Mercury 150 hp 2 stroke injection oil leaking from under motor shroud in rear.

[irv9990]

I have a 1999 150 hp oil injected v6 mercury. I noticed small oil slick around motor after tying up in slip. When I removed shroud I noticed oil reservoir was very full.Somehow I don't remember it being that full before but I checked hhe cap and it appeared tight. After moping up oil in bottom cowl I looked on line and saw a 3 psi check valve in system by vent tube. If this check valve is shot would it cause oil to leak out vent tube? If not what would ? Thanks.

 

[Chris1956]

Oil injected Merc V6 motors usually have a large oil reservoir located in the boat. The motor pressurizes the large reservoir, causing it to fill the motor mounted reservoir. Those check valves you see are part of that system. if the cap is loose on the engine-mounted reservoir, or one of the valves or hoses leak, oil can be leaked into the cowling.