Overheat question

[bones774]

I have a 350 mag with alpha one drive, when cruising at low RPM for extended periods the temp starts to rise, as soon as we get underway the temps are fine and stay constant. Is it wise to try changing out the tstat initially just because it's simplest and see what happens? If so, any specific tstat, marine or auto? temp?
Thanks

 

[stonyloam]

Re: Overheat question

More likely the impeller is not giving you enough water flow at low RPM. When was the last time it was replaced? Does the temp creep up at idle? Sounds like the t-stat is working OK.

 

[bones774]

Re: Overheat question

Don't know when it was replaced as it's a "new to me" boat and yes the temps do crawl up at idle.

 

[stonyloam]

Re: Overheat question

Best guess it's the impeller. Tons of info here on how to do it yourself. Good luck.

 

[PitchFork]

Re: Overheat question

I had the same problem at the beginning of the season. It turned out to be the check balls in the TStat housing. The springs that hold the balls in needed to be streched out some.

 

[bones774]

Re: Overheat question

I had the same problem at the beginning of the season. It turned out to be the check balls in the TStat housing. The springs that hold the balls in needed to be streched out some.

That may be the problem. I know the guy I purchased the boat from and he paid alot of money to keep it maintained and yet when he sold it to me he mentioned the overheating and he said his mechanic told him that it was hard water deposits within the cooling system and not much to be done. It didn't sound right at the time and now i'm wondering if his mechanic tried fixing it with a new impeller and that didn't work, then he never took extra step for further diagnosis. The above fix is something many mechanics could overlook. I should take a look, it could be an easy 5 minute fix.

 

[bones774]

Re: Overheat question

I had the same problem at the beginning of the season. It turned out to be the check balls in the TStat housing. The springs that hold the balls in needed to be streched out some.

Hi, could you elaborate on the repair? Parts needed and work performed?thanks

 

[PitchFork]

Re: Overheat question

See spring #4 I streched them out to twice its size

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