Hi, I have a 16hp briggs& srtatton twin cylinder engine with magnetron ignition, its an 1980 model.
Got the mower started after wiring problems sloved and now it is blowing oil out the vent tube that goes from the valve vent area to the carbrator breather housing. It runs good and does not miss at all. Any suggestions on why this is doing what it is. It takes it about 1 minute to start blowing oil out after started.
I was wondering if it could be the valve seal leaking, as it only does it on one cylinder.

Thanks, Charles

This is a side valve... wouldn't cause it if a valve seal was leaking... now a ohv with a blown head gasket sure...
Sounds like the breather is either gummed up or worn out... don't try to open it up or clean it, they are cheap to replace.

This is a side valve..... wouldn't cause it if a valve seal was leaking.... now a ohv with a blown head gasket sure....
Sounds like the breather is either gummed up or worn out..... don't try to open it up or clean it, they are cheap to replace.

I replaced the breather and still does the same thing.. kinda sounds like a knock now.. any more suggestions?

About the only other thing I can think of at the moment is either gas in the oil (making it too thin) or the oil ring on that cylinder...