Causes of White Smoke From Lawn Mower & How to Stop A Lawn Mower From Smoking

Causes of White Smoke From Lawn Mower

For our lawn to look good, we need to put it through a system that includes regular maintenance for our lawn to look good. To do this, we need a good lawn mower that can give you evenly mowed lawn once you are done. Similarly, you need a mower that is more than capable of handling the kind of terrain you are in. But just as we take good care of our lawn, we need to take equal care of the lawnmower. Like every other appliance, the lawnmower needs to be subjected to regular maintenance. 

Not doing so can hamper your mower’s durability. One of the most commonly reported problems is a lawnmower blowing white smoke. Smoke from a lawnmower is never a good sign, especially if you have a mechanical machine that runs on gasoline. In comparison automowers such as the automowers Husqvarna 115H & 315X rarely smoke, however, even a small level of smoke is enough to light your entire lawn on fire. So, if you notice your lawnmower blowing white smoke, then it needs to be addressed immediately. 

Therefore, this article will walk you through the various causes of white smoke from lawn mowers and how to stop a lawnmower from smoking. 

Blue, Black and White Smoke From Lawn Mowers | What Do They Mean

As we mentioned, smoke from a lawnmower is never a good sign. Generally, the only smoke a lawnmower emits is a white one. However, it can at times emit blue and black smoke as well. If your lawnmower emits blue, black, or white smoke, here is what they mean

1. Black Smoke From Lawn Mower

Having your mower emits black smoke is not a bad sign. Although the small looks deadly in appearance, it does NOT mean your mower needs any repairs. Black smoke is generally the result of the fuel and air mixture. This mixture is blocked in case there isn’t enough oxygen available for combustion, which is why the unburned fuel in the gas chamber emits black smoke. Your lawn mower generally emits black smoke if you are located in closed spaces without ample oxygen availability. 

2. White Smoke From Lawn Mower

White Smoke From Lawn Mower

Your mower emitting black smoke could either be bad or okay. If you notice white smoke from lawnmower, then it means that the engine is burning oil, which could result from a spill or an accidental overfilling of the crankcase. Once the oil reaches the engine, it will automatically burn off the white smoke will be cleared. Generally, new mowers tend to emit white smoke in the initial stages.

The problem will be solved automatically once the engine burns off the excess oil. However, if the white smoke continues to persist for a while, it means that there is either a rupture in the breathing tube, a blown head gasket, or a worn seal.

3. Blue Smoke From Lawnmower

Blue smoke From Lawn Mower

You don’t want your lawn mower emitting blue smoke. Blue smoke is a problem as it indicates oil seeping into the combustion chamber. Unfortunately, there is nothing you can do if the lawn mower emits blue smoke. We recommend you call a technician at once and have them look at the machine. 

Why Is My Lawn Mower Smoking White?

As mentioned above, white can be a cause of concern as it generally indicates that the engine is burning oil. The mower will return to normal once the engine has completely burned off the excess oil. However, if the white smoke continues to persist, then it generally is either a rupture in the breathing tube, a blown head gasket, or a worn seal.

While smoking is primarily the result of excess oil or oxygen present in the gas tank. An overfull gas reservoir will generally make the engine burn off the excess oil. In addition to all this, here are some of the possible reasons why there is white smoke from lawn mower

  • Air Leak In the Crankcase
  • Overfilled Crankcase
  • Broken Crankcase
  • Poor Oil Quality 
  • Engine Tilted Over 15 Degrees
  • Worn Out Cylinder
  • Broken Head Gasket

How to Stop a Lawn Mower From Smoking?

Leaks are quite common on every appliance that runs on gasoline or oil or other forms of fuel. However, these leaks can turn lethal if not addressed immediately. Similarly, smoke from a lawnmower is a concern that needs to be addressed immediately. Above are some of the most common causes for your lawn mower blowing white smoke. Fortunately, all these are very easy to repair. 

NOTE: Before you move on to implement the fixes, turn off your machine and let it cool off for at least two hours. Ensure that the machine is turned off when implementing fixes. Always wear protective gear such as safety goggles, earplugs, and protective gloves when fixing the machine. Do NOT touch the mower blades with your bare hands. 

