What does it mean when your lawn mower spark plug has oil on it?
You may find oil on a spark plug because: Too much oil was mixed with the gasoline. The piston rings (the component that seals piston and cylinder) are failing. If these rings are broken or failing in some way, they can let oil slip past the piston and get on the spark plug.
Keeping this in consideration, what causes a spark plug to be oiled fouled?
Oil fouling occurs when oil is allowed to enter the combustion chamber. Oil deposits cover the spark plug which can keep the spark from arcing across the gap. Instead it takes the shorter path to ground through the oil. Usually a sign of advanced engine wear.
Oil could be leaking into the cylinders, getting past pistons that are worn or valve guides that are worn. Finding the source of the leak is very important – consult a mechanic for guidance. Once the problem is addressed, you can replace the spark plug.
Then, should spark plugs have oil on them?
Oil is also important for lubricating the components of the engine while it is running. If you do not have a good supply of oil, then your engine will overheat from all the friction created by moving components rubbing against each other. However, you'll never want to have oil leaking into the spark plugs.
Can oil on spark plugs cause smoke?
If oil is leaking onto a spark plug tip in the combustion chamber of an engine, it will most likely burn with the air-fuel mixture when combustion occurs, producing blue smoke that can be seen in a vehicle's exhaust.