Temp guage going crazy

[mx559]

I took my 2001 SAN out for the first time Friday everything worked great. Let my buddy take it out sunday since I was out of town and he said it ran fine. Put it in the water yesterday afternoon and right after starting it the temp guage was pegged out over 240. After about 2 min it came back down to where it should of been and then pegged out again after a while and came back down a couple times but most of the afternoon it was pegged. It wasn't running hot and was not in limp mode so I know that sensor is working so I wasn't too concerned about it. My buddy said if it was doing it on sunday he didn't notice it. Is it in the dash guage and is there any sort of quick fix for it or do I need a new guage? Thanks in advance for your expert advise.

PS. Tried searching for this problem, but the search on this new forum doesn't seem to be my friend...

[DanielC]

Check the nut on the temp sensor on the engine.
There are several sensors that look like temp sensors, check all of them.