water in #4 cylinder on mercruiser 3.0

ive done a search and im still a bit confused as to what to look for. I have a mercruiser 3.0 I/O and am getting water in my #4 cylinder and its hydrolocking my motor. I am also getting water in the oil too somehow. I have pulled the manifold and checked inside the head ports and see no kind of cracks or rust scale. I have looked in the manifold and I did notice a hole in the rounded part of the manifold that seperates the water from the exhaust. cooling jacket I assume. ok with that said im confident that it is where my water is coming from but then how does it get into my oil pan ? motor ran great prior to finding this.

the riser/elbow should NOT have visable holes in it. water fouls the plug, cylinder dosent fire and the water gets past the rings

ok so I found a good manifold, same exact thing as the one I took off in excellent condition with a carb and riser for $50.00 and there is NO hole in it where there is one in mine so I think im good to go. gonna do a couple oil/filter changes on it and (fingers crossed) hopefully that's all it was and nothing more major. anything else I should check for or do ??? thanks

ok so now that I have a good manifold and have drained the oil and water out how do I get the rest of the water out of the block and other passages... I have heard diesel or trans fluid but am unsure of the best method..

hypersniper2010 said:

ok so now that I have a good manifold and have drained the oil and water out how do I get the rest of the water out of the block and other passages... I have heard diesel or trans fluid but am unsure of the best method..

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Ayuh,... Just fill it with fresh oil, 'n Run it,....
At temp, the remainin' water will steam off, Disappear,....