Why Is My Lawnmower Blowing White Smoke – Beginner’s Guide

First things first – if your lawnmower is blowing smoke, irrespective of its color, there is clearly something wrong. In this article, we focus on the occurrence of white smoke in particular which happens to be emanating from your lawn mower.

Once you know the reasons behind the emission of this white colored smoke, you will in turn be in a good position to resolve the problem.

Therefore, without further ado, we get down to answering your question as to “Why is my lawnmower blowing white smoke?”


Don’t Panic!

why is my lawnmower blowing white smoke

Now, before we give you a thorough background on the reasons for which white smoke could be billowing out of your lawn mower it is really important that you DO NOT panic.

Remain calm; irrespective of the reasons, for which your lawnmower may be blowing white smoke, they are all easily addressable. Therefore, sit back while we examine each of those reasons.

Over Enthusiastic Cleaning

One of the most common reasons for which lawnmowers end up blowing white smoke while operating them is because you went a little overboard with your cleaning regimen. This is especially true when you tip your lawn mower over so that you could thoroughly scrub its deck while also unclogging its chute which may have got blocked.

Now, in this entire process, there is every chance that oil ended up getting into the cylinder. Once your cleaning regimen is complete, once you fire up your lawn mower, this oil will start to burn, thus causing the white smoke that you see.


Well, the solution lies in avoiding tipping your lawn mower while cleaning. We understand that this can be hard. So, the right thing for you to do would be to tip it carefully, applying adequate caution such that oil does not end up entering the cylinder.

Other Situations where Oil Enters the Cylinder

While excess cleaning is definitely one of the most common reasons for which oil ends up entering the cylinder, it is definitely not the only one.

Another frequently observed scenario is while mowing uphill. Due to the resultant trajectory, oil frequently enters the cylinder in such cases, especially if you have been mowing uphill for a while.

Herein, the solution would simply be to assess the elevation at which you have been mowing, in case you observe white smoke blowing from your lawn mower.

Video on White Smoke Blowing from Lawn Mowers

While we are on this topic, a video which we recommend you check out on white smoke blowing from lawn mowers:

Excess Engine Oil

Another common reason for which you might notice white smoke blowing out of your lawnmower is when you’ve filled in way too much engine oil into it. This often happens in case of tractor mowers although it can be the case with any type of lawnmower.

The solution in this instance would of course be rather elementary, viz. you take adequate caution while filling engine oil into your lawnmower so as to not go overboard. Most lawnmowers anyway have specifications about the amount of engine oil which is to be put into them; make sure you abide by them. Further, those levels are indicated on the lawnmowers themselves, making it even simpler for you to ensure that you do not fill in excess engine oil.

Problem in the Carburetor

Another reason you are likely to see white smoke blowing out of your lawn mower is because there is a problem in the carburetor. These problems could take the shape of:

  • Gas mixing up with the oil in your lawn mower
  • A carburetor which is damaged, clogged, or generally in a state of disrepair

No matter which of these is the trigger behind the carburetor issues in your lawn mower, it can easily be fixed.

In the first problematic scenario, if gas is mixing up with the oil in your lawn mower, then the issue is quite likely in the carburetor seal. This can either be repaired or replaced, depending on the extent of the problem. Bear in mind that once you have done the needful, you will have to change the oil in your lawn mower as well since in its current form, it won’t be usable.

Further, if your carburetor is blocked, you can clean it yourself. If you are wondering how to go about doing so, you can easily take the help of many guides and tutorials available online at no charge.

Likewise, a carburetor which is way too damaged clearly requires replacement with a new one. Again, you will find the process of replacing with a new carburetor rather easy.

Incorrect Grade of Oil

When it comes to engine oil in just about any machine – such as your car for example, the grade of oil put into it really matters. In case of lawn mowers for example, there are very specific oil grades that you can use on them.

Moreover, within lawn mowers, the type and make often determines the oil grade to be used.

Incorrect grade of oil can possibly lead to the emission of white smoke when you run your lawn mower.

Therefore, the solution is clearly to use the correct engine oil grade. This would be specified in the manual and/or packaging of your lawn mower.

Blown Head Gasket

A common reason for white smoke to emanate out of your lawn mower is the head gasket being blown away. This is especially true if you find that your lawn mower refuses to start after emanating white smoke.

In this case, a simple act of replacing the head gasket should do the job.


Finally, there is the possibility of moisture entering key areas of your lawn mower, especially fuel compartments. This can often lead to white smoke blowing from your lawn mower.

Operating your lawn mower in the rain can lead to moisture getting into it. This can also happen while you are giving your lawn mower a thorough clean. Moisture can also accumulate on its own, in humid conditions.

While there is no clear solution per se, you simply need to check for this, in case of white smoke blowing out of your lawn mower and then suitably remove this accumulated moisture.


As you can see, there are myriad arrays of reasons for which your lawn mower can blow white smoke.

Therefore, the next time you happen to find yourself wondering as to “Why is my lawnmower blowing white smoke?” think of all the reasons we have highlighted above.

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Alongside, if you have any further questions or comments, do drop them below!

Tom Rico

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