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Water in cylinder

catfish11

New member
"Hi. I could really use some

"Hi. I could really use some help here. I have a 1982 Merc 25 hp 2 stroke. I'm getting water on the bottom plug, and on the last outing I saw some water driping from the bottom of the cylinder cover. My engine knowledge is somewhat limited, though I do own a manual and am not too afraid to dig in to her... My questions: 1) After pulling the cylinder cover, it doesn't look like replacing the cylinder cover gasket is going to fix the water in the cylinder problem, though it may fix the drip-is this accurate? 2) I pulled the exhaust cover and manifold, ripping the inner gasket in the process, but it looked bad to begin with - could this be the culprit? 3) the top cylinder wall is slightly scored - even though it compression tests 125, how bad is too bad?

Thanks a lot for any help you can give me.

-Russ"
 
"Russ, the cylinder cover &#40

"Russ, the cylinder cover (water jacket cover) normally wouldn't be the source of water in the cylinder - but a new gasket there should fix the "drip".

It is more likely the water was getting in through the exhaust manifold.

This motor is a "headless" split block, so only a couple of ways for water to get in unless the cylinder(s) are cracked.

Technically, a slightly scored cylinder should be at least honed to clean it up - however, personally, I may not tear it all down for a slight score mark.

If your compression reading is accurate (and the same (rougly) in both cylinders), I might be inclined to just leave it alone for now....."
 
"Thanks a lot, Graham. You&#3

"Thanks a lot, Graham. You've renewed my hope in this engine...

I suppose that I haven't tested compression since this spring and have ran it all summmer - it may be poor now. It ran well all summer until the last trip to the lake...it ran so roughly that I didn't even leave the dock. I hoped that it was just flooded and needed to burn off the excess so I ran it for a few minutes...now I really hope that I didn't tear something up in the process.

I'll admit I've never seen a "used" piston or cylinder before and am not sure what is tolerable and what isn't. There seem to be slight lines in the top cylinder wall going lenthways, but these can't be "felt" with the plastic end of a pen. The slight score I mentioned earlier just barely can be.
I guess the only thing that matters is if it passes the compression test. (Which by the way, for a pull start engine that can't be pulled from high throttle (in gear), how many times should you pull the rope? Just until you get a 'max' reading?)

The parts guy that I called earlier in the week seemed like he was talking me out of needing a head gasket...is there not a head gasket for this engine? Everybody I've talked to seems to claim that it is the most likely problem - but none of them are really familiar with this engine.

I'll order gaskets tomorrow and give it a go when they come in.

Thanks!!"
 
"Russ, london marine is right

"Russ, london marine is right - no head gasket. This is what they call a split block. The powerhead "cracks" at the crank shaft. The "head" is completely enclosed in the upper half of the powerhead, and surrounded by the waterjacket.

The only access into the upper part of the head is the intake/exhaust manifolds and the spark plug holes...."
 
There is no head gasket. This

There is no head gasket. This is a "jug" motor like a motorcycle. The water gets in if the exahust divider plate is bad or the block cracked. The pistons will draw up moisture if the exhaust system is fouled up.
 
"You guys are fantastic...

"You guys are fantastic...

Is there a good way to determine if the block is cracked without the engine running? (If engine is running, this is where the soapy water comes in, right?)"
 
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