TOHATSU MFS 25d Service Manual

9-2
Troubleshooting
O K
4st 25/30 2022
* Low speed ESG is activated
1. Troubleshooting List
Engine will not start Engine stalls immediately after starting Defective idling Defective acceleration Engine revolution speed is high (High speed ESG is activated) Engine revolution speed is low (* Low speed ESG is activated) Boat speed is insufficient, or revolution speed is insufficient Engine is overheated Battery is not charging Starter motor will not operate Power tilt will not operate Warning lamp is lit Warning lamp is flashing Warning buzzer is activated
Probable Cause
Fuel and Lubrication Systems
QQ
Fuel tank is empty
QQQQ Q Q
Connection of the fuel system is incomplete
QQQQ Q Q
Fuel system is taking in air or is clogged
QQQQ Q Q
Fuel pipe is twisted or damaged
QQQQ Q Q
Air vent screw of the fuel tank is not open
QQQQ Q Q
Fuel filter, fuel pump, vapor separator, or injector is clogged
QQQQ Q Q
Performance of the fuel pump or vapor separator has dropped
QQQ Q
Gasoline is of poor quality
Q
Fuel is not fed under pressure by the primer valve or primer valve is clogged
QQ Q Q
Engine oil is of poor quality
QQ
Excessive engine oil (is generating exhaust smoke)
Q
*
Q
*
Q
* Insufficient Engine oil (activated the oil pressure switch)
Q
*
Q
*
Q
* Defective Oil pump (activated the oil pressure switch)
Electrical System
QQQQ Q
*
QQQQQ
*
Q
* Electrical parts are defective, wiring is disconnected, contact is poor, grounding is poor
QQQQ Q Q
Specified spark plug is not being used
QQQQ Q Q
Spark plug is dirty or worn
QQQQ Q Q
Ignition is poor (ignition system is defective)
Q
Stop switch short-circuited
Q
Stop switch is not locked or not fully inserted
Q
Rectifier is defective
QQQQ
Battery life is up, charge is insufficient, electrolyte level is low,
battery terminal is loose or corroded
QQ Q
Fuse is blown
QQ
Shift lever is not in the neutral (N) position
QQ
Key switch or starter switch is defective
Q
Starter motor or starter solenoid is defective
Q
Power tilt switch or power tilt relay is defective
Q
Power tilt fluid has air contamination
Compression System
QQQ
Compression pressure is insufficient
QQQQ Q
Valve timing is incorrect (belt is stretched, belt is installed incorrectly)
QQQQ Q
Valve clearance is insufficient
QQQQ Q
Intake or exhaust valve seat sealing is defective
QQQQ Q
Piston, piston ring, or cylinder is excessively worn
QQ
Carbon has built up in the combustion chamber
QQQQ Q
Spark plug is loose
Other
QQQ Q
*
QQ Q
*
Q
* Cooling water is insufficient, pump is defective, or is clogged
QQQ Q
*
QQ Q
*
Q
* Thermostat operation is defective
QQ Q
*
QQ Q
*
Q
* Anti-ventilation plate is damaged
QQQQQ Q Q
Mismatched propeller is being used
QQQQQ Q Q
Propeller is damaged or deformed
QQ Q Q Q
Thrust rod position is incorrect
QQQ
Load position is unbalanced
QQQQQ Q Q
Transom is too high or too low
QQQ
Throttle opening is insufficient

TOHATSU MFS 25d Specifications

General

Brand	TOHATSU
Model	MFS 25d
Category	Outboard Motor
Language	English