Logo
FULL SITE MENU

120 hp Mercruiser...water in oil

bill_w

bill_w

Advanced Contributor
Hi. Recently drove a friends boat for a bit. Mid to late 70's 120 hp mercruiser engine, 4 cyl. After about an hour on the water, we pulled in, trailered, drove home. Checked the engine oil at home, and it was about 1 quart overfull. Drained the oil, there was about a quart of water in the oil!!

This now happens every time it goes out. So, where in the heck is the water getting into the crankcase?? Compression is good, even all cyls, so I don't think it's a head gasket.

Any ideas???
 
Head went or the manifold went or the riser went. Take off the t-stat housing off the head look into the neck and with a screwdriver poke the wall opposite the opening.

Post back !
 
bill_w said:
Hi. Recently drove a friends boat for a bit. Mid to late 70's 120 hp mercruiser engine, 4 cyl. After about an hour on the water, we pulled in, trailered, drove home. Checked the engine oil at home, and it was about 1 quart overfull. Drained the oil, there was about a quart of water in the oil!!

This now happens every time it goes out. So, where in the heck is the water getting into the crankcase?? Compression is good, even all cyls, so I don't think it's a head gasket.

Any ideas???
Click to expand...

Ayuh,.... Most likely a freeze cracked block...
 
I'd go along with that...a freeze crack. Boat sat for years before my buddy bought it, don't know it the PO drained it right. Too bad, cause it runs great, just likes to mix a little water with its oil.
 
Back
Top