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Evinrude Overheating Issue

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billygoat

New member
Hey everyone, new here, hope you can help me out.
Now I grew up working on 2-stroke motorcycles, and my Dad was a mechanic at a motorcycle/ATV shop for years.
So not a novice to engines, and this has us stumped

I picked up a 1991 25hp Evinrude, and I have not gotten it to run for more than 10 minutes at a crack yet.
It overheats, and I can not figure it out.
overboard indicator and water outlet both flowed

1st try - check thermostat, stuck shut with a piece of gasket - test run overheat.

2nd try replaced water pump - old was install wrong, that is where the gasket came from - test run overheat
tried backflusing water thru the thermostat hole and it stopped flowing, hmmmm

3rd try pulled the engine apart (covers) big glob of silicone in the water jacket around the cylinders - bingo!
cleaned it out, - test run overheat! - but I noticed this time that a lot of water was bubbling out the lower unit holes.

Pulled the power head again, checked the water inlet tube going into the head, and it was silicone in place with o-rings and all messed up.
Got that all cleaned up, and replaced seals etc. - water flows even better now - and OVERHEATS!!!!

I have torn the covers off again, can not find any blockage.
Compression on both cylinders is 100psi, it starts on the 1 or 2 pulls, and runs great until it warms up, so I don't think it is engine mechanica, I think it has to be water flow. - and yes the new t-stat opens in 150deg water.
And my heat gun verifies the motor is getting hot 400deg+ on the head, so it is not a bad overheat switch.

Any help is appreciated.
 
Whoever had that engine prior to you and was equipped with an excessive amount of silicone has the intelligence of a rock! Silicone has no place whatsoever on that engine. I'm afraid that you have a never ending job of clearing that junk out of the engine unless you tear it down completely to knowingly have all water passageways cleared.

I can only imagine what else he has screwed up that you'll encounter in the future. My apologies to come across so pessimistic but morons and idiots (some are both) should be barred from having tools.
 
I hear you there, step 3 I tore off every cover I could, and it all looks clean, yesterday I was spraying break cleaner thru the water passages tracing the path, and can not find any blockages
 
Now does someone have a picture or description of how these are installed?
Google search turned up very little detail.
Don't have the engine in front of me, but I am thinking since it was not obvious they were missing, it probably is not obvious how they are to be installed.

Thanks
 
Try 1 I found out you can not get the water tube lined up without pulling the lower unit (just putting the power head in), at least I didn't as evident from lack of water flow when I started it.
However once I corrected that it ran for a test run longer than I have had it running to date - combined.
So I am cautiously hopeful.

Thanks!
 
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