1994 Mercruiser 3.0lx oil leak

[dlogvine]

I noticed some oil showing up on the sides and the top of the valve cover of 3.0 Mercruiser. I am lost as to where this oil could possibly come from, since I did not run the engine in at least a week and after I cleaned it up the same amount of oil again showed up ( also very small amount). The only possible source of a leak, since oil is showing up above the valve cover edge and on the sides of it, could be the vent hole on the top of the valve cover. The hose to the carburetor is really old and is quite loose, so that is my only guess. Any ideas? Thx
will post photographs tomorrow

 

[Scott Danforth]

the vent to the carb may have some oil vapor in it. that would be my first guess. make sure the hose fits the elbow in the valve cover so the oil vapor can drain back.

 

[Scott06]

Had the same with my 3.0, vent hose never seemed to fit right and 'kept the valve cover from rusting' ... just some blow by you can replace the hose or put a zip tie on it to seal it tight but nothing a rag can't fix.

 

[dlogvine]

Got a length of hose, 5/8" was too wide 1/2" a little smaller but at the end fit. With a tie it worked fine. Now ill have to wait to see if the leak disappeared. Thx

 

[dlogvine]

Thank you guys, there is no oil now! Problem solved

 

[dlogvine]

Unfortunately this was not the end of the story, when I took this boat to the lake and ran it for about 20 mins, oil started slowly getting from under the valve cover. Today I received a new valve cover gasket and removed the valve cover. As I expected the old gasket was in very poor condition, split in many places and barely covering anything. It was a miracle that the oil was pouring out so slow. Changed the gasket, will try the boat next week.