Water intruding into cylinder

[tavacska]

Motor is 1977 Mercury 1150.
The power head and exhaust baffle are taken out. There is water intruding. Just have to figure out where is the water coming from.

1. The power head is dissembled after running the motor for 15 minutes on muff.
2. On the power head seating plate, the bottom shaft cap is all covered by white cream.
3. On baffle plate, the area is covered by cream from 2nd cylinder to under. #1 is completely dry.
4. The soot on power head seat gasket seems to be ok around the exhaust down port and crankshaft. It looks to me the water is not intruding from bottom. Otherwise, the cream on the lower shaft cap should be washed away. The covered cream comes from inside the powerhead?
5. The soot on the exhaust side seems to be good on the perimeters. There is no clear sign that water intrudes from loose gaskets.
6. The soot on the inner plate is ok to me too. Only #6 clearly has no much soot. But this is also due to most water exhausted from this port.


Opinions? Really struggled to find the intruding area.

 

[racerone]

Remove the inner exhaust cover to inspect gasket there.----Look for issues with that cover.

 

[tavacska]

Remove the inner exhaust cover to inspect gasket there.----Look for issues with that cover.

I will check that. The inner cover was replaced with a brand new one 1 year ago. Should be fine.

 

[tavacska]

BTW, any opinions on WSM, Sierra gasket set?

 

[Faztbullet]

Either inner baffle plate warped/gasket blown out, lower seals bad. cracked block or chipped reed. If inner baffle plate has blown need to have block resurfaced to true flat and new plate with resiweld epoxy.

 

[tavacska]

Inner plate taken off today. Gaskets very good. Soot exist along all sides.
It must be some cracks on the block, which is hard to see.

 

[Faztbullet]

I suggest start looking for a different motor of near same year and swap powerheads with know running on and existing one for parts..

 

[QBhoy]

It would be great if it was water from the fuel tank. Never that easy though.

 

[tavacska]

I am working on the replacing the powerhead. It's a brand new block.

My pistons turn out to be 5 high dome(original) + 1 low dome(#2, replaced), and that's why the #2 compression is 125 psi vs 130 psi of others.

Questions are:
1. Will the block be the same for high/low dome pistons? I believe the block is older than 1977 model, because there is no water hole to inner plate from under the block.
2. Do I have to find a high dome piston to replace the #2 piston?

Thanks.

 

[Faztbullet]

Be careful on block as a older block could be a "D" port vs a square port and some older blocks are 8 bolt vs 10 bolt. These will not interchange