CARBURETOR/FUEL PUMP

FUEL SYSTEM
Section 3A - Carburetor/Fuel Pump
Table of Contents
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-2 Carburetor Adjustments . . . . . . . . . . . . . . . 3A-14
Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-2 Electric Choke/Enrichener Adjustment . . 3A-19
Notes: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carburetor (20/25/JET 20) . . . . . . . . . . . . . . . .
3A-3
3A-4
Fuel System Troubleshooting . . . . . . . . . . . . .
General Information . . . . . . . . . . . . . . . . . .
3A-20
3A-20 3
Carburetor (20/25/JET 20) . . . . . . . . . . . . . . . .
Carburetor (Seapro/Marathon 15/25
3A-6 Carburetor Removal . . . . . . . . . . . . . . . . . . . . .
Carburetor Installation . . . . . . . . . . . . . . . . . . .
3A-23
3A-24
A
& Super 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-8 Fuel Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-27
Carburetor Adjustments . . . . . . . . . . . . . . . . . . 3A-10 Removal and Disassembly . . . . . . . . . . . . 3A-27
Low Speed Mixture Screw . . . . . . . . . . . . . 3A-10 Cleaning and Inspection . . . . . . . . . . . . . . . 3A-27
Main Jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-10 Reassembly and Installation . . . . . . . . . . . 3A-27
High Altitude Jet Chart . . . . . . . . . . . . . . . . 3A-11 Primer System . . . . . . . . . . . . . . . . . . . . . . . . . . 3A-28
Carburetor Jrt Orifice Size Chart . . . . . . . . . . 3A-12 Symptoms of a Defective Primer System . . 3A-28
Carburetor Float Adjustment . . . . . . . . . . . 3A-13 Servicing Sight Bowl Fuel Filter . . . . . . . . . . . 3A-29

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CARBURETOR/FUEL PUMP

Specifications
CARBURETOR Idle RPM (In Forward Gear) 750 ± 50
SPECIFI- Wide Open Throttle (WOT) RPM
CATIONS 20 4500 - 5500
25 5000 - 6000
Idle Mixture Screw
Adjustment (Preset-Turns Out)
20 1 ± 1/4 Turn
20 Jet 1-1/2 ± 1/2 Turn
25/25 Seapro/25 Marathon 1-1/4 ± 1/4 Turn
Float Level 1.0 in. (25.4 mm)
Main Jet Size (10-32 Thread Size)
19941/2 through 1996
-20 (WMC-44) 0.044 in. (1.12 mm)
-25/20 Jet (WMC-45) 0.076 in. (1.93 mm)
-25 Seapro/Marathon (WMC-46) 0.076 in. (1.93 mm)
-25 Seapro/Marathon (WMC-46A) 0.080 in. (2.03 mm)
1997 and Newer
-20 Jet (WMC-45) 0.076 in. (1.93 mm)
-20 (WMC-52) 0.044 in. (1.12 mm)
-25 (WMC-53) 0.076 in. (1.93 mm)
-25 Seapro/Marathon (WMC-54) 0.080 in. (2.03 mm)
Electric Choke Gap 0.025 in. (0.635 mm)

Special Tools
1. Carburetor Scale

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Notes:

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CARBURETOR/FUEL PUMP

Carburetor (20/25/JET 20)

20

19

18

16
2 17
16 17
17
21
1
17 17
13 17
28 3
27
17
17 25
17 10
6
17 17 17
17 24
16 9
17
11 23 5 16
17
16 16
17 17
14 22 16 17
12 17

4
17

7
16

16 17
17
8 15

26

= CONTENTS OF PRIMER/INJECTOR KIT, PART NO. 1395-9844A1, REFERENCE NO. 26

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Carburetor (20/25/JET 20)

