Mower with oily fouled spark plug

Question

My mower would not start. On inspection of the spark plug there was wet oil present on both the spark plug and on the thread on the mower.

What maintenance and parts should i inspect/replace in order to fix this problem?

This will be my first attempt at servicing, or for that matter, taking apart a lawn mower. I have not been able to find videos specifically on this problem.

This mower is two years old, and has a 4-cycle engine. The oil level is correct and looks clean. I suspect the problem has come from running too rich; most probably by slowing the mower while i empty it. So in future I will just keep the mower running at full speed.

Answer 1

Replace the plug, and if you use the mower a lot, replace the air filter. If you let it warm in the sun a while before attempting to start, starting will be easier.

Answer 2

Is this a 2 cycle or a 4 cycle engine? I believe that all mowers sold in the last several years are 4 cycle, so you should not be mixing oil in the gas and significant oil on the spark plug would indicate leaking O-rings. Of course, if you haven't changed the spark plug in two years, it could easily be normal buildup, in which case, it's time to change the plug.