Yamaha F2 5 Service Manual

69M3E118-4
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Ignition system8
Checking the ignition spark gap
1. Disconnect the spark plug cap 1
 from
the spark plug.
2. Connect the special service tool to the
spark plug cap and to the ground bolt.
3. Set the spark gap length on the adjusting
knob.
4. Crank the engine and observe the spark
through the discharge window of the
spark gap tester. Check the TCI unit or
spark plug cap if out of specification.
 WARNING
•Do not touch any of the connections of
the spark gap tester leads.
•Keep...

ELECElectrical systems
–+
8-569M3E11
Checking the TCI unit
1. Remove the spark plug cap from the
spark plug wire by turning the cap coun-
terclockwise.
2. Measure the TCI unit resistance.
Replace if out of specification.
Checking the engine shut-off switch
1. Check the engine shut-off switch for con-
tinuity. Replace if there is no continuity.
TCI unit resistance:
Primary coil:
White (W) – Black (B)
0.56–0.84 Ω
 
Secondary coil:
White (W) – Spark plug wire
11.6–17.4 kΩ
 
Lead color
White (W) Black (B)...

69M3E11
TRBL
SHTG
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9
Troubleshooting
Power unit ....................................................................................................... 9-1 

TRBL
SHTG
Troubleshooting
9-169M3E11
NOTE:
To diagnose a mechanical malfunction, use the troubleshooting charts pertaining to the trouble
located in this chapter. Also, when checking and maintaining the outboard motor, see Chapters 4–
8 for safe maintenance procedures.
Check that all electrical connections are tight and free from corrosion.
Power unit9
Symptom: Engine does not start (manual starter is operating normally).
Check the ignition system.
Check the fuel system.
Check the compression...

69M3E119-2
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NoClean, adjust or replace the 
spark plug.Good condition?
Check the compression pres-
sure of the combustion chamber.
Out of 
specification?
Yes
NoCheck the fuel system.
Out of 
specification?
No
Check the cylinder head, cylin-
der body, and piston assembly.
Check the valve clearance.
YesAdjust the valve clearance.
Power unit 

TRBL
SHTG
Troubleshooting
9-369M3E11
Symptom: Engine can be started, but does not remain on.
Check the fuel system.
Check the ignition system.
Check the compression pressure of the power unit.
Fuel system
Ignition system
Is the vent 
screw open?
Residue?
Kinks or fuel 
leakage?
Check for residue in the fuel 
filter.
Open the air vent screw.
Check the fuel hose for kinks or 
fuel leakage.
No
Yes
Yes
No
Check that the air vent screw of the fuel tank is open.
YesReplace the 
respective parts.
Check the...

69M3E119-4
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Compression pressure
Symptom: The engine idle speed is not steady, but increases or decreases.
Check the intake manifold.
Check the air intake system.
Check the ignition system.
Is there air 
intake?Replace the respective seals.
Check the compression pres-
sure of the combustion chamber.
No
Yes
Check that there is no secondary air intake on the contact surfaces of 
the carburetor.
Out of 
specification?
Check the ignition timing.
Yes
No
Check the operation of the 
throttle...

TRBL
SHTG
Troubleshooting
9-569M3E11
Symptom: Engine does not accelerate when the throttle is opened quickly.
The engine turns off when the throttle is opened quickly.
Acceleration is tardy and the engine is likely to stop at any moment.
Check the carburetors.
Check the ignition system.
Check the compression pressure of the power unit.
Check the throttle cable 
operation.
Do the car-
buretor throt-
tle valves 
close simul-
taneously?
Yes
Yes
No
Disassemble the carburetor and 
check the internal parts...

69M3E119-6
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9
Symptom: Shift mechanism of the forward gear does not operate properly.
Check the operation of the shift 
lever.
Replace the shift rod.
Check the bracket, spring, and 
ball.Good operat-
ing condition?
Connected 
properly?
Yes
Yes
No
No
Disassemble the lower case, 
and then check the operation of 
the dog clutch.
Yes
NoReplace the respective parts.Good operat-
ing condition?
Check the condition of the shift 
rod connection.
Check the forward gear.Power unit 

Index
i-169M3E11
A.
Adjusting the engine idle speed ................ 1-18
Adjusting the pilot screw ........................... 4-10
After test run ............................................. 1-18
Applicable model......................................... 1-5
Assembling the carburetor .......................... 4-9
Assembling the clamp brackets .................. 7-9
Assembling the crankcase ........................ 5-32
Assembling the cylinder block................... 5-31
Assembling the lower case...