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb. in. lb. ft. N·m
1 CARBURETOR (WMC-52 - 20HP)
1 1 CARBURETOR (WMC-53 - 25HP)
1 CARBURETOR (WMC-44 - 20HP)
1 CARBURETOR (WMC-45 - 25HP)(JET 20)
1 THROTTLE VALVE (20HP)
2
1 THROTTLE VALVE (25HP/JET 20)
1 THROTTLE SHAFT (20-WMC-44)
3 1 THROTTLE SHAFT (25-WMC-45)(JET 20)
THROTTLE SHAFT(20/25HP)(WMC52/52A/53/53A)
4 1 FUEL BOWL
5 1 FLOAT
6 1 VALVE–inlet needle
1 JET–main fuel (.044 - 20HP)
7
1 JET–main fuel (.076- 25HP/JET 20)
8 1 PLUG–jet retainer 32 3.6
9 1 COVER–diaphragm
10 4 SCREW–diaphragm cover 14 1.6
11 1 BODY–fuel pump
12 5 SCREW–fuel pump cover 18 2.0
13 1 COVER–fuel pump
14 1 COVER–fuel pump (JET 20)
15 1 PLUG 32 3.6
16 1 GASKET/DIAPHRAGM KIT
17 1 REPAIR PARTS KIT
18 1 PLATE–cover (MANUAL)
19 1 ELECTRIC CHOKE (ELECTRIC)
20 2 SCREW–cover plate 18 2.0
21 1 GASKET–carburetor
22 1 DIAPHRAGM/GASKET
23 1 GASKET
24 1 FLOAT PIN
25 1 FLOAT LEVER
26 1 PRIMER/INJECTOR SERVICE KIT (See illustration for contents)
27 1 SCREW
28 1 NUT

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Carburetor (20/25/JET 20)

* = CONTENTS OF PRIMER/INJECTOR KIT, P/N 1395–9844A1, REFERENCE #25

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Carburetor (20/25/JET 20)

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb. in. lb. ft. N·m
1 1 CARBURETOR (WMC-64 - 20HP)
1 CARBURETOR (WMC-65 - 25HP)(JET 20)
1 THROTTLE VALVE (20HP)
2
1 THROTTLE VALVE (25HP/JET 20)
3 1 THROTTLE SHAFT
4 1 SCREW
5 1 SPRING
6 1 VALVE–inlet needle
1 JET–main fuel (.044 - 20HP)
7
1 JET–main fuel (.076- 25HP/JET 20)
8 1 PLUG–jet retainer 32 3.6
9 1 COVER–diaphragm
10 4 SCREW–diaphragm cover 14 1.6
11 1 BODY–fuel pump
12 5 SCREW–fuel pump cover 18 2.0
13 1 COVER–fuel pump
14 1 PLUG 32 3.6
15 1 GASKET/DIAPHRAGM KIT
16 1 REPAIR PARTS KIT
17 1 PLATE–cover (MANUAL)
18 1 ELECTRIC CHOKE (ELECTRIC)
19 2 SCREW–cover plate 18 2.0
20 1 GASKET–carburetor
21 1 DIAPHRAGM/GASKET
22 1 GASKET
23 1 FLOAT PIN
24 1 FLOAT LEVER
25 1 PRIMER/INJECTOR SERVICE KIT (See illustration for contents)
26 1 FUEL BOWL
27 1 FLOAT
28 1 GASKET
29 1 SCREW
30 1 SCREW
31 1 NUT

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Carburetor (Seapro/Marathon 15/25 & Super 15)

20
18
10
16
9
17
2
16
17
17 26
21
1 17
17
17

17 3

15

6 17
17
17 25
17
17 17
16 24
17
23 5
11

16
17 16
22 17 19
14
12 17
4

13
28
7
27 16
17
8

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Carburetor (Seapro/Marathon 15/25 & Super 15)

