The paper cartridge air filter on my Briggs and Stratton tractor mower, is continually getting clogged up with oil. The filter is mounted upper most on the engine. Has anyone any suggestions please, as to why oil would be blown out of the intake?
there is a crankcase breather to the carb
so either you have overfilled with oil
or piston blow-by is over pressurising the crankcase
It happens that Mark formulated :
Yes, it had been over filled with oil in the past, level is now correct, so that might have been the cause.
How do I access / clear the crankcase breather please?
Either the engine is very worn and or the crankcase is pressurised, if it has a breather into the air filter, as most do. The crankcase generally has an air inlet somewhere, and the connection to the air filter draws fumes into the engine so they are burnt.
If the pressure in the crankcase is excessive - worn piston rings or valve guides - a considerable amount of oil can be forced into the intake.
First thing to check is the crank breather system is clear.
If it's anything like a car, there will be a pipe from the crankcase to the air filter assembly.
It's worth having a look inside the pipe - there should be a flame arrester (like a spiral wire jobbie). They often become clogged with carbonised oil, and block the pipe leading to pressure backing up into the crankcase and going goodness knows where.
My mistrust over people who call themselves "mechanics" derives in part from the fact that over the years, no one seems to have any idea what that part did, and just threw them in the bin. Probably along with all the nuts and bolts they had left over after a service. You know - the ones that weren't really needed.
Or he's tipped it on the wrong side when cleaning the underside, or has been mowing the wrong way on a steel slope. This happened to me with a B&S engined mower.
Pocket Bolts.
Nobody knows where they were supposed to go so they put them in their pocket.
G.Harman
The trick is to throw a handful of assorted nuts and bolts into the container, before starting. Then on re-assembly, you'll know there will be some left over, and not worry.
That sounds similar to the advice given to the frequent flyer who was worried about the 1 in 5 million odds of there being a bomb on the flight. In this case, the fact that the odds of there being *two* bombs on a flight were 25 billion to one against it was suggested "Bring your own bomb!" :-)
Wander over to the B&S website and download the manual for your engine. At the very least you'll get an exploded parts diagram which normall gives enough clues as to where a part is and what has to come off to get at it.
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