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Water in cylinders Merc 260 57

biglakeexile

New member
"Ok, I just got a deal on a 78

"Ok, I just got a deal on a 78 Sea Ray because the motor is bad. Being a gearhead, and also boat mechanic long ago i took on the challenge. After getting the boat and finding the motor wouldn't spin I pulled the spark plugs and found water behind cyl. 2, which had been in there for presumably 7yrs. Previous owner said it ran fine in 2001. So i took off the intake and heads and found heavy rust in cylinder 2, the intake runner of the head and through the intake into the other head. Naturally before I do repairs I want to know where the water came from. I have three possibilities I think, exhaust man., cyl head and or gasket, or even the intake. I took both exhaust manifolds while loose and attached a garden hose, no water into exhaust chamber. Also, there is no rust in exhaust ports of manifold or heads, which makes me think that wasn't the waters path. Looking at the head gasket remnants I see no obvious signs water leak. I also couldn't find a leak in the intake by filling the water jacket and watching for water leaking into the intake runner. Also, Cylinder 3 shows previous water damage but apparently it ran after that and cleaned it up a little. The intake on this guy connects cyl 2 to 3 across the motor. What do you guys think? I wonder if i could upload pictures of it here."
 
"Water could have gotten in fr

"Water could have gotten in from a bad exhaust shutter.

"heavy rust in cylinder 2" What will you do; have the block bored?

There is quite alot of rust and scale inside the water jacket. There may be some weak areas because of rust.

Have you checked the transom, stringers and floor for rot? Start there first."
 
On the exhaust shutter or flap

On the exhaust shutter or flapper valves are located in the top of the y pipe on my 1998 4.3. My boat dieseled on me and the motor ran backwards and sucked up water in the pistons and would not turn over.Mine were burnt out cause they are made of rubber. They are their for the protection to keep water out when going in reverse also.I replaced mine last week and had to take off the exhaust manifolds to get to them not a easy job since the manifolds are cast. Hope this helps.Need any more info let me no.
 
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