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What To Do If Your Lawn Mower is Blowing White Smoke

You just went out to mow the lawn, you turned on your mower, and white smoke is pouring out of it - now what?

What caused this fiasco and what can you do about it?

Fortunately, a smoke-blowing engine may not be a serious issue unless you don't pay attention to the smoke.

Here's a list of things you can do to if your lawnmower is emitting white or blue smoke:

White smoke is usually caused by excess fuel or oil burning and usually pretty simple issue to resolve.

If you've recently turned over or tilted the machine, a portion of the oil may have leaked out and started to burn, which creates white or blue smoke.

The best thing to do is to keep the engine running to burn off all excess oil - it shouldn't last for too long. If you turn off the mower engine that just means that once you start it again, it will start to smoke again.

The solution is the same for those times when you have overfilled the oil reservoir - just let it smoke and burn off the excess oil.

There are also times when white smoke isn't an occasional problem but is continual.  This can be more difficult to fix/diagnose.

The first thing to do is to examine the crankcase and check if there is an air leak. Air leaks will let more air into a mower's crankcase than necessary and will cause a greater quantity of oil mist than the breather of the crankcase can handle, which then results in too much oil being burned off.

If you're not able to find an air leak, and your lawn mower is malfunctioning, you will then need to pack up your mower and take it to a mechanic. They can determine if the white smoke is blowing out because of a blown head-gasket, worn rings or a worn cylinder, or because of a non functioning crankcase breather.

A professional mechanic will cost you a bit more money upfront, but will save you time and headache in the long run.  Angie's List is a good place to start if you don't have a shop in mind already.

To sum things up, white smoke emerging from your lawn mower is not a sure sign that it's broken.

Your mower might just need a bit of TLC.

Before you take that drive to the mechanic's place, take a little time to smell the smoke and note what color the smoke is.

Your problem might be as minor as having to buy a new inexpensive air filter, and not serious enough to require a significant expenditure on labor and parts.

This video may help you out as well:

Side Note: I am not a mechanic, so my suggestion is if you aren't comfortable digging into this issue, take your mower to a pro.

About the author

Matt Hagens

Hi, I'm Matt the owner of Yard Care Gurus. I love to be outside working on my lawn, planning my next project. I created this website to help people like you find the best products for yard care and great advice. Thanks for stopping by!

Cynthia - July 10, 2018

I have a Briggs Stratton yard machine. I’ve only used it 8 times and its smoking, the smoke is coming out the round aluminum circular thing and oil is coming from where the filter is located. I believe it was tampered with. What do I need to do?


    Mark Kelly - July 10, 2018

    It’s impossible for me to diagnose without seeing the machine. I would take it to a shop. It should still be under warranty if you’ve only used it 8 times.

      John Lennon - August 28, 2018

      yes ok

    Liam - September 10, 2018

    Cynthia, it sounds like your mower has been tipped wrong and oil has moved into the combustion chamber , it needs cleaning out and the oil level should be checked and the mower running until it clears, you may need the carb cleaning . I would replace the spark plug and air filter element.

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