I was riding in rough water yesterday and my over heat alarm went off. We were at the end of a pretty long run. I turned it off and checked things out. motor did not feel hot, water pump was working. After 5 mins the alarm stopped and we continued. Made the same long run back and it did not go off again. could my alarm be bad or is this a sign of a bigger issue?

Please help!

More information need. What engine do you have. What horsepower. What boat, bass, tunnel, flatbottom,deep-v? When was the last impeller installed. Freshwater or saltwater? Does it go off at a certain RPM or ????

Bass boat, 150 yamaha, 2000... had my service dealer change the impeller 8 months ago.

Oh boy.....We have had numerous discussions on this site because of what you are experiencing. Here's what I would do.
1st....replace impeller and housing and glue the pieces together
2nd....flush the block backwards and forwards
3rd....We pour muratic acid duluted (1-1) in the bung holes on top of each bank of cylinders and let the acid eat all the calcium out
4th....Remove and either streatch the popit valve spring 3/8" or replace it with a new one. and clean the grommet in that valve.
5th.... Replace thermostats.
6th.....pay the preacher an extra $10.00 next sunday and ask for special consideration.........good luck
That is a real common problem that Yammys experience and it's not our first rodeo with that.

Thanks for the help... Sounds like I should just take it to the shop... Well i might just flush it out good and hope for the best!!

Flush it out and hope for the best dont...Powerheads to expensive..just my 2 cents

couild it be the low oil alarm going off in rough water? should have alarm for no oil and low oil