TORQUE
REF.
REF
NO. QTY. DESCRIPTION lb. in. lb. ft. N·m
1 CARBURETOR (WMC-54)
1 1 CARBURETOR (WMC-46A)
1 CARBURETOR (WMC-56)
1 THROTTLE VALVE (WMC-46/46A/54/54A)
2
1 THROTTLE VALVE (WMC-56/56A)
3 1 THROTTLE SHAFT
4 1 FUEL BOWL
5 1 FLOAT
6 1 VALVE–inlet needle
1 JET–main fuel (.076) (WMC-46)
7 1 JET–main fuel (.080) (WMC-46A/54/54A)
1 JET–main fuel (.046) (WMC-56/56A)
8 1 PLUG–jet retainer 32 3.6
9 1 CHOKE SHAFT
10 1 CHOKE LEVER
11 1 BODY–fuel pump
12 5 SCREW–fuel pump cover 18 2.0
13 1 COVER–pump (WMC-54/54A/56/56A)
14 1 COVER–fuel pump (WMC-46/46A)
15 1 CHOKE VALVE
16 1 GASKET/DIAPHRAGM KIT
17 1 REPAIR PARTS KIT
18 1 PLATE–cover
19 1 SCREW–bowl drain 14 1.6
20 2 SCREW–cover plate 18 2.0
21 1 GASKET–carburetor
22 1 DIAPHRAGM/GASKET
23 1 GASKET
24 1 FLOAT PIN
25 1 FLOAT LEVER
26 1 CHOKE LINK
27 1 SCREW
28 1 NUT

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Carburetor Adjustments

Carburetor Number Stamped at Top of Carburetor Mounting Flange

Carburetor Number Model Main Jet Bowl Back Float Pre-Set Idle
H.P. Size Vent Jet Drag Jet Setting Mixture Screw
(Open)
WMC - 43 25 .080 None None 1.0 in. 1-1/2 Turns
Commercial (25.4 mm)
WMC - 44 20 .044 None None 1.0 in. 1-1/2 Turns
(25.4 mm)
WMC - 52 20 .044 None None 1.0 in. 1-1/2 Turns
(25.4 mm)
WMC - 53 25 .076 None None 1.0 in. 1-1/2 Turns
WMC - 53A (25.4 mm)
WMC - 54 25 .080 None None 1.0 in. 1-1/2 Turns
Commercial (25.4 mm)

Low Speed Mixture Screw

a

Rich
Lean

a - Low Speed Mixture Screw

Main Jet

a - Main Jet

High Altitude High Speed Jetting

Altitude Main Jet
20 25 SeaPro/Marathon
0 - 5000 ft. .044 in.* .076 in.* .080 in.*
(0 - 1524m)
5000 - 7500 ft. .042 in. .074 in. .078 in.
(1524 - 2286m)
7500 - 10000 .040 in. .072 in. .076 in.
(2286 - 3048m)

*Standard Main Jet

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High Altitude Jet Chart

Factory installed main fuel jets are normally adequate for proper performance up to
approximately 5000 feet (1524m) above sea level. Between 2000 feet (609.6m) and 5000
feet (1524m) the reduction of the main fuel jet may result in improved performance and
fuel economy. Above 5000 feet, however, it is recommended that main jet size be reduced
as shown per 1000 feet (304.8m) in the following chart. RETURN TO LOWER ELEVA-
TION: Carburetor jet changes must be reversed to avoid a lean fuel condition when used
at low elevation.

