1988 3 cyl t-stat info?

[electricjohn]

I am getting water out of the weep hole on the T-stat cover and want to change out everything under that cover. Does Merc sell a kit, or do I have to buy parts separately? Got cover bolts loose, should I expect any surprises? I have a FSM and parts list.

 

[Texasmark]

I had a 2002 90 triple and under the cover was the 142F stat (pellet stamped) and the popoff valve which bypassed the tstat starting at 2500 rpms. Metal, springs, and rubber seals. Not rocket science. I used blue RTV when I put my cover back on rather than using a gasket which I didn't have. Worked fine, water pressure is less than 15#.

 

[wn6ngp]

I did the same on my 2000 90hp triple. My motor had trouble staying warm enough so slow speed was a problem. After I took it apart I wished I had done it a long time ago considering I run in salt water periodically. I just went to the dealer and got a kit of parts, not much $. It was one of my easier jobs.

 

[electricjohn]

Thanks, I found the part # for the poppet kit, 803060T1, which does not include the cover gasket. Trying to figure out which stat kit I need. Hoping that has the gasket, if not, I buy separately. Took some time getting those cover screws loose last fall. Now hoping the cover pops off easy.

 

[Texasmark]

Thanks, I found the part # for the poppet kit, 803060T1, which does not include the cover gasket. Trying to figure out which stat kit I need. Hoping that has the gasket, if not, I buy separately. Took some time getting those cover screws loose last fall. Now hoping the cover pops off easy.

On the screws, I use blue thread locker as it not only keeps the screw from backing out it provides a non metallic medium between SS and alum and allows for easy removal when required. The Merc manual specifies RED thread locker when it specifies one and I don't understand that.

I worked in industry for 36 years and blue was the color because it is for assemblies that require servicing. Red is for build it and forget it.....trash it if it breaks as you can't get the screw out without heat and a lot of whoopie and the heat to get it out may damage other parts not part of the screw removal repair.

 

[wn6ngp]

Now I remember that the T stat was unique via s/n which was one of the reasons I went to the dealer. When I went there the T stat gasket did not come with it and he was nice enough to pull one out of a another set that had extra. Its odd how there are so many ongoing changes in the same model happening with something so common as a T stat but it is common.

 

[electricjohn]

On the screws, I use blue thread locker as it not only keeps the screw from backing out it provides a non metallic medium between SS and alum and allows for easy removal when required.


30 years and 1300 hrs before service was needed, hoping only once. Looking forward to seeing what salt did in there. Run in fresh water too and always flushed.

 

[Texasmark]

On the screws, I use blue thread locker as it not only keeps the screw from backing out it provides a non metallic medium between SS and alum and allows for easy removal when required.


30 years and 1300 hrs before service was needed, hoping only once. Looking forward to seeing what salt did in there. Run in fresh water too and always flushed.

Yes but "you are either already in or going in there" if this is referencing type of thread locker. Your main concern, if you haven't discovered it already will be getting the cover's mounting screws out without snapping off the heads.

I think it was "Racer 1" that posted on here that he grinds the heads off the bolts to get at the threads, soaks them good with penetrating oil for a bit and uses a set of ViseGrips to grasp the shank and remove it.

I have had good luck with the penetrating oil (not WD-40) for a 24 hour or so soak and then impact tool removal of the screws. For some reason screws will respond to the impact method whereby using just plain brute force will twist the head off if corrosion has seized the threads....normal problem with aluminum blocks.

When going back together, I like to take a tap and thread chase the holes in the block and if available, use new bolts.

 

[racerone]

Stainless bolts in a salt water environment may suffer from something called ----" hydrogen embrittlement "------If you have never heard of that you can look it up.

 

[electricjohn]

I got all 5 bolts loose last fall with a little patience and care. Cleaned them up and reinstalled them with anti-seize till now.

 

[Texasmark]

I got all 5 bolts loose last fall with a little patience and care. Cleaned them up and reinstalled them with anti-seize till now.

Then they ought to come right out; with resistance but will come out without breaking off. Don't forget the anti-seize this time.....thread locker is an anti-seize too.

 

[electricjohn]

I got some blue.

 

[Texasmark]

I got some blue.

Wink! Wise man.

 

[electricjohn]

Finished the job today. Everything went easy. Poppet valve diaphragm had a small hole. Getting the plastic poppet valve carrier out of the block was a challenge. No real evidence of salt corrosion.