I have a newer model Toro push-mower with a Briggs and Stratton engine
that has generally been working great. A month or so ago, I somehow
overfilled the oil, and the next time I started it, the oil seeped out
of the air filter area and onto the top of the deck. It was a mess.

Now it has happened again, but I don't think it was overfilled this
time. The engine itself seems to be running fine. Does anyone know
what might be going on here? Have I unwittingly caused some damage?

Dave