Leaking oil

[99yam40]

old 86 model , makes me think check valves unless they have been replaced along with a new oil pump

[walleye1]

If the oil tank is not being over filed, may be a check valve problem.

[walleye1]

Is the boat oil tank higher than the engine [like mounted in a pontoon boat]?

[Ptol672018]

Hi, new to this forum and I wonder if anyone knows if it's possible that the oil pump is bad, the engine is a Yamaha 175hk 1986 model that has not been much driven with standing still for very long periods. The engine drains the oil through the carburettors when it is not running, what can it be? Can the oil reservoir on the engine be dense so that it gets over pressure or is it buying a new pump?