What can foul up my lawn mower's spark plug?
Answers:
Poor gas quality, oil leaking into the cylinders, too much gas. If too much gas, adjust the idle screws on the carburetor. If it's oily, consider getting a new mower, because that one's ready to be overhauled.
Other answers:
Water in your gas....Carbin build up...and oil in the gas....
Water in your gas....Carbin build up...and oil in the gas....
not running the motor in awhile,flooding the motor also.
Gas itself...if it gets wet with anything, it will not spark, so that includes gas, water, and oil.... of course carbon buildup and low compression will foul em as well.
Just get a new plug.....gap it, and install it.
But, to actually answer your question:
1) Age
2) Over use
3) Neglect
4) Improper gap
5) Engine misadjustments; bad air filter, bad gas filter, poor gas quality.
6) Bad plug wire
7) Bad connection betwen the wire and the plug.
I think those are the main things to check.
As for the gap, you should be able to find it online, but most are about 0.030" - 0.032" I believe, but you need to check to be sure. It does help to have the correct gap set.
Hope this is helpful to you.
oil buy a new one spark plug and see what happens maybe your piston rings are worn 4 stroke 2 stroke fuel/oil ratio wrong
Depends on what you mean by foul. If you remove the plug, is it oil covered or gas covered, or neither (just doesn't work). If it's oil, then oils getting into your cylinder because of a blown ring probably. If it's gas, you're either tilting the mover forward at too sharp an angle so the fuel is pouring into the cylinder, or the fuel supply system is bad.