My lawnmower has oil in air filter.

Question

It is causing it to smoke and lug. Can I just change the air filter without any other maintenance?

Answer 1

This is usually caused by either tipping the mower on it's side or putting too much oil into the crankcase.  You can change the air filter at any time.  Check the oil level and make sure it is not above the full mark on the dipstick.  

Answer 2

Depends how the oil got into the air filter?

If it was just from being turned upside down, sure replace the filter check the oil and carry on.

But if you don't know how the oil got in there, well you have some investigating to do.

Answer 3

Oil over filled, mower has been tipped over, cylinder blow by (due to wear) or if it is a overhead valved engine, a blown head gasket