2003 Yamaha F225 4 Stroke - Buzzer is stumping me

Just returned from vacation to the Gulf Shores area and the warning buzzer started going off around 3500 - 4000 rpm. It goes off and after I back down and take it back up it runs fine. It did this every time the engine stopped and was cooled for awhile. I had my regular mechanic run it and it happened to him but only once. He said we would need for it to happen more regularly before he could diagnose it. So went ahead and had another mechanic replace the impeller (kit) and both thermostats (they needed it) and the buzzer just took a little longer after running to go off again. What else could be wrong? It is a solid buzz and not intermittent. Any ideas? The 2nd mechanic mentioned possibly replacing the poppet valve but just seems like throwing $ at something they can't figure out.
Thanks for any help or ideas.

I had the same problem in my 2000-115 Yamaha. The problem was salt accumulatiom in the water jacket. You still get salt build up over the years even when you flush your engine after each use.

If you have access to an Infrared Temp gun you can easily locate the problem. The alarm will go off between 183-195 degrees. Normal operating is between 145-165 degrees.

The only other thing remaing to replace would be the sensor. The Temp gun would rule out a bad sensor.

Good luck !

Herb

I agree. It is probably salt build up, clean out all the water jackets, and you should be good to ge. The buzzer is an over heat alarm.

poppet valve is sticking