If a lawnmower emits black smoke, the cause is not obvious at first glance. This guide accompanies you through the root cause analysis with practical tips on common sources of errors and effective countermeasures. This could be the reason why a lawn mower emits black smoke.
Why does my lawnmower smoke black?
If a lawnmower emits black smoke, the causes could be a sooty spark plug, a clogged air filter or a dirty carburettor. To resolve this, clean or replace the spark plug, air filter and carburetor if necessary.
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 don't take action now, the lawn mower will ultimately no longer start at all. How to get rid of the problem:
- Turn off the lawnmower and let it cool down
- Remove the connector from the spark plug
- Use the spark plug wrench to remove the candle
Now clean the spark plug and contacts with a brush and cloth. Please do not use water or liquid cleaning agents for this purpose. Then reinsert the clean spark plug and place the plug 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 solve the problem or you can replace the filter. Your lawn mower owner's manual will 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 carburetor
If you suspect a dirty carburettor is the cause of black smoke, you don't necessarily have to remove the component. With a little luck, the problem can be solved with the following emergency aid program:
- Pull the spark plug connector
- Draining gasoline from the tank
- Detach and clean the line between the tank and carburettor
Use a carburettor cleaner (€8.00 on Amazon) to spray all accessible nozzles, throttle valves and the entire housing. The spray not only dissolves dirt deposits, but also grease, oil and resin. We also recommend an oil change. Reassemble the lawnmower and do a test run. Experience has shown that black smoke no longer rises.
Tip
If a lawnmower smokes blue, leaking oil is the cause. Check the oil level carefully. Spilled gasoline is also a possible trigger. Just as often, white-blue smoke rises if you tilt the lawnmower in the wrong direction for cleaning work.