Oil Coming out of Breather and Oil Cap

Siebs

Cadet
Joined
Mar 27, 2016
Messages
25
I have a 2004 Larson SEI with a Mercruiser 3.0 in it. I have had the engine rebuilt once already and shortly after the rebuild I noticed that the pressure coming out of the breather to the spark arrester, and the oil cap will pop off sometimes. Oil comes out and builds up in the bilge. I did a compression test on it and all of the cylinders are in the range of 130 to 140. The air coming out is not smoky and the oil is not milky at all. I am ruling out the head gasket as I have OK compression and I dont think it's rings for the same reason as it got new rings with the rebuild.

Any help would be great. I am fairly experienced and can do most diagnostic tests but am slightly stumped by this one.

Thanks
Brandon
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
Time for a leak down test. You pressurize the cylinder through the spark plug hole and then locate where the air is escaping by listening. Either it goes out the oil filler, meaning rings, the carb, meaning intake valves, or the exhaust, meaning exhaust valves.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
I have had the engine rebuilt once already and shortly after the rebuild I noticed that the pressure coming out of the breather to the spark arrester, and the oil cap will pop off sometimes.

Sorry to hear, but who ever did your rebuild didn't do it right
Blow by comes from rings not seating.

Hope it wasn't someone tried to dupe you and not bore the block and just put a set of rings on it
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,023
130 is a tired engine. You should be 150s at the very least on a fresh rebuild. See what happens with a wet compression test.
 

Siebs

Cadet
Joined
Mar 27, 2016
Messages
25
Motor is out already. Best place to purchase a reman? Michigan Motorz?
 

Siebs

Cadet
Joined
Mar 27, 2016
Messages
25
Leak down test pretty much showed its gotta be the rings.Motor is out already. Best place to purchase a reman? Michigan Motorz?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
MM has had no complaints here that they didn't take care in short order.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,023
Just placed an order with them. Knowledgeable, extremely friendly so far.
 
Top