My cousin had the same issue...couldn't start his mower for some reason. Didn't notice the oil coming out of the air filter box...FIL's compressor was shutting off so i took a look at it for him. Drained 20x more oil out of it than was supposed to be in there. He didn't realize comp oil was clear and couldn't see it in the sight glass so just kept adding oil until it was literally full.
Drained out half a bottle...but the mower takes a few mL at most.