Mercruiser 3.0 low compression one cylinder

[ringorob]

I have a 2001 3.0 mercruiser. I had the motor rebuilt last year. The boat ran good for the whole year. Winterized and stored the boat in a garage. Took the boat out last weekend and had an issue with blow by, oil out through the valve cover. Checked compression and had 60PSI on cylinder 3, cylinders 1,2 and 4 were at 125. No water or gas in the oil. Oil pressure and temperature were right on. Spark plugs weren't fouled. Spoke to the company that I had the motor built through and they said that they believe the problem with the cylinder (maybe head gasket) was caused by an air pocket probably caused by a bad intake manifold. Does that seem possible, I have never heard of that before?

Company is saying that my warranty does not apply.

 

[Bondo]

Re: Mercruiser 3.0 low compression one cylinder

Ayuh,.... Welcome Aboard,.... Ya, a Lean condition will cause Detonation, which will burn the valves,...

Do a Leak-down Test to See where it's leakin' off,...

What was the reason for the rebuild in the 1st place,..??

 

[ringorob]

Re: Mercruiser 3.0 low compression one cylinder

Thanks Bondo, I bought the boat from a relative with a bad motor. Pulled off the head and found a screw stuck in the 4th cylinder, the piston was shreaded. Went to a place (not to be mentioned) and had the core rebuilt, first time back no oil pressure found out they forgot to put in a freeze plug, had to pull it and send it back. 2nd time, bad headgasket, pulled it and sent it back now a prioblem with the 3rd cylinder and they will not cover it under warranty. Have considered hitting the motor with a sledge hammer a few times!!!! The good thing is now I can take a motor out and put it back in with my eyes closed.

 

[Grub54891]

Re: Mercruiser 3.0 low compression one cylinder

Gee willekers... Nothing but issues with the shop,I'd be real leary of having them do anythig anymore!