Feet 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 1100033 12000
Meter 304.8 609.6 914.4 1219.2 1524 1828.8 2133.6 2438.4 2743.2 3048 52.8 3657.6
Jet Size
0.034 0.034 0.034 0.032 0.032 0.032 0.032 0.032 0.032 0.030 0.030 0.030 0.030
0.036 0.036 0.036 0.034 0.034 0.034 0.034 0.034 0.032 0.032 0.032 0.032 0.032
0.038 0.038 0.038 0.036 0.036 0.036 0.036 0.036 0.034 0.034 0.034 0.034 0.034
0.040 0.040 0.040 0.038 0.038 0.038 0.038 0.038 0.036 0.036 0.036 0.036 0.034
0.042 0.042 0.042 0.040 0.040 0.040 0.040 0.038 0.038 0.038 0.038 0.038 0.036
0.044 0.044 0.044 0.042 0.042 0.042 0.042 0.040 0.040 0.040 0.040 0.038 0.038
0.046 0.046 0.046 0.044 0.044 0.044 0.044 0.042 0.042 0.042 0.042 0.040 0.040
0.048 0.048 0.048 0.046 0.046 0.046 0.046 0.044 0.044 0.044 0.042 0.042 0.042
0.050 0.050 0.050 0.048 0.048 0.048 0.046 0.046 0.046 0.046 0.044 0.044 0.044
0.052 0.052 0.050 0.050 0.050 0.050 0.048 0.048 0.048 0.048 0.046 0.046 0.046
0.054 0.054 0.052 0.052 0.052 0.052 0.050 0.050 0.050 0.048 0.048 0.048 0.048
0.056 0.056 0.054 0.054 0.054 0.054 0.052 0.052 0.052 0.050 0.050 0.050 0.048
0.058 0.058 0.056 0.056 0.056 0.056 0.054 0.054 0.054 0.052 0.052 0.052 0.050
0.060 0.060 0.058 0.058 0.058 0.056 0.056 0.056 0.054 0.054 0.054 0.052 0.052
0.062 0.062 0.060 0.060 0.060 0.058 0.058 0.058 0.056 0.056 0.056 0.054 0.054
0.064 0.064 0.062 0.062 0.062 0.060 0.060 0.060 0.058 0.058 0.058 0.056 0.056
0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.062 0.060 0.060 0.060 0.058 0.058
0.068 0.068 0.066 0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.060 0.060 0.060
0.070 0.070 0.068 0.068 0.068 0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.062
0.072 0.072 0.070 0.070 0.070 0.068 0.068 0.066 0.066 0.066 0.064 0.064 0.062
0.074 0.074 0.072 0.072 0.070 0.070 0.070 0.068 0.068 0.068 0.066 0.066 0.064
0.076 0.076 0.074 0.074 0.072 0.072 0.072 0.070 0.070 0.068 0.068 0.068 0.066
0.078 0.078 0.076 0.076 0.074 0.074 0.074 0.072 0.072 0.070 0.070 0.068 0.068
0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074 0.072 0.072 0.070 0.070
0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074 0.072 0.072
0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074
0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.074
0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076
0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078
0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080
0.094 0.094 0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082
0.096 0.096 0.094 0.094 0.092 0.092 0.090 0.090 0.088 0.086 0.086 0.084 0.084
0.098 0.098 0.096 0.096 0.094 0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086

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CARBURETOR/FUEL PUMP

Carburetor Jet Orifice Size Chart

Jet Orifice Size - Part
Inches Number
0.034 19266034
0.036 19266036
0.038 19266038
0.040 19266040
0.042 1399-5315
0.044 1395-7394
0.046 1399-5317
0.048 1395-6246
0.050 1395-6028
0.052 1395-6359
0.054 1399-5225
0.056 1399-5213
0.058 1395-7831
0.060 1395-6487
0.062 1399-4217
0.064 1399-4216
0.066 1399-4215
0.068 1395-6029
0.070 1395-6030
0.072 1395-6207
0.074 1399-3794
0.076 1399-3796
0.078 1395-6680
0.080 1395-6201
0.082 1399-3518
0.084 1399-3517
0.086 1395-5815
0.088 1395-6202
0.090 1395-6247
0.092 1395-5733
0.094 1395-8423
0.096 1399-6249
0.098 1395-7335

NOTE: –32 Thread Size

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 CARBURETOR/FUEL PUMP

Carburetor Float Adjustment

1 in. (25.4 mm)

17111
a - Carburetor Scale (91-36392)
b - Measured from Bottom of Float

e 52646

a - Float
b - Float Hinge
c - Float Pin
d - Bend Float Arm Here to Adjust Float Level
e - Needle

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CARBURETOR/FUEL PUMP

Carburetor Adjustments
1. Place outboard in water.
2. Check tiller handle cable adjustment for full throttle movement in both Forward and
Reverse gears. Adjust jam nuts for proper travel and to eliminate any slack.

