On the side of the motor is the crank case breather.
Typically rectangular, and holds on with two bolts (probably
need 5/16 nut setter to get the small bolts out). The
breather sometimes has a tube that goes to the carb.
What happens, is that when the piston goes down, it creates
a tiny bit of pressure in the crankcase. So, they put a
breather (one way valve) on. So air can go out, but not in.
The crankcase runs at a very slight negative pressure.
These sometimes get clogged, and then the pressure from the
piston forces oil out. When you take the crankcase breather
off, it will expose the valve springs and ends of the valve
rods. These can sometimes be cleaned by soaking in kerosene,
or similar solvent.
There is a crankcase gasket which can be leaking. I've never
paid to have one replaced. Is it enough oil to mess up the
customer's driveway, or some other problem?
Christopher A. Young
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