Marinette Boat Forum

closed cooled - on start up, heats up to about 200, then drops to normal. Works fine from then on. 3 years on rebuild - SBC, just started this year.

Check tstat?

this won't be helpful. But I recall having that same issue (Chrysler 318's, 240hp)and can't recall what the solution was. Tstat replacement as suggested, seems cheapest, easiest way to begin.

I have had the same problem. The T-stat is sticking. If you want to change it, get one that fits a 350 but don't look in the T-stat housing. My Crusaders have the T-stat on top of the heat exchanger in the hose.

And be sure the new 'stat goes in the right way: the 'puck' (with the wax filling that opens the valve when it gets hot) goes towards the incoming coolant.

Jeff

I had this yesterday. Both engines more or less new this year, new Tstat (140). Both with new manifold s and risers. All pressure s and temperature s have been excellent on both my 1989 360 ‘s.
I just had a short haul and scraped the marine life off the bottom and intakes. So I took it out yesterday to keep the critters off. Ran great but both engines were at 200 F. Not much change when I idled or sped up. Raw water flow seemed good .

It is hot out her in MD , yesterday was only about 86, but high today is 91.

Weird— both engines!
Bud

Before you do anything else, buy/ borrow/ steal an infrared temp gun and see what's actually happening.

Jeff

thanks all - will try those things