Self-Propelled Lawn Mower Leaking Engine Oil

There are several places that a self-propelled lawn mower can leak oil form. The most common of those places is from the carburetor. Yes, the carburetor. When you overfill the engine oil, it will be sucked into the crankcase breather and then into the breather tube and into the carburetor. Then that oil will drip out of the carburetor and it can also get ingested into the engine and burned up. This will also cause the engine exhaust to burn a light blue color.

Another place is the rocker arm cover. The seal can become split or the bolts holding the cover on can loosen and cause the cover to leak. First, check the bolts to see if they are tight and if they are, check the integrity of the seal.

Oil can also leak at the crankshaft seals. There is a seal at the bottom of the engine and the top is sealed by a tight fit between the crankshaft and the crankcase.

The last place is at the crankcase itself. An item such as the governor arm protruding through the case or the crankcase gasket itself will leak.

Now that you know where the majority of leaks occur from on a self-propelled lawn mower engine, you can find a small engine repair shop near you on our Locations page.

Lawn Mower has Blue Smoke Coming From Exhaust

The infamous blue smoke coming from the exhaust is a sign of burning oil. You can also verify this by removing the spark plug. You will see a shiny black or gooey appearance on the electrode side.

Now you may have simply overfilled the engine with oil so that is the first place to start. Remove the dipstick, wipe it off and then re-insert. Pull it out and then check the level. On Asian brand engines, you do not need to screw the dipstick into the case, simply dip it in and put it back out.

If the oil level is fine, then something internal may be causing the problem. You could have a blown head gasket, a bad breather valve, your piston rings are worn or the oil seal for your intake valve is bad.

These are items that would be best diagnosed by a lawn mower engine mechanic as they have the proper tools and information to do these tests. You can find a lawn mower shop near you by visiting our Locations page. Let them know the symptoms of your lawn mower engine problems and give them as much information as you can to assist with the proper diagnosis.