[J J Hamm]

I have twin 1989 Yamaha 150 2 strokes. I just paid to have one of them worked on due to the overheating alarm going off. I got the boat back and still have the same problem with the same motor. The motor is running cool but the alarm goes off and it shuts down. Open for suggestions.

[rodbolt]

what method have you used to determine if its an over heat or oil alarm? what method was used to verify head temps on the motor that is supposedly cool yet its overtemp alarm is sounding?

[J J Hamm]

Thanks for responding. They took a portable temp gauge reader to take temps. The Yamaha gauge temp light goes on, then the buzzer goes off. I would of hoped these guys knew the difference between it being oil or a water issue. But this is why I am trying to trouble shoot it myself. Thanks for any help in advance !

[rodbolt]

how long will it run above 4500 before it overtemps? its possible the temp switch is bad. if the temp gun shows the head below 130 degrees and the alarm is sounding then while the horn is sounding look at the oil level in the engine tank. if its below the mark its oil. if its heat unplug the pink temp switch wire to isolate which side is hot. each head has a temp switch. if you find its an oil alarm that comes and goes inspect the filter in the remote tank.

[J J Hamm]

Thanks for the advice!