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4-2
Outboard motor troubleshooting
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Symptom 1: Unstable engine idle speed, poor acceleration, poor performance, limited engine
speed, or engine stalls.
Symptom 1: High engine idle speed.
Symptom 1: Engine overheats.
Compression pressure
is low
Compression leakage
Measure the compression pressure.
Check the valve for bends or stuck.
Check the decompressor for proper
operation.
Check the piston and piston ring for
damage.
Check the cylinder for damage.
Improper valve timing
Check the valve timing.
Symptom 2
Cause
Checking step
See
page
Fuel not supplied
—
Check that the air vent screw is open.
—
Throttle valve does not
move properly
Carburetor malfunction
Check the throttle valve for proper move-
ment.
Throttle link and throttle cable
not installed properly
Adjust the throttle link and throttle cable.
Spark is weak
—
Check the CDI unit air gap.
Improper fuel and air
amount supplied
Choke valve does not operate
properly
Check the choke valve operation.
—
Carburetor malfunction
Adjust the pilot screw.
Disassemble and clean the carburetor.
Air leakage (carburetor to cylin-
der head)
Check the O-ring and gaskets of the car-
buretor and intake manifold.
Symptom 2
Cause
Checking step
See
page
Improper fuel and air
amount supplied
Carburetor malfunction
Adjust the pilot screw.
Disassemble and clean the carburetor.
Throttle link and throttle cable
not installed properly
Adjust the throttle link and throttle cable.
Symptom 2
Cause
Checking step
See
page
Cooling water not dis-
charged from the cooling
water pilot hole
Clogged cooling water inlet
Check the cooling water inlet.
Water pump impeller malfunc-
tion
Check the impeller.
Check the pin.
Water leakage from the water
pump housing
Check the insert cartridge.
Check the outer plate cartridge.
Check the water pump housing.
Leak or clogged cooling water
passage
Check the water pipe for damage and
proper installation.
Check the cooling water passage.
—
Thermostat malfunction
Check the thermostat.
Symptom 2
Cause
Checking step
See
page
Summary of Contents for F4B
Page 1: ...SERVICE MANUAL 6BV 28197 3M 11 F4B F5A F6C ...
Page 4: ......
Page 16: ...0 11 GEN INFO General information MEMO ...
Page 66: ...5 7 ELEC Electrical system MEMO ...
Page 160: ...8 19 LOWR Lower unit MEMO ...
Page 180: ...9 19 BRKT Bracket unit MEMO ...
Page 198: ...i 5 Index MEMO ...
Page 201: ......
Page 202: ...Jan 2019 ABE E_3 ...