57049
a - Jam Nuts

INITIAL CARBURETOR ADJUSTMENTS

Idle Speed Screw (Models So Equipped)
1. Shift outboard to Neutral and place throttle twist grip to Slow.
2. Push primer/fast idle knob completely in and rotate knob fully counterclockwise.

57037

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 CARBURETOR/FUEL PUMP

3. Back idle speed screw off of cam follower.

4. Turn idle speed screw inward (clockwise) until it just touches cam follower, then in-
ward an additional 1/2 turn to slightly open throttle plate.

57070

a - Idle Speed Screw

b - Cam Follower

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CARBURETOR/FUEL PUMP

LOW SPEED MIXTURE SCREW

1. Remove access plug from carburetor air intake cover (models so equipped).

57072

a - Access Plug
b - Intake Cover

2. Turn low speed mixture screw slowly inward (clockwise) until it seats lightly, then back
screw out (counterclockwise) 1-1/2 to 1-3/8 turns (turning mixture screw in tight will
damage needle and seat).
3. Do not install access plug at this time.

57071

a - Low Speed Mixture Screw

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 CARBURETOR/FUEL PUMP

IDLE WIRE ADJUSTMENT

1. Push primer/fast idle knob completely in and rotate fully counterclockwise.
2. Shift engine to Neutral.

57037

3. Adjust screw to remove all clearance between idle wire and trigger.

57070

a - Screw
b - Idle Wire

4. Check fast idle speed by turning primer knob to full clockwise position. Fast idle speed
should be 1500 - 2000 RPM.

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CARBURETOR/FUEL PUMP

IDLE ADJUSTMENT
Low speed Mixture Adjustment
1. Start engine and allow to warm up (run for several minutes). Throttle engine back to
idle for about one minute to allow RPM to stabilize.
2. Push primer/fast idle knob completely in and rotate knob fully counterclockwise.

57037

3. With engine running at idling speed while in Forward gear, turn low speed mixture
screw counterclockwise until engine starts to “load up” or fire unevenly from over-rich
mixture.
4. Slowly turn low speed mixture screw clockwise until cylinders fire evenly and engine
picks up speed.

57071
a - Low Speed Mixture Screw

5. Continue turning mixture screw clockwise until too lean a mixture is obtained and
engine slows down and misfires.
6. Set low speed mixture screw halfway between rich and lean.
7. DO NOT adjust leaner than necessary to attain reasonably smooth idling. When in
doubt, set mixture slightly richer rather than too lean.
8. Check for freedom from 4-cycling between idle and 2000 RPM (in Forward gear).
9. Install access plug into opening in carburetor air intake cover.

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IDLE SPEED ADJUSTMENT (MODELS EQUIPPED WITH IDLE SCREW)

1. With engine running at idle in Forward gear, make sure primer/fast idle knob is
pushed completely in and rotate fully counterclockwise to stop.
2. Adjust idle speed screw (a) to obtain recommended idle speed (see specifications).

57070

a - Idle Speed Screw

IDLE SPEED ADJUSTMENT (MODELS NOT EQUIPPED WITH AN IDLE SPEED SCREW)
For models not equipped with an idle speed screw, the carburetor has been calibrated at
the factory to maintain an idle speed of 650 ± 75 RPM in Forward gear.
Electric Choke/Enrichener Adjustment (Models Equipped)
1. With the engine off, check the gap between the electric choke plunger and carburetor.
2. Adjust the electric choke by loosening cover plate screws and moving cover plate to
obtain 0.025 in. (0.635 mm) gap. Torque screws to 18 lb-in. (2 Nm) and recheck gap.
3. Plunger must cover hole (in carburetor) when choked.

