Water intrusion in mercruiser 170 head

RedRyder24

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Joined
Jul 20, 2021
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Hey all! Just purchased a 1986 Searay Seville a couple months ago. Engine appeared to be running good when I got it but when I took it out he first time I had problems with a couple things such as idle, timing, plugs. Did some work at home and had taken into a shop for the rest. Anyway, I took it out for a half day a couple weeks ago and was able to have 3 awesome hours out on the water. After about 2.5 hrs the engine staring making a claking sound. Shut it off and putted back to shore on the kicker. When I got it back home I removed the top on the head and found two problems. First the #1 cylinder intake push rod was badly bent. Problem #2 was that I saw pools of water and oil in the head. I decided to take off both manifolds and the head. I cleaned them all and didn't see any apparent cracks or unlevel surfaces on the block or head and the cylinders were clean with a little carbon buildup. I know the previous owner said he had the engine rebuilt recently. I was able to put in a new push rod, replaced all the gaskets and added some sealer around them for piece of mind. I pulled it out in the driveway and tried to start it and it fired right up! However, there are now still two problems I noticed during during and after test running it. The first being that water was appearing to be leaking out of the back of the engine, outdrive transom area into the bilge. This could be a loose hose or cracked seal. I have investigated too much. The bigger problem was after I took the head cover back off I noticed once again pools of water and oil in the head. So I'm not sure where to go from hear I though that replacing all of those gaskets should have fixed any water intrusion that was taking place but it appears it didn't. Does anyone else have any suggestions what I should do or someone who has had a similar problem. I'm trying to work around not pulling the whole engine apart. Thanks!
 
Joined
Mar 27, 2010
Messages
3,027
Are you seeing water or antifreeze under the valve cover?

What does the oil level look like? Has it risen at all on the dipstick? Here is a a thread of similar issue you can read up on. Just don't comment on it, it's 11 years old. https://forums.iboats.com/threads/mercruiser-470-raw-water-in-oil.739668/

See the attached photo from the factory service manual #8 which gives possible causes for water in the oil.
 

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