Went out for the first sail of the season and my temp gauge pegged hot. .. didn't do anything since last year so was caught off guard.

I checked the"clip on" wire to the thermostat and that was still attached. The fan belt wasn't loose and there was plenty of anti-freeze. I have not yet changed the impeller but when I went under the boat it seemed to be pumping water as usual. This suggests to me that the water intake isn't clogged and the impeller is working.

The only thing left I can think of is the thermostat. Any other suggestions, and if it is the thermostat, how difficult is it to change?

Thanks
Chuck Parker