2002 250HP DI/Ficht

took the boat out about a month ago and ran it for about 15 minutes and got an over heat warning. shut motor off and waited and the alarm went way until I was pulling back into the dock, and then the alarm sounded again. had good water pressure according to gauge

Went ahead and changed out the thermostats and impellar. impellar definetly looked mishaped and had problably lost some of its "spring". seemed to fix problem as i ran boat for about 4 hours or so with no issues. then coming back in the alarm sounded as soon as I came off throttle. shut motor down again and waited. alarm went away and seemed fine for the next 5 days of using it every day.

last day of vacation and taking boat back to the dock to put on trailer and overheat alarm sounds again, but this time letting it sit didnt seem to help. alarm came on very quickly after waiting.

was leaning towards maybe a faulty sensor. Any thoughts or direction is appreciated