302 mercruiser

[bbdropshot]

I have a 76 wellcraft that i swaped for and it has twin 302's both of them had the freeze plugs pushed out, so i put them back in and started the engine and put the water to it and water starts getting in the oil. I changed the intake gasket on one of them and water still gets in the oil, I'm hoping its a head gasket, what's everyone else think, compression test came back good on one motor, and the other moter all cylinders where good, but one had water in it when i tried the compression test, the engines idle good and everything, so i just don't know.

 

[cooter2506]

Re: 302 mercruiser

If compression test came back good you probably have a cracked head or exhaust manifold.

 

[bbdropshot]

Re: 302 mercruiser

I guess i'm going to tear into it and see if the head looks good, and if it is then i'll try a head gasket and see what happens. Are those exhaust manifold gaskets different than a regular 302 truck manifold gasket? I was looking at the regular gaskets at oreilly's and they looked a little different than the marine gaskets.

 

[danond]

Re: 302 mercruiser

Yikes. I hope you gave the other guy a non-running, expensive to fix boat in exchange!

Marine gaskets won't corrode.

 

[bbdropshot]

Re: 302 mercruiser

I thought i had the problem fixed after i put the intake gasket on, i started the motor and let it idle for a while kept checking oil it was good so i reved it higher and the water started mixing in the oil.

 

[bruceb58]

Re: 302 mercruiser

You need to pressure test the water passages of the block but odds are both have cracked blocks. A new head gasket won't solve anything.

 

[bbdropshot]

Re: 302 mercruiser

definately not the answer i was lookin for

 

[Surfdancer]

Re: 302 mercruiser

I bought a project boat 2 years ago with a single Mercruiser 888. Same symptoms as yours. It ended up being a crack in the head casting by the rocker arm studs.

It didn't affect compression, but water would get into the oil big time.

 

[Bondo]

Re: 302 mercruiser

You need to pressure test the water passages of the block but odds are both have cracked blocks. A new head gasket won't solve anything.

Ayuh,... Agreed...