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Discussion Starter · #1 ·
My '93 85hp Yami dropped a couple cylinders yesterday. Rough idle (if at all), was able to coax it to cruise speed to get home and it sounded and ran great once there, but died when throttled back in the no wake zone....made it home somehow.

Looked at it today, getting water in the top 2 cylinders. No change in RPMs with both those plug wires off at "idle". No change with ether sprayed in them either. Water droplets on the plugs when pulled (they fire). 95psi in all cylinders. Have the head off now....

The cylinder "sleeves" look good, no damage to the mating surfaces to the head gasket, however there is a small chip out of each cylinder outer casting at the top (the casting that surrounds the sleeve). These are in the area of the fiber part of the head gasket, not the metal that contacts the cylinder wall sleeve. I'm not sure if water can get between the casting and the sleeve?

So my question....was this common on these engines? Is the block trash? A new powerhead is out of the question. Any area's of the block to check for visible cracks? Any comments? I am planning on slapping on a new head gasket tomorrow and hoping for the best if there is nothing else I can do. Maybe use some JB weld :D. Thanks!
 

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Are you sure you don't have water in the fuel? On a 2 stroke that's firing each time when a head gasket or mating surface goes bad firing compression will blow the cooling water out of the water jackets and she'll overheat. Water usually won't travel into the cylinder.
 

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Discussion Starter · #6 ·
Yeah Dunk I was hoping at first it was water in the fuel. I switched to a new 3gal tank with fresh gas before any other diag. The cylinders are wet enough not to fire even with spark at low rpm. When i coaxed it up to high rpm it slowly caught and sounded great, probably blowing water out of the jacket.

It was an easy head job on that motor so I didn't mind pulling it off and checking things out. I put her back together tonight, waiting overnight for some aviation sealer to set up before trying her out.

Thanks for the input guys!
 

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Discussion Starter · #7 ·
Top plug still getting wet with water. I'm thinking exhaust gaskets...tested a few of the bolts to see if they would come out and a couple may snap down behind the cowl where it will be impossible to drill out without removing the powerhead. I don't want to get involved with that on this old motor. Anything else anyone can think of before I sell this thing for parts?
 
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