Yanmar 2YM15 Oil leak Pattern- Need advice please

[circa1971la]

I need some advice about my Yanmar 2YM15

6 months ago I had the engine serviced by a very reputable company out of Newport Beach, California.

A few weeks later there was an oil drip in a unique square shape drip that seemed to be coming from the starboard side of the motor. The mechanic came back and checked it and said it was “residual oil on the engine that was not cleaned efficiently during the last service”. He cleaned the engine and start/ran the engine at slip and did not notate any further leaks or drips.

A few months later after a lot of motoring to Catalina it recurred. They came back again and cleaned the area of the fluid and ran the engine and transmission to temperature but were not able to source any leak. They said it was “probable residual oil on the gear case, it is very difficult to get residual oil off the gear case due to the material it is casted in.

Now again it has recurred after a long day of motoring. The oil level is still ok and it runs good but obviously this is not normal. I’ve attached photos and would really appreciate any suggestions.

[skipperpete]

I’d take a close look at the oil filler cap on the timing cover, the oring might have fallen off during the service. The dipstick top end rubber collar also needs to be considered as a possibility and finally, the lift pump gasket. That should give you a good start toward finding what is a really miniscule oil leak, these are the hardest of all to locate.

[circa1971la]

Apparently it’s the injection pump gasket. Is this the same as the lift pump? I appreciate your help

[skipperpete]

Anything’s possible, the lift pump is attached to the side of the injector pump.