1978 Mercruiser 120 Hp problem with water in oil ?

nearpar

Petty Officer 2nd Class
Joined
Sep 4, 2010
Messages
143
I started working on my 78 Islander which has a Mercruiser 120hp I/O I tried to start the engine in my back yard but it turned very slow. I hooked a garden hose directly to the thermostat by pass for cooling. After cranking a few more time I removed all of the spark plugs and I noticed that the number 2 cylinder had filled up with water. ( why cranking was slow )
DO I have something cracked ??? or was I not supposed to hook up cooling water at the by pass ? And yes the crank case is also filling up too as the oil level has risen and is milk white. Any thoughts ??? Was I not supposed to have full water hose pressure on the engine ?

Thank you in advance
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 1978 Mercruiser 120 Hp problem with water in oil ?

If you have a crankcase full of milky oil, (it only turns milky by running) then you have a cracked block and are now in need of a new block or engine.
 

nearpar

Petty Officer 2nd Class
Joined
Sep 4, 2010
Messages
143
Re: 1978 Mercruiser 120 Hp problem with water in oil ?

Actually the water is going into the cylinder with the engine not running. Cracked Exhaust manifold ?
 
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