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What have I forgotten thermostat replacement on 43L

david_ray

Regular Contributor
"I last replaced thermostat ab

"I last replaced thermostat about 8 or so years back. As I wind up current sterndrive bellows replacement job, I decided to replace thermostat also while boat is in drive. I've worked on a lot of engines since then and do not remember the details, but I do not remember this much aggrevation. Please return me to Mechanic 101 for a refresher...

Pulled the thermostat housing, and thermostat does not want to come out easy. What I see--- the thermostat is deep recessed in the housing, and it appears a brass sleeve (liner) rests on top of the thermostat flange holding it securely in place. If this is true, then the sleeve must come out first, or both get pressed out together. Am I correct? ..cause I do not remember this action or spending much time on this task, but I do know I replaced the thermostat and making 5 trips to dealers to find someone who had one in stock.

Appreciate any refresher tips on this procedure, or a link to a writeup. I hesitate to use bigger hammer unless that is the proper procedure. Housing now sprayed with penetrating oil for the night."
 
"Remove the therm housing and

"Remove the therm housing and tap the thermostat out the top,the ring should come at the same time."
 
"Will do - what I thought, but

"Will do - what I thought, but did not remember that much detail of what I had done before. I figured it better to get an update here than do damage. Perhaps previously it fell apart easier when the system had a lot less age on it.

Thank you very much for the swift reply."
 
David:

I went thru the same


David:

I went thru the same thing you are doing. I have a DREMEL tool and used a coarse 50 grit sanding drum to cut out all the rust and scale build up--the reason it won't come out. I then used a finer grit drum to polish the inside for the new T'stat and brass spacer.
 
"Until it soaked overnight in

"Until it soaked overnight in penetrating oil, you could not even see the separation lines, giving poor visual analysis. As I awoke today, I did recall the previous time (I guess a senior moment!) and that at the time I had noted that this would be a poor repair to have to do out on the lake.
I ended up driving the old thermostat out (ruined now) and gently tapped the sleeve out from the bottom. Getting the old out exposed a slight ridge to align the punch. Cleaned up everything and lightly greased the sleeve to re-install. If time and weather permits, I just might get to launch late this weekend. Still have to put drive unit back on and check out the trim system, though I can work on the trim system at the dock if it needs anything else beyond the six new hoses.
Thanks for helping me get over my mental lapse."
 
Last fall I replaced the 20 yr

Last fall I replaced the 20 yr. old assy. w/a new one for $100 from eBay. The old one had too much rust and scale buildup internally. The ball check valves were sticking also. The new one has made a big difference in manifold cooling; temps are down and more uniform between banks.
 
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