95 yamaha 70etlf overheat buzzer

tzmach1 · #1 July 13th, 2004, 03:52 AM

I recently purchased a 95 yam 70hp, it preforms great, but the overheat buzzer goes off if idling or running under 16000 rpm. If i run at higher rpm's it will preform flawlessly. Has good water flow even when the buzzer is going off. My question is how to tell if I need a water pump or temp sensor??? Or could I have a different problem?

WillyBWright · #2 July 14th, 2004, 03:07 AM

Welcome to iboats.

If water is peeing well at idle, then the water pump is fine. Scale can build up on the cooling side of the cylinders and insulate them from proper cooling, but that is usually a problem at upper RPMs. I'm betting on a sticky thermostat. Water will bypass the thermostat at higher RPMs. Most of the time it's scale on the thermostat and you can remove that with a good soaking in vinegar.