Yamaha 100 outboard problems

Yamaha released its F100 outboard in 2001. This medium-sized outboard motor requires regular maintenance to keep it running smoothly. For owners experiencing problems with the F100, Yamaha provides a troubleshooting guide in the outboard's manual.


If the battery is discharged or damaged, the Yamaha F100 may have problems starting. Clean any build-up or debris from the battery terminals, recharge the battery with a separately powered charger and replace the battery if it is damaged or cracked. The F100 takes a 12.8 volt battery installed in a safe, dry place on the watercraft.


Ensure that the fuel tank has adequate levels of gasoline. If not, refuel the F100 using unleaded gasoline only. Yamaha recommends gasoline with an octane rating of 86 or higher.

Spark Plugs

Defective or damaged spark plugs can cause the F100's engine to misfire or stall. Remove and inspect the spark plugs, located in each of the engine's two cylinders. Replace either plug if it is burnt or damaged, and adjust the spark plug gap to exactly 0.043 inches. The F100 takes LFR5A-11 plugs.

Excessive Vibration

If the F100 is vibrating excessively, there may be debris tangled in the motor's propeller. Turn the outboard off, remove the engine stop switch lanyard and remove any seaweed or other debris that has become caught. Tightening the motor mounting bolt and the steering pivot can also help alleviate this problem.

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