The intake valve is not closed deep enough into the valve seat due to being too long and crankcase pressure is allowing some oil from the engine to be sucked up the valve guide into the combustion area and the 4 cycle process allows some of the oil to be pushed into the intake cycle and thus gets into the carburetor intake area and then into the exhaust system as the engine completes the cycle.
Can also be caused by the mower turning over or when the engine oil level too high.
the most common is because it was tipped or tilted
.004 intake.....006 exhaust
mower carbs built since around the mid nineties are non adjustable, except for idle speed,
The fuel filter for a Honda self propelled push mower with a Briggs and Stratton engine is located between the fuel tank and the carburetor. The fuel filter is only about one inch long.
Depending on how this mower got out of tune is how you are going to know how to tune it back. It may be as simple as adjusting the mixture screw on your carburetor, or as difficult as filing the points (older engine) or replacing the diaphragms on the carburetor.
One can purchase parts for a used Briggs and Stratton lawn mower from the following sources: Mower Graveyard, eBay, Briggs and Stratton, Zangler Repair, Lowes, Discount Online Parts.
Where is the location of the idle screw on the Briggs and Stratton 6.0 engine mulcher mower?
it may not have one. If it does it will be located on the fuel line between the fuel tank and the carburetor.
0.030 is the gap for briggs and stratton 4.5 hp mower
Briggs and Stratton does contract anyone to build mowers. The mower manufacturers contract Briggs and Stratton to build their engines (or whatever engine is on the unit). That is why you can have a Briggs and Stratton on most any type of mower. Same is true for Kohler, Tecumseh, etc. Not to say that the engine manufacturers do not build their own type of outdoor power tool but as the question states "snapper mower". Also keep in mind that if you have a snapper mower with a Briggs and Stratton engine and you need warranty work on the engine you need to go to an Authorized Briggs repair facility where as if you have a mower warranty then you need to go to an authorized repair facility for the mower manufacturer.
Briggs and Stratton and Kohler engines are considered quality components. Neither is likely to be better. However, the Briggs and Stratton brand is more popular.
You can find the operator's manual for that engine at www.briggsandstratton.com. You will need to contact the manufacturer of the mower for the lawn mower owner's manual. Briggs and Stratton did not amke that mower, only the engine.