I have a poulon pro push mower with a briggs and stratton engine I bought about 8 years ago. This weekend I noticed oil leaking from the air filter. I can not determine the cause. Can you help.

Thanks

Is it a lot of oil? If not, don't worry about it.

If it is then, you either have too much oil in it or you have bad piston rings.

Could be engine crankcase is full of gas .