Wiring Harness
c - Warning Gauge Wiring Harness
d - Control Cables
e - Oil Hose with Blue Stripe
f - Fuel Hose
g - Oil Hose

90-855347R02 NOVEMBER 2002 Page 4A-57

POWERHEAD

2. Fasten clamp together with two screws.

a

a - Screws

3. Slide outboard shift lever into neutral position.

4. Install shift cable and secure with spring, nylon wear plate, flat washer, latch and lock
nut. Install throttle cable and secure with latch.

a
a - Shift Cable
b - Throttle Cable

Refer to Section 2 - Timing/ Synchronizing/Adjusting for engine set-up procedures.

Break-ln Procedure
CAUTION
Severe damage to the engine can result by not complying with the Engine Break-
in Procedure.
FUEL REQUIREMENTS
DO NOT use pre-mixed gas and oil in this engine. Use straight gasoline during engine
break-in and after engine break-in. The ECM is programmed to signal the oil pump to pro-
vide additional oil (50:1 ratio) during the first 120 minutes of operation. The ECM will moni-
tor this period through its own internal clock. At the end of this period, the ECM will signal
the oil pump to go to a standard ratio of 300 – 400:1 @ idle and 60:1 @ W.O.T.
ENGINE BREAK-IN PROCEDURE (ALL MODELS)
For proper procedures on initiating Engine Break-In sequence, refer to Section 3C.
Vary the throttle setting during the first hour of operation. Avoid remaining at a constant
speed for more than two minutes and avoid sustained wide open throttle.

Page 4A-58 90-855347R02 NOVEMBER 2002