Why is the Lawn Mower Blowing White Smoke? (3 Solutions)

A large cloud of white smoke can be frightening. Most people don’t expect it to happen, so why is it happening at all? What does lawn mower blowing white smoke means?

What is causing your lawn mower to emit white smoke? The truth is that it could be for one of the following reasons:

  • Your crankcase has an air leak.
  • An overflowing crankcase
  • In your crankcase, you may have a broken or non-functioning breather.
  • Oil of poor quality
  • If you leaned the engine more than 15 degrees (even if just for storage)
  • If your cylinder is worn out, replace it.
  • The head gasket had failed.

Of course, simply understanding what caused your lawnmower to emit white smoke is insufficient; you must also understand how to repair it. So, if you want to learn more about these issues (as well as some other issues that could be causing white smoke), as well as the solutions, keep reading.

Why is My Lawn Mower Blowing White Smoke?
Why is My Lawn Mower Blowing White Smoke?


White smoke could be harmful or beneficial. The good news is that you’ll find out soon enough which one it is. The presence of white smoke indicates that the engine is burning oil.

This is usually the result of a spill or an unintentional overfilling of the crankcase. The smoke should clear up and your mower should operate normally once the trace oil that has reached the engine has been burned off.

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When a new mower is started for the first time, it will also emit white smoke. There is frequently oil residue left by the manufacturer, and running the mower to burn off the oil solves the problem.

However, if your mower continues to emit white smoke in either case, you’ve got a bigger problem on your hands. The oil has found a way into the combustion chamber. A ruptured breathing tube, a blown head gasket, or a worn seal are all possibilities. Whatever the case may be, you’ll require lawn mower repair in Ogden, UT.

Alternative Video: White Smoke Coming From Lawn Mower – How To Fix

White Smoke Coming From Lawn Mower – How To Fix



As previously stated, there are several common reasons why your lawn mower may be emitting white smoke. It happens frequently — much more frequently than you’d think — and the majority of these issues are simple to resolve, but more on that later.

For the time being, let’s just look at all of the possible causes of your lawn mower blowing white smoke. Some of them were already mentioned at the start of this article. They are as follows:

  • The most common cause of white smoke coming from your lawnmower is a tilted engine (no lawnmower should be tilted at an angle bigger than 15 degrees).
  • Oil issues, such as overflowing oil or the incorrect type of oil, are the second most common cause, and they are frequently very simple to resolve.
  • Leaks are another common problem, and if left unchecked, they can cause even more problems.
  • Broken parts, such as the head gasket and cylinders, must be checked on a regular basis to avoid these problems.

Other than these, there are some less common causes, but it’s good to be aware of them in case you’re one of the people affected. They are as follows:

  • obstructing the breather
  • Adding more oil than the dipstick indicates
  • Piston rings that are damaged

Fortunately, all of these are simple to fix. There is no room for fear. First, turn off your machine and allow it to cool down. Then you can move on to some possible solutions.


While white smoke appears to be a serious problem, it is not. If you just follow a few simple steps, you’ll be able to fix it in no time. Naturally, you may not know what caused the smoke right away, but it doesn’t hurt to try some of these solutions until you get it right.

Lawn Mower Blows White Smoke
Lawn Mower Blows White Smoke


Starting with the most basic cause of white smoke in lawn mowers, which is also the simplest to repair. You’ll also know right away if this is the cause. Has your lawn mower been tipped more than 15 degrees? Maybe you stored it that way, or maybe you moved it that way by accident.

The majority of people encounter this problem while cleaning under the deck or emptying the chute. When they do this, the oil moves from the crankcase to the cylinder, and your lawnmower begins to smoke when you restart it. In some cases, the oil will also leak.

The best solution is to turn the lawnmower upside down, check the oil in the crankcase (add more if necessary), and then run the engine until the smoke goes away. It’s a straightforward solution, though the smoke may make your neighbors uncomfortable.

However, if you have a tractor mower, this is unlikely to be the case, so you must look for other causes.


In general, your lawnmower will require slightly more than a pound (near 0.5 liter) of oil. This is a very small amount, so it’s not surprising if you occasionally overfilled the crankcase. It’s quite common. To avoid this, simply double-check the level and amount before proceeding with the mowing.

