crank case vent pressure???? (1991 Mercruiser 3.0lx)

[steve242002]

Hi everybody, I'm not sure if i have a problem or not. Last summer my riser and intake failed within a few weeks of each other. I drained all fluids and put it away for the winter. I have replaced all necessary components and tried running it. It seems like i have a great deal of air pressure exiting the vent. My first thought was blown head gasket so i did a compression test. All for cylinders were 150. Almost no varition. How much pressure is too much? At lower rpms it almost feels like a pulse, like a single cylinder is blowing by. Could it be mis-adjusted valves or a bad valve guide? Thanks everybody.

 

[achris]

I've seen this on another 3 litre engine. I first thought the same, engine out, strip and rebuild. But the owner ran it for about an hour like that (just kept the hose off so as not to overwhelm the carb) and it cleared up and ran (still runs) perfectly....

Chris.....

 

[steve242002]

Ya, it seems to run really well, just a lot of pressure. ..