I have a 4.0 B&S lawnmower engine. I am doing some repairs and when I tipped it on it's side oil leaked steadily from the breather. I noticed the panel was not exactly snug and tighted it. Still leaked when tipped. It's also a brand new gasket.
Now that there is oil on the gasket is it comprimised?
Thanks all.

Was all the old gaske removed good? scraped?


Possibility of the breather itself not seating well.

Yes, scraped with a straight edge razor. Is the new gasket still good since it now has been coated with oil?

i AM NOT SURE ABOUT THE MODEL YOU ARE WORKING ON, BUT THIS MAY BE NORMAL. ON SOME MAYBE ALL MODELS OF BRIGGSS 4 CYCLE, THE CHECK DISK ON THE BREATHER,WHEN THE DISC IS CLOSED, IS ABOUT SEVEN THOU OPEN. IF YOU LAY THE UNIT ON ITS SIDE, THE OIL WILL RUN OUT AND USUALLY INTO THE INTAKE. WHEN YOU START THE ENGINE, THE OIL WILL BURN OFF, THAT IS IF THE PLUG IS NOT OIL FOULED. IN THAT CASE, REMOVE AND SPRAY SOME CARB CLEANER ON THE ELECTRODE. YOU MAY HAVE TO SPRAYY SOME CLEANER IN THE PLUG HOLE AND PULL THE ENGINE OVER SEVERAL TIMES WITH THE PLUG OUT. WHEN ALL OF THE SMOKE IS CLEAR YOU ARE FREE TO GO. OH YES, SOMETIMES THE AIR FILTER WILL BECOME OIL SATURATED AND MUST BE CLEANED TO AVOID AN OVER RICH MIXTURE. I REALLY DON'T THINK YOU HAVE A PROBLEM.

Ps When It Is Necessry To Tip The Mower For Maintenance, Always Tip To The Side Opposite The Carb

Yes the new gasket is still good. If you tipped it the opposite side of the carb, or the other way, doesn't say much to why its leaking at the breather gasket. You didn't knick the mounting surface? forgot to ask, but the old gasket was removed from the breather if any stuck to it?

when you get the gasket problem resolved, it will still leak if mower is laid on carb side. This is normal

Just for the record, the carb is on one side and the breather is on the other.
So, no matter what side this goes on it is going to leak?
Thanks.

If it was leaned over and leaked out the gasket, it should NOT be leaking out of the gasket.