Lawnmower Repairs - Leaking Oil Throught The Muffler And Smoking. What Do I Need To Do?

This problem often occurs when people tip the lawn mower, in order to inspect the blades for example. You should always make sure that, if you have to tip the mower on its side, always do it with the carburettor up. Or tip it from the front.

What has probably happened is the oil from the crankcase ran through the crankcase vent tube to the carburettor air box. Now you have oil in the air filter. Remove and replace the air filter, remove the spark plug and clean it. Then check the oil level in the crankcase and add if necessary. You may have to put a little gas in the spark plug hole to get it to start and it will smoke a bit, however it should clear up.

Excessive smoke from the engine may also be an indication of problems with the carburettor, rings, or gasoline.

- Black smoke is a symptom of an overly rich fuel-air mixture. This could be caused by a choke that is partially closed, a faulty carburettor, or the need for a carburettor adjustment. Make sure the choke if fully open and proceed with the instructions outlined above.

- White or black smoke may also result from yard debris, oil, or other contaminants on the exterior of the cylinder as the temperature after a few minutes of operation will reach very high temperatures even with proper cooling. Stop the engine and let it cool for a few minutes. Then check around the cylinder, cylinder head, and under the shroud for grass clippings, leaves, oil or other spills, dead rodents, etc.

Exact same thing happened to me. Tilt mower backwards (so spark plug end is elevated - check wher it is) and drain oil from oil basin out (catch it in an old jar or something). I put in way too much (like 1/2 a cup - need 15-20 mls at most). Keep spark plug elevated for a while to drain overflow of oil back to where it should be. Start mowing, will still be some smoke, but will diminish very quickly. After about 2 minutes it should no longer be smoking.

Take it out back and shoot it.