2001 150 water in cylender

[jgreen1238]

Well, my dads boat is drowning him. He is retired and broke. So this engine problem has been a pain in his butt and mine. Since he has no where else to turn, I have adopted the problem. A year agoe his motor started having power issues, not bad but noticeable. So I changed the spark plugs on a first attempt and noticed water on a clean plug. Not sure the number but it is the center cylinder on the left facing the rear of the engine. Then I took off the head to replace the head gasket and saw ther was a fair amount of damage to the cylinder bore but the gasket looked good. We had a guy bore and sleeve the cylinder and try to find where the water was comming from. Well long story short, He spent 1500 bucks and we still have a leak.I replaced the head for a cheap stab in the dark but it didnt fix the problem.
What I know: it is definately not the head, head gasket or water in the fuel.
What i dont know:where to go from here.
I am realitivly familiar with car engines but outboards are not something that i know much about internally. If it were a car I would say its A cracked cylinder, but since it has been sleeved wouldent that be ruled out?
My next thought is maybe the exhaust valve is leaking and sucking it in through the manifold but i cant find the valve. I know... dont laugh.
Lastly, when we changed the plugs the motor would run good for about 10 minutes before fowling the plug. Indicating to me that it is a small leak.
Any help would be appreciated.

[jgreen1238]

also is there somewhere I can get a breakdown on this engine? thanks again.
Oh, and sorry, I know I cant spell.

[boats.net]

May be a hole corroded through exhaust inner plate, remove the inner plate and clean carbon off and look for a hole into water jacket side of plate.
Number 11 in this diagram, 2001 150TXRZ Yamaha Outboard CYLINDER CRANKCASE 2 Diagram and Parts

[jgreen1238]

awsome, Thanks for your help

[jgreen1238]

Took the plate off and found a hole. WOO HOO. You were right on, thanks for your help.