Troubleshooting List - TOHATSU MFS25 Service Manual

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Troubleshooting
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1.Troubleshooting List

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Fuel level is low in the tank.
Fuel system connection is incomplete.
Fuel system sucks air.
Fuel pipe is twisted.
Cap vent is closed.
Fuel filter, fuel pump or injector is clogged.
Low quality gasoline is used.
Primer bulb is clogged.
Fuel feed pump (FFP) malfunctions or is clogged.
Water temperature sensor or MAP (Manifold Pressure) sensor is
o*
defective or the sensor circuit is disconnected.
Low quality engine oil is used.
Engine oil quantity excessive (Exhaust smoke is generated.)
o* Engine oil is lacking (Oil pressure switch operates).
o* Oil filter is clogged (Oil pressure switch operates).
o* Oil pump is defective (Oil pressure switch operates).
Use of spark plugs not specified.
Spark plug is contaminated.
No sparks or weak spark.
Stop switch short-circuited.
Stop switch lock is not put.
o o Defective wiring, earth, wire disconnected or loosened.
o o Battery charging is defective, or rectifier malfunctions.
o o Battery is dead, connection is loose or corroded. Battery electrolyte level is low.
o o 20A fuse is blown.
o Shift lever neutral (N) position is not proper.
o o Start switch or main switch is defective.
o Starter motor or starter solenoid operation is defective.
o PTT switch or solenoid is defective.
o Air is mixed in PTT fluid.
Valve timing is not correct (Belt is stretched or installed incorrectly).
Valve clearance is defective.
Valve seat sealing is defective.
Piston, piston ring and/or cylinder is worn excessively.
Combustion chamber car deposition is too much.
Spark plug is loose.
o* (Cooling water is lacking.) Pump is defective or clogged.
o* Thermostat operation is defective.
o Anti-cavitation plate is damaged.
o Use of mismatched propeller.
o Propeller is damaged or deformed.
o Thrust rod position is not correct.
o Boat is unbalanced by load position.
o Transom installation height is too high or too low.
Throttle link adjustment is defective.
* Low speed ESG operates.
Probable Cause
25/30 2006