thermostat opening temp.

[Michael Lang]

1991 70 hp force

Noticed when testing newly purchased thermostat that it did not open until 140 degrees and it was installed with the small weep ( very small hole) at three o'clock instead of 12 o'clock, my overheat buzzer keeps going off and wondering if the 140 degrees opening temp. is causing overheat the buzzer to activate before the thermostat opens.

 

[MickLovin]

Re: thermostat opening temp.

Mine actually had a 110degF thermo, but it was a 80 chrysler 75hp

 

[MickLovin]

Re: thermostat opening temp.

Also shows a 130degF in the parts catalog, but I wouldn't think 140 would set the buzzer off.

 

[jerryjerry05]

Re: thermostat opening temp.

If the buzzers going off and the thermo's working as it should.
Then it probably the impeller.
Possible the system's clogged.
The 10d difference really shouldn't make too much difference.
The temp sensor usually doesn't work until it reaches over 160d or more.

 

[gm280]

Re: thermostat opening temp.

I'd verify there are not optional or other thermostat temperatures for your engine. And if there isn't, then I would look at both the water flow (impellor) and everything else to verify all is correct and cleared. If that all checks out correct, maybe the temp sensor is going out...

 

[Jiggz]

Re: thermostat opening temp.

Do a simple test by removing the t-stat for now. Ran the engine if the buzzer DOES NOT GO off you can conclude the t-stat is faulty or it could be installed backwards (some models allow you to install it backwards). However, if the buzzer goes off, then it could be a blockage in the cylinder water ports or a faulty hi-temp sensor. The hi-temp sensor is designed to go off at 160F.

 

[MickLovin]

Re: thermostat opening temp.

I would agree with Jiggz on someone inserting the t'stat in reverse, I have personally witnessed this being done from a PO of my outboard, I was wondering why it heated up only at WOT but would stay ok at cruise, the first thing I did was to check my t'stat. I didn't even realise it was in reverse until I went to put it back in and realised I was putting it in the complete opposite to how it came out, I checked my manual again and found I had put it in correctly. I then realised why it was heating up at WOT, it had enough flow at cruise, but as soon as I put more load down the flow could not keep up. The same can be said for a t'stat not fully opening, which is what I originally thought.