Why is My Lawnmower Blowing White Smoke?

Your mower shouldn’t smoke white during use. The good thing is, though a nuisance, the problem has a very simple fix. Don’t ignore the white smoke as this could cause more harm to your mower and shorten its lifespan.

What Causes White Smoke from a Lawnmower?

A lawnmower will smoke white if it’s burning some oil that got into its cylinders by mistake. There’s a couple of things that could lead to such a mishap but the most common is when you tip your lawnmower to clean it or you have over-filled your mower with engine oil.

Your mower can also smoke white if:

  • A faulty crankcase breather
  • A worn out engine that is in disrepair
  • Head gasket failure
  • An overfilled oil reservoir

If you’ve been taking good care of your mower, chances are the oil got into your cylinders when cleaning the mower. Here is what you can do to clean up the mess before it affects your lawnmowing.

How to Stop a Lawn Mower from Smoking

The simplest way to solve this problem is by letting the mower burn off the stray oil. Ideally, the white smoke should dissipate after some minutes of continuous running. If it doesn’t dissipate in five minutes, you will have to drain the oil manually.

If you have too much oil, you can use an oil extractor to drain the excess oil. After draining, fire up the engine and let it idle for five minutes and see if the white smoke dissipates.

Lawnmower Smokes and Dies

Sometimes, your mower will startup, run while smoking white for a while, and then off. If this happens, trying restarting for a few times and see if that clears the oil.

Check this too: Best Lawn Mower For Hills And Steep Slopes

If the engine is not running long enough, you have to remove the spark plugs and remove all the oil from the cylinders. Remember to clean or replace the spark plug before trying again. If the white smoke persists, you might still have to clean your carburetor and get rid of any remaining oil.

Accidentally Putting Oil in the Gas

Another common cause of white smoke is accidentally putting the right lawnmower oil into the gas tank of a four-stroke mower. The result would be that dramatic white smoke. The solution is simple; drain all the gas and fill her up with new oil before running it on idle to clear the system. You might still have to clean the carburetor though.

A Faulty Head Gasket

A faulty gasket will always need more work. If you are not a great handyman who knows their way around engines, you will have to take your mower to a mechanic for fixing.

Remember to take good care of your mower. The wrong oil type, spark plugs or no servicing will make your mower more susceptible to white smoking.

1 thought on “Why is My Lawnmower Blowing White Smoke?

  • Thank you for posting the article. Currently having this issue, my lawnmower has turned into a fog machine.

    I believe I tipped it on the side to remove grass that was stuck in the blade. Could this have caused the issue?

    If I let it run for 5 minutes while blasting white smoke, is there a chance that this will harm the mower?

    Would love to hear back, thank you.

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