00228

a - Gap = 0.025 in. (0.635 mm)

b - Cover Plate Screw

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CARBURETOR/FUEL PUMP

Fuel System Troubleshooting

General Information
Problems that are thought to be caused by the fuel system may, in reality, be something
completely different. Items, that are shown in the list on the right, could give the impres-
sion that there is a problem in the fuel system.
1. Propeller
2. Spark Plugs
3. Ignition Timing
4. Ignition Spark Voltage
5. Cylinder Compression
6. Reed Valves
Typical symptoms and solutions in troubleshooting a fuel system are shown below:

Problem: Engine Turns Over but Will Not Start or Starts Hard When Cold.
Problem: Engine Idles Rough and Stalls.
Problem: Engine Runs Uneven or Surges.
Problem: Engine Will Not Accelerate.
Possible Cause Corrective Action
Improper starting procedure used. Review starting procedure as outlined in Operation
and Maintenance Manual.
Fuel tank empty or too low. Improperly mixed fuel. Check fuel in tank and replace or add whichever is
Contaminants (water, dirt, etc.) in fuel. necessary.
Fuel tank air vent closed or restricted. Check air vent on fuel tank. Air vent must be open
all-the-way and free from any contaminants.
Pinched, cut, restricted fuel line or loose fuel line Inspect all fuel lines and replace as needed. Tight-
connection. en fuel line connections.
Dirty or restricted fuel filter. Inspect and replace or clean all fuel filters.
Choke solenoid or enrichment valve not operating. Inspect solenoid or valve and wiring. Replace as
required.
Needle and seat in carburetor that is either stuck Refer to carburetor disassembly in this section.
open (flooding) or closed (no fuel).
Improper carburetor jet, restricted jet or idle mix- Refer to carburetor adjustments in this section.
ture screw out of adjustment.
Improper float level. Refer to carburetor adjustments in this section.
Low fuel pump pressure. Disassemble and inspect fuel pump components.
Defective anti-siphon valve. Inspect valve and/or test engine without valve in
fuel system.

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 CARBURETOR/FUEL PUMP

Possible Cause Corrective Action

Improperly mixed fuel. Contaminants (water, dirt, Check fuel in tank and replace if necessary.
etc.) in fuel.
Fuel tank air vent closed or restricted. Check air vent on tank. Vent must be open all-the-
way and free from any contaminants.
A pinched, cut or restricted fuel line. Also loose Inspect all fuel lines and replace as needed. In-
fuel line connection. spect and tighten all fuel line connections.
Dirty or restricted fuel filter. Inspect and replace or clean all fuel filters.
Low fuel pump pressure. Disassemble and inspect fuel pump components.
Defective anti-siphon valve. Inspect valve and/or test engine without valve in
fuel system.
Needle and seat in carburetor that is either stuck Refer to carburetor adjustments in this section.
open or closed.
Improper carburetor jet, restricted jet or idle mix- Refer to carburetor adjustments in this section.
ture screw out of adjustment.
Improper float level. Refer to carburetor adjustments in this section.
Carburetor loose on intake manifold. Check tightness of carburetor nuts.
Reed block loose or gasket defective. Using a pressure oil can, apply 2-cycle oil around
reed block housing/crankcase housing matching
surfaces and carburetor base. If engine RPM
changes, tighten bolts/nuts or replace gaskets as
required.
Improperly routed or restricted bleed hose(s). Refer to bleed hose routing in “Powerhead” sec-
tion.
Damaged fuel pump diaphragm. Disassemble and inspect fuel pump components.
Carburetor mixing chamber cover leaking air. Tighten screws or replace gasket.
Off idle holes plugged. Blow with compressed air.
Main nozzle or idle nozzle air bleed holes plugged. Blow with compressed air.
Damaged reeds. Refer to Section 4 for reed inspection.
Fuel pick-up outlet tube in fuel tank cracked. Replace
Wrong spark plug or improper spark plug gap Install correct plug or readjust gap.
Improper spark timing. Reset timing to correct specifications.

