how to fix a smoking lawn mower

Is your lawnmower going up in smoke? Not literally, but is your lawnmower emitting different color smoke, and you can't figure out what each color means! Well, here's the lowdown on what different color smoke means, and how to fix the issue yourself or get professional help.

First things first, and regardless of the color, smoke emitted from your lawnmower is a sign of concern, and may require professional help. On a brighter note, blowing smoke is not an indication of a serious issue with your lawnmower, but can turn into one if left unattended.

Quick Troubleshooting Steps

First, check the air filter and replace it if dirty.
Next, check the oil level. Fill with proper oil grade if necessary.
Then start the mower and let it run for 5-10 minutes to burn off any oil that may have found its way to the engine.
Also, mowing at step angles for a long period could cause smoke as there could be oil leakage. Make sure caps are fully secure.

Keep reading for different smoke colors as each has its own set of issues.

Smoke from lawn mowers are typically one of 3 colors:

Black Smoke
White Smoke
Blue Smoke

I'll go over each color below along with some suggestion solutions you can try right now and possibly avoid a trip to the lawn mower repair shop.

What does Black Lawn Mower Smoke Mean?

Black smoke from your lawn mower in most cases means your carburetor and fuel systems aren't functioning properly. These aforementioned systems are responsible for regulating the ratio or gasoline to air mixture, and when the carburetor doesn't get enough air, the fuel mixture will be too rich, resulting in a higher percentage of gasoline.

Or, black smoke coming out of a lawn mower means that the ratio of fuel to air is incorrect, which is usually caused by a dirty or worn-out air filter. To clean the air filter of the lawn mower, remove it and clean with soapy water or replace with a new one by referring to your owner's manual.

Solution – If your lawn mower is creating black exhaust smoke, the first thing you'd want to check is the onsite air filter. Great chances are that the air filter may be clogged, and is blocking sufficient air flow to the carburetor.

Since all models vary by brands, it's important that you refer to your owner's manual on how to clean the air filter. But generally, you have to remove it, clean it or replace it if it's clogged.

After you've cleaned the air filter or replaced it, start your lawn mower, and let it run for a few minutes to see if the issue has been fixed. If the black smoke issue still persists after cleaning or replacing the air filter, then it may be your carburetor acting up, so you will have to make a couple adjustments.

Even though this step is just a matter of adjusting a screw or two by referring to your owner's manual, your best bet is to have it looked at by a professional or better yet the manufacturer if your lawn mower is still under warranty.

What does White Lawn Mower Smoke Mean?

White is the most common color of lawn mower smoke, and most of the time will go away on its own. But if it doesn't, there're a good indication that you've got an overfull oil reservoir. An overfull oil reservoir will cause the engine to burn oil, which can be caused by one or more reasons.

These include spilling oil on the housing when you serviced the lawn mower and tilted it too much, or simply overfilling the crankcase.

An overfull lawn mower oil reservoir can also be caused if you mowed on a 15-degree incline, overfilled the gas tank if you have a 2-stroke mower (the correct ratio is 32:1 gasoline to oil ratio), or it's a new mower with leftover oil residue.

Solution – as mentioned earlier, the white smoke issue will go away on its own if you leave the lawn mover running for a few minutes, as this runtime will burn off the excess oil. If the white smoke isn't gone after running your lawnmower for roughly 15 minutes or so, you may have a bigger issue to deal with.

The first issue may be that the seals of the combustion chamber have worn out, causing the oil to leak into it. Another reason may be an air leak in the crank case, or that both the cylinder and rings have worn out.

A serious reason for white lawn mower smoke will pertain to a malfunction of the head gasket, and will more than likely need professional attention. However, there's no need to break a sweat just yet, but check if your lawn mower is still under warranty, and if it is, get it looked at by your nearest servicing dealer.

My Lawn Mower Is Blowing Blue Smoke, What Does This Mean?

The causes of blue smoke emitting from the exhaust of your lawn mower are pretty much the same as white smoke. These include overfilling the crankcase, or spilling oil on other parts of the mower when filling the crankcase.

Blue smoke can also be caused if using the wrong oil grade, or if you've tilted the lawn mower too much when mowing a ditch or hill, so make sure to keep the spark plug tilted if angled mowing is necessary.

Here is a great video from Steve's Small Engine Saloon

You Won't Believe What's Wrong With This Lawn Mower

Final Thoughts

Having a smoking lawn mower is never fun for the operator or for your neighbors, so addressing any smoking issues you have when you first notice it is key. It will help your mower last much longer plus your neighbors and your lungs will thank you.

You may also want to opt for non-gas mowers such as reel mowers or corded electric mowers.

If you have any specific questions about your mower, please leave a comment or question below.

Hi, Alex Kuritz. here. Growing up I remember that my family had one of the best lawns in the neighborhood. Richly green and lush. I did a lot as I grew up in terms of caring and tending for not only my family's lawn but also my neighbors. I can say I have years of experience, and I am here to share it with you.
Please leave your comments below as I try to respond to everyone that has questions.

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