Was checking everything before we take the boat out tomorrow and saw this while i was cleaning the flame arrestor
The hole throttle body and intake manifold has a coating of oil inside. Looks like its coming from the valve cover breather passage on the throttle body. Im thinking worn rings allowing to much blow by and forcing oil up the breather, but what else could cause this. Any opinions? Its a 98 Merc 7.4L MPI and Bravo 1.