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CARBURETOR/FUEL PUMP

Problem: Engine Floods

Possible Cause Corrective Action
Dirt or debris are preventing inlet needle from Flush out inlet seat and clean inlet needle.
seating.
Worn inlet needle. Replace
Punctured float Replace.
Incorrect float setting Reset float.

Problem: Engine Runs Too Rich

Possible Cause Corrective Action
Fuel level too high. Reset float to correct level.
Carburetor floods. See preceding Engine Floods.
Idle nozzle air holes plugged. Blow out with compressed air.
Restricted air flow. Inspect cowl air inlet and carburetor for obstruc-
tions.
Main fuel jet loose. Retighten jet.

Problem: Fuel Blowback Out of Carburetor

Problem: Unable to Reduce Engine RPM to Slow Idle

Possible Cause Corrective Action

Chipped or broken reeds on reed block. Replace reeds.

Problem: Rough Idle

Possible Cause Corrective Action

Excessive preload on reeds. Replace reeds.

Problem: Engine Runs Too Lean

Possible Cause Corrective Action
Carburetor is loose. Air leaks past mixing chamber Tighten bolts securely. Tighten cover or replace
cover. gasket.
Fuel level is too low. Reset float level.
Clogged high speed jet. Inspect jet for varnish or debris and clean.
Restricted fuel flow to carburetor. Check fuel lines and filters for restricted flow.
Incorrect high speed jet. Refer to main jet chart and replace with proper jet.
Idle mixture set too lean. Adjust to run richer (turn idle mix screw counter-
clockwise).
Air leakage into fuel system. Inspect fuel line connections, hose clamps, fuel
pump and fuel outlet tube (located in fuel tank) for
loose fittings.
Anti-siphon valve restricting fuel flow. Inspect valve and/or test engine without valve in
fuel system.

Page 3A-22 90-826883R03 NOVEMBER 2002

 CARBURETOR/FUEL PUMP

Carburetor Removal
NOTE: Air intake cover has been removed for visual clarity.
1. Loosen primer cam retaining screw.
2. Remove retaining clip.

57069
a - Screw
b - Retaining Clip

3. Push down on primer arm and pull primer knob, bezel and slide block out of bottom
cowl.
4. Remove link wire from fast idle lever.
5. Disconnect fuel line from carburetor.
6. Remove carburetor mounting nuts.
7. Lift carburetor from engine.
e

d
c

b
57068
a - Primer Arm
b - Primer Knob
c - Bezel
d - Slide Block
e - Link Wire

90-826883R03 NOVEMBER 2002 Page 3A-23

CARBURETOR/FUEL PUMP

Carburetor Installation
1. Install carburetor with new gasket onto mounting studs. Start attaching nuts but do
not tighten.

