My friend has a Briggs and Stratton 16.5 hp engine on a riding lawn mower. He asked me if I had ever seen one that leaked oil from under the flywheel. He said there are two holes under the flywheel that oil is seeping out of. I am totally at a loss of the holes he is referring to and therefore I had no idea what to tell him. Has anyone seen this and can anyone tell me what could cause it? He said the holes are made into it.

Thanks,

There would not be any holes open to the crankcase. That would mess with the vacum required to operate properly. He is probably leaking from the top crank seal and the flywheel will spin that oil all over. Have him check the oil level and smell it for gas. Notorious for fuel seeping into crankase raising oil levels.

Ditto...
But gas in the oil won't make that seal leak.
What model, type and codes are on the engine?

I would guess that over full oil and gas mix would raise the level and push it out the breather and any other orifice. Oil leaks are tricky they spread the oil and are hard to find.