People frequently believe that a little oil can’t hurt anyone, especially the lawnmower, but the truth is that it can be extremely damaging to the engine. Most engines use a splash lubrication system, and if the oil level is higher than the paddles, the engine will not function properly.

In this case, the engine is producing white smoke because it is attempting to burn through all of the oil. You can quickly fix it by draining the oil and then running the engine until the smoke has gone away. It’s a quick and easy fix, just like the first cause of white smoke.

While extracting the excess oil can be time-consuming, especially on some models, you should do your best because it will speed up the process.

However, if the oil smells like gasoline, you should not start the engine. This indicates that your carburetor seal has failed. In this case, you should repair the carburetor and then change the oil before resuming use of the machine.

If you try to start the engine without adding proper oil and repairing the problem, the engine may be damaged because the oil is too thin (because of the gas).

Another possibility is that the oil has made its way to the carburetor, preventing the gas from reaching the jet. You’ll be able to spend that oil if you run the engine a few times, and the smoke will go away. If it doesn’t seem to be working, you should clean your carburetor.

For starters, you’ll have to start your engine and then spill the oil. You can then replace the plug and try again. There are more detailed cleaning procedures for the carburetor, but try them after you’ve tried this because it’s simple and may just solve your problem.

You could also accidentally put oil in the gas tank, which is a common blunder. Simply drain the oil and replace it with gas to repair it. After that, run the engine for a few minutes to clear out the remaining oil and remove the smoke. You could clean the entire carburetor once more.

How To Fix My Lawn Mower Blowing White Smoke?
How To Fix My Lawn Mower Blowing White Smoke?


If your head gasket fails, you will most likely see a lot of smoke. It’s also less common, but it’s still possible — and more difficult to fix.

A head gasket is a component that is installed between the cylinder head and the cylinder block of an engine to seal the area where combustion occurs. Other than white smoke, common symptoms of this problem include oil leaks, increased crankcase pressure, strange noises, and so on. To repair it, you must replace it.


When a lawn mower blows a head gasket, it immediately emits SOS signals that allow you to diagnose its current condition. Let’s look at the three most common symptoms.

1. The Exhaust Produces Smoke

When black or white smoke begins to rise from your lawn mower’s exhaust, it is usually the result of a blown head gasket, which may indicate problems with the mower’s combustion system. Worn or damaged gaskets are simple to replace and should be replaced as soon as possible to avoid further problems.

2. The Motor Constantly Shuts Off

A faulty head gasket can cause the mower to drop out and shut down unexpectedly. When you turn a corner with the mower, this may be common. Low pressure in the motor’s combustion chamber is frequently the result of a worn or damaged gasket. In that case, the gasket must be replaced.

3. The Engine Keeps Leaking Oil

When the engine constantly leaks oil, this is another sign of a blown head gasket. If you notice that you are replacing the oil in your engine more frequently than usual, it is likely that it is leaking from a damaged gasket. You can inspect the gasket for wet or dried oil around the edges. If this is the case, the gasket will need to be replaced.


White smoke can be alarming, but it’s usually a simple fix. Blue or black smoke is far more hazardous to your lawnmower. When it comes to white smoke, it’s simply a matter of resolving a minor issue and letting the engine run until the smoke disappears.

Remember that new lawnmowers tend to blow white smoke for a while until they get going and adjust to everything. So, if you see this on your first mowing round with your new mower, don’t be alarmed.

How to Stop a Lawn Mower from Smoking White?
How to Stop a Lawn Mower from Smoking White?

Frequently Asked Questions

What happens when you put too much oil in a lawn mower?

Too much oil in your lawn mower’s engine can cause it to overheat and cause damage. Too much oil in your engine can cause it to overheat, resulting in seal damage, blown gaskets, or becoming hydrolocked.

Can too much oil in a lawn mower cause white smoke?

When too much oil enters the crankcase of the lawn mower, the oil sump overflows. The operation of the crankcase will be hampered by an overflowing oil sump. As a result, signs of too much oil in a lawn mower include oil splatters all over the muffler, white smoke from the muffler, and a difficult start.

Can lawn mowers explode?

If a lawn mower catches fire or unauthorized changes are made to the fuel supply or engine, it is likely to explode. When used properly, the chances of a lawn mower exploding are almost non-existent.

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