Question on water temperature '95 OMC 4.3L

[MannyTC]

Hi everyone,

I looking for some guidance on an issue I have with my '95 Four Winns 170 Freedom that I just purchased recently. On my first outing to the lake I noticed that the temperature gauge never moved past its starting position on the left. This worried me since I had no easy way of knowing if I was operating at a good temperature.

When I got home I shorted the sensor wire at the sender to ground and the gauge did as expected and went all the way to the right. This led me to believe that the sender was bad. I changed the sender out and also changed the gauge out since I noticed that it would stick at the left and right on occasion. Now, the gauge does go to the left when the ignition is on and will go to the right when grounded. On the muffs I still did not see any change in temperature on the gauge.

I took the boat out to the lake yesterday and it did appear that needle moved a little to register 120 (the needle starts off a hair below the first line) but never goes above that. I am now guessing that the thermostat is stuck opened or has been removed altogether. I will check that out tonight.

Am I on the right track so far? Does anyone know what the proper operating temperature should be for the '95 OMC Cobra 4.3L GL? If replacing, what temperature thermostat should I be putting in? Anything else I should check?

 

[Bondo]

Re: Question on water temperature '95 OMC 4.3L

Am I on the right track so far? Does anyone know what the proper operating temperature should be for the '95 OMC Cobra 4.3L GL?

Ayuh,....... I think you're headed the Right way,.........

I'd think a 160* would be about Right for running in Freshwater........
I don't know if OMC uses the 145* for Saltwater or not........

 

[MannyTC]

Re: Question on water temperature '95 OMC 4.3L

Ok, I have some more questions now. I took off the thermostat housing last night. I did not see a thermostat on the manifold as I expected when I pulled it up. Instead, when looking at the housing from underneath I see what looks like a thermostat mounted a bit toward the top of the housing. Whatever it is it appears to be permanently in there since the opening seems smaller than the unit and it doesn't look like it will come out. When I wiggled it a little the spring popped back into the closed position so that unit was definitely stuck open.

Since I don't yet have the replacement thermostat to compare against what I see I am a bit confused. Can someone here clarify what I am looking at. I am attaching some pics of what I found when I removed the housing.

 

[Bondo]

Re: Question on water temperature '95 OMC 4.3L

Ayuh,......

You've found the T-stat..........

I Don't do OMCs,.........
But......
I think you'll find that there's a Sleeve holding the T-stat in place,....
When you get It Out,.... The T-stat will follow it......

Atleast there's abunch of Merc.s put together that way......

 

[Gary H NC]

Re: Question on water temperature '95 OMC 4.3L

It has a rubber o-ring that holds the stat up in the housing.
You should get the new o-ring with the new thermostat and gasket.
They usually rust so much the o-ring is hard to see...
Check your local Napa store,get the Napa-sierra kit..

 

[akwalker]

Re: Question on water temperature '95 OMC 4.3L

18-3653 Thats the Sierra part number for the t-stat kit. Ditto the last response, the O ring sits in a groove in the housing, and thats what holds it in.

 

[MannyTC]

Re: Question on water temperature '95 OMC 4.3L

Thanks for the help guys. Once I identified the o-ring it was pretty easy to get it out.

I looked at the Sierra catalog and it shows 18-3677 as the T-stat kit with o-ring and gasket. How is that different than the 18-3653?

I called all my local Napa stores and all said they can order the T-stat kit but don't stock them locally. :-( Guess I will just order from iboats.

 

[akwalker]

Re: Question on water temperature '95 OMC 4.3L

Not sure, but I just installed the tsat kit I mentioned in my 4.3 last week. NAPA got it for me overnight, along with a cap and rotor and wires.

 

[ifixit63]

Re: Question on water temperature '95 OMC 4.3L

the inpeller is bad in the pick up pump had the same time happen to me put in new one temp is fine now two boat shops told me all kinds of bull****

 

[Don S]

Re: Question on water temperature '95 OMC 4.3L

Welcome to iboat ifxit, please don't reply to old posts. This one is from 2007, somehow I think he may have fixed it within the last 5 years.