No thermostat?

[nickzlb77]

Having a problem with one of motors overheating intermittently. Mercruiser 5.7 inboard, fresh water cooled. Recently replaced the raw water pump and hoses.

Thought maybe it was the thermostat and found someone must have removed it. Im not as familiar with marine cooling systems but I would imagine a thermostat would be necessary to provide adequate backpressure and more consistent flow. Could this be my issue?

 

[Brentathon]

Re: No thermostat?

My "guess" is that a T-stat does not provide much backpressure when fully open, and therefore I doubt it would cause high temps if left out.
Maybe someone removed it to try to combat the high temps?

 

[nickzlb77]

Re: No thermostat?

Most likely. I'm kind of falling back on what automtive stuff, when running electric water pumps it's necessary to use a restrictor in place of the t-stat to provide some backpressure. Even if the t-stat is open it will restrict flow somewhat. Everything else appears to be in working order.

 

[Bondo]

Re: No thermostat?

Ayuh,... I donno if it's yer problem, but it is Necessary to have 1 installed...