a
b

57067
a - Gasket
b - Nuts

2. Install primer assembly onto carburetor. Position alignment hole on assembly over
post on bottom of carburetor.

57066

a - Alignment Hole
b - Post

Page 3A-24 90-826883R03 NOVEMBER 2002

 CARBURETOR/FUEL PUMP

3. Install air cover onto carburetor and secure with 2 screws.

4. Tighten carburetor attaching nuts.

57075

a - Screws
b - Nuts

5. Secure fuel line to carburetor with sta-strap.

6. Reconnect link wire to fast idle lever.

a
c

57070

a - Fuel Line
b - Sta-Strap
c - Link Wire

90-826883R03 NOVEMBER 2002 Page 3A-25

CARBURETOR/FUEL PUMP

7. Push down on primer arm and insert primer knob, bezel and slide block into primer
assembly.

c d

57068

a - Primer Arm
b - Primer Knob
c - Bezel
d - Slide Block

8. Tighten screw to secure slide block in place.

9. Align notch in back side of bezel with tab on bottom cowl and secure bezel in place
with retaining clip.

57069
a - Screw
b - Retaining Clip

Page 3A-26 90-826883R03 NOVEMBER 2002

 CARBURETOR/FUEL PUMP

Fuel Pump
Removal and Disassembly
IMPORTANT: Fuel pump check valve diaphragm and gasket should NOT be re-used
once the fuel pump is disassembled.
1. Remove 5 screws securing fuel pump assembly to carburetor.
2. Separate fuel pump components.
Cleaning and Inspection
1. Clean and dry all parts thoroughly.
2. Inspect pump body and base on carburetor for nicks, cracks or rough gasket surface.
3. Inspect pump check valve diaphragm. Diaphragm MUST BE flat and free from holes
and imperfections.
4. Pump body surface below check valves MUST BE flat so that check valve will seat.
Reassembly and Installation
1. Inspect all parts for serviceability.
2. Reassemble fuel pump.
3. Secure fuel pump assembly to carburetor with 5 screws. Torque screws to 18 lb. in.
(3.2 N·m).

e a
c
j
k

h
i f
g
a - Gasket
b - Pump Body
c - Spring
d - Cap
e - Gasket
f - Diaphragm
g - Pump Cover
h - Lock Washer (5)
i - Screw (5) [Torque screws to 18 lb. in. (3.2 N·m)]
j - Idle Timing Screw
k - Nut

90-826883R03 NOVEMBER 2002 Page 3A-27

CARBURETOR/FUEL PUMP

Primer System
The primer system provides extra fuel to the outboard whenever the primer knob is pulled
out. The primer system components should be inspected carefully for serviceability. The
diaphragm and gaskets should be inspected for cuts or abrasions. Replace accordingly.
The primer check ball and springs should be inspected for debris or varnish which restrict
free movement.
SYMPTOMS OF A DEFECTIVE PRIMER SYSTEM
1. Outboard is hard to start.
a. Diaphragm is cut.
b. Primer check ball is stuck in the closed position.
c. Primer passage is plugged with debris or varnish.
2. Outboard smokes excessively at idle.
a. Primer check ball is not seated due to debris, varnish or damaged check ball
spring.

a b

d
e
f

g
h
i
j
k
a - Seal
b - Screw (4) [Torque to 14 lb. in. (1.6 N·m)]
c - Cover
d - Diaphragm
e - Gasket
f - Spring
g - Primer Bowl
h - Check Ball
i - Spring
j - Gasket
k - Plug

Page 3A-28 90-826883R03 NOVEMBER 2002

 CARBURETOR/FUEL PUMP

Servicing Sight Bowl Fuel Filter

WARNING
Exercise extreme caution when cleaning fuel filter elements. Gasoline is extreme-
ly flammable and highly explosive under certain conditions. Always stop the en-
gine and DO NOT smoke or allow open flames in the area while cleaning fuel filter
elements.

CAUTION
DO NOT turn or twist fuel filter assembly when removing or installing. PULL
STRAIGHT DOWN when removing assembly. PUSH STRAIGHT UP when instal-
ling assembly. Turning or twisting fuel filter may break fuel line connection on fil-
ter.
The sight bowl fuel filter removes dirt and water from the fuel.
Check the sight bowl frequently and clean the filter as required.
1. Verify that the sight bowl rubber sealing ring is properly positioned in the bowl.
2. Reinstall element in filter cover.
3. Thread sight bowl onto filter cover.
4. Tighten bowl securely by hand.








 




1 - Fuel Line
2 - Sta-strap (4)
3 - Cover
4 - Filter
5 - Rubber Sealing Washer
6 - Sight Bowl
7 - Fuel Line Connector

90-826883R03 NOVEMBER 2002 Page 3A-29