If the lawn mower smokes black - it could be

If the lawn mower smokes black - it could be

Cause: Sooty spark plug

The top 3 most common causes of black smoke include sooty spark plugs. The more dirt particles accumulate on it, the more intensely it smokes. If you do not intervene now, the lawnmower will ultimately not start at all. How to solve the problem:

  • Turn off the lawn mower and let it cool down
  • Remove the connector from the spark plug
  • Unscrew the spark plug with the spark plug wrench

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Now clean the spark plug and contacts with a brush and rag. Please do not use water or liquid cleaning agents for this purpose. Then put the clean spark plug back in and put the connector on it.

Cause: Clogged air filter

Black smoke is a typical symptom of a dirty and clogged air filter. If you can identify this component as the culprit, either cleaning it will fix the problem or you can change the filter. The operating instructions for your lawnmower tell you how to remove the air filter.

If it is a paper filter, you can knock out the dirt or blow it out with compressed air. Foam filters can be cleaned very easily with warm water and dishwashing detergent.

Cause: Dirty carburettor

If you think that a dirty carburetor is the source of black smoke, you do not necessarily have to remove the component. With a little luck, the problem can be overcome with the following emergency aid program:

  • Pull out the spark plug connector
  • Drain gasoline from the tank
  • Pull off the line between the tank and the carburettor and clean it

Use a carburetor cleaner to spray all accessible nozzles, throttle valves and the entire housing. The spray not only loosens dirt deposits, but also grease, oil and resin. We also recommend changing the oil. Put the mower back together and do a test run. Experience has shown that black smoke no longer rises.


If a lawnmower smokes blue, the cause is oil leakage. Carefully check the oil level. Spilled gasoline is also a possible trigger. White-blue smoke rises just as often if you previously tilted the lawnmower in the wrong direction for cleaning.