1. Oil Issues

Oil issues are fairly common in machines operating on fuel. As we mentioned countless times throughout the article, white smoke is generally the result of excess oil present in the gas compartment. Most modern-day lawnmowers tend to hold a little over 0.5 liters of oil.

This can lead to you overfilling the crankcase every once in a while. Since the quantity is too small, we generally overlook the excess oil present. But even a small amount of excess can cause your mower to emit white smoke. A simple solution to all this is to check the oil level after filling the oil and alter the quantity if necessary.

Most people think that a little oil over the top won’t be a problem. However, they fail to realize that this could be hazardous to the engine. Since most mowers work on splash lubrication, having the oil level higher than the paddles can hamper the engine’s overall functioning.

If you notice extra oil within the machine, try removing the oil any way you can. While doing so, check for the smell. If your oil smells like gas, it indicates that the carburetor seal is broken, so you should REFRAIN from using the machine. In this case, change the carburetor first and then change the oil in the machine. Use this guide to learn to locate the carburetor on your lawn mower.

NOTE: You need to add the precise amount of oil required for normal functioning. Having oil below or above the required level will hamper the mower’s functioning. 

If you want to remove the excess oil, simply tip over your mower and try to remove as much oil as possible. Meanwhile, if you have accidentally put the oil in the gas tank, drain the oil and replace it with gas. Start the engine and keep it running for a few minutes till the engine burns off any oil present and the white smoke has disappeared. 

2. Lawn Mower Tipped Over

Lawn Mower Tipped Over

This is one of the primary causes for your lawn mower blowing white smoke. In addition, if the mower is tipped over for more than 15 degrees, oil begins seeping into the engine, causing white smoke. Check whether the lawnmower is tipped over at an angle greater than 15 degrees to cancel this out. This generally happens while cleaning under the machine’s deck or while emptying the chute. 

If you think the tipping angle is over 15 degrees, make sure you return the mower to its normal position to avoid your lawnmower blowing white smoke. This is because tipping your machine over 15 degrees causes oil to seep into the cylinder from the crankcase, causing your mower to smoke when started and in the worst case, your lawnmowers can even catch fire.

The best solution for this is to get your mower upright and check for oil in the crankcase and add more oil only if necessary. Once this is done, start your engine and let it run until the white smoke has disappeared. The white smoke will disappear once the engine has burned off the excess oil.

3. Head Gasket Issues

The lawnmower will stop emitting white smoke once the engine drains and burns off the excess oil present in the gas tank. However, if the smoke persists, it could mean a blown head gasket. If the gasket is broken, then you have a lot of smoke headed your way.

Although this is a rarely arising issue, it is equally difficult to fix. The head gasket lies between the cylinder head in the engine and the cylinder block. The head gasket is responsible for sealing the area in between and allowing for combustion to take place. In case of a broken gasket, your only solution is to replace it with a new one and then fill the oil in the engine.

NOTE: Do Not Run The Engine If You Have A Blown Or Leaky Gasket. Call In An Expert And Have The Gasket Replaced At Once. Do Not Try To Fix The Gasket Manually

4. Failed Piston Rings

Failed Piston Rings

Another common reason for your lawn mower blowing white smoke could be due to failed piston rings. But of all the possible reasons, a failed piston ring is perhaps the worst one. This generally happens if you have an old worn-out mower at your disposal or have a mower with extremely poor maintenance.

Piston rings are responsible for draining the excess oil from the combustion chamber and flowing it back into the engine block. But this operation is hampered if the piston rings fail. When the piston rings fail, the oil in the combustion chamber continues to pile up, due to which you notice your lawnmower blowing white smoke. 

If the piston rings have failed, the best thing to do is to rebuild the engine completely. Unfortunately, if the piston rings have failed, then your head cylinder is likely to be damaged as well. This means you will need to replace the piston rings along with the head cylinder. To do so, always call in an expert and have him do the job. 


Smoke is an integral part of every appliance that relies on oil and gas combustion for functioning. Having smoke come out of your mower isn’t always a bad sign. However, if there is colored smoke coming out of your lawnmower, it can be a cause of concern. Colored smoke is generally an indicator that your mower is in desperate need of repair. If you have smoke coming out of the engine, you can use this troubleshooting guide to fix the problem yourself. However, if the smoke persists, we strongly recommend you call a professional for help. 

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