Can a Lawn Mower Explode? – Myth vs. Reality

As with most heavy-duty machinery or power tools, a lot of things can go wrong, which can lead to potential fire and explosion hazards.

Anyone new to this knows that working near motors and engines can feel a little intimidating. And lawn mowers are not an exception.

Lawn mowers are big and noisy, and it is not too much of a stretch to wonder whether they can explode or not.

So, can a lawn mower explode? Lawn mowers can explode as a result of catching fire or unauthorized changes and modding of the engine and the fuel system. Under normal use, chances of a lawn mower exploding are very low, but this can be further prevented by regular maintenance and service.

I too, had the same worry when I first started using a lawn mower, and while doing my research on the topic, I stumbled upon a lot of interesting details and facts.

If you want to know more, make sure to check out the rest of the article as I share everything I have learned about the hidden dangers of lawn mowers.

What Can Cause a Lawn Mower to Explode?

One of the main ways a lawn mower can explode is by catching fire, poor maintenance, or after unauthorized changes made to the machine.

Can a Lawn Mower Catch Fire?

Every kind of mower (battery-powered, electric, gas) can catch fire, given the right conditions.

To better understand the risks we are facing while working with a lawn mower let’s take a look at what situations can cause a lawn mower to catch fire.

The Grass Clippings

Regularly cutting the grass low is recommended not just because it is good for the grass but also because tall grass can be hazardous.

In fact, grass may easily be considered the number one cause for mowers to catch fire.

The big clippings of the cut grass can get over and above the lawn mower and come in contact with the hot motor, muffler, and other components, which then can catch fire and start burning.

Foreign Objects Collisions

We all know that it is recommended to cut your lawn when the grass is dry.

Although this is true, it can also cause us some problems.

The spinning steel blade(s) of the lawn mower can hit a rock or other metal objects that may have been left on the lawn, and this can produce sparks. If these sparks get in contact with any dry leaves or grass, this can quickly start a fire.

The Weather Conditions

During the summer, when the temperatures can get super high in some regions of the country, you may have to avoid mowing the grass in the noon and in the afternoon.

In these conditions, you will find mowing the lawn during the morning or the evening the most favorable. Otherwise, you are risking overheating your lawn mower, and in combination with the super dry grass, this can be a recipe for trouble.

If you have no other choice but to mow the grass at noon, it is recommended to take some safety precautions. For example, you can spray some water to damp the lawn a bit. Not too much though, because that would cause other problems (check out this article I wrote about mowing wet grass to learn more).

The Fuel and Oil

The next point of concern is in connection to the fuel and oil inside the lawn mower. These are the most highly flammable and hazardous substances found in the mower and should be handled with the utmost care.

Accidental oil and fuel spillage can lead to a fire. Gas has a low flash point, and the motor of the lawn mower can be a lot hotter than that.

If you are refueling your lawn mower, make sure that it has had time to cool off, as spilling fuel over the hot parts of the mower can be a potential fire hazard.

If you spill fuel on the grass or other surfaces, don’t run the mower over the areas where the fuel is. Let the fuel evaporate first before mowing these patches of grass.

Not Cleaning the Deck

Last but not least I’d like to point your attention to another aspect which can cause us a lot of trouble. Namely – not keeping the lawn mower deck clean.

While you are cutting the grass – and especially wet grass – the grass tends to accumulate underneath the mower deck. This will lead to difficulty cutting, higher stress on both the engine and the blades, which can cause the lawn mower to overheat.

Combine that with some of the other favorable conditions, and you have a fire hazard waiting to happen.

Other Ways a Lawn Mower Can Explode

As I mentioned earlier, although the number one reason a mower can explode would be as a result of fire, some other things may cause an explosion too.

Unauthorized tinkering and changes to the motor, carburetor, and fuel system can cause a lawn mower to explode in some cases.

For example, disconnecting and not connecting back the carburetor governor system can make the engine running at higher speeds than normal; as a result, it can overheat and potentially explode.

This is why if there is something wrong with the mower, it is advisable to always have it repaired by an authorized service – unless you really know what you are doing.

Is the Lawn Mower Blowing Smoke Dangerous?

If your lawn mower is blowing smoke, it may not necessarily mean that something bad is happening. Let me explain.

The color of the smoke can give you a few hints on what is causing it, for example:

White or Blue Smoke

White or blue smoke is a sign that the oil is burning with the fuel. Usually, the oil may have gotten to the crankcase or the motor. Overfilling the crankcase can be another reason for the white or blue smoke.

White smoke can happen if you accidentally spilled a little fuel mixture over the motor, and as it burns due to the heat, it will release white or blue smoke.

New lawn mowers may produce white smoke – this is normal, as this is caused by the burning oil residues applied to the motor by the manufacturer.

And last but not least while cleaning the deck and tilting your mower to the side or mowing on hills, small amounts of oil may have spilled into the combustion chamber, which can cause white or blue smoke to come out.

Blue smoke can also be an indication of a clogged breather, dirty air filter, seal leakage, and more.

Black Smoke

Black smoke can be an indication of the mower burning too much fuel and not have enough access to air.

In the case of black smoke, the usual culprit is that the fuel is too rich as it doesn’t have access to enough air to mix with. You can fix that by cleaning the air filter if it is dirty, but you may also need to adjust the carburetor.

For more detailed information, make sure to double-check the specific instructions for your lawn mower in the user’s manual that came with it.

What If the Smoke Doesn’t Stop?

As you can see now, the smoke does not necessarily mean something terrible. In either case, the smoke should stop after a few minutes.

However, if it doesn’t, this can mean that you could have more serious problems at hand.

Worn out and damaged seals, blown head gaskets can all be very dangerous.

If the smoke doesn’t seem to stop turn off your lawn mower, look for any damaged parts and if needed, have it serviced by an authorized mechanic.

How to Prevent a Lawn Mower from Exploding?

The most important thing you can do to prevent these accidents is keeping your mower in top condition – this can be done by following all the recommendations in your user’s manual, and performing regular maintenance on it.

Additionally, here are some good practices to follow:

  • Avoid refueling the lawn mower while it is still hot;
  • Don’t cut dense tall grass, nor wet grass;
  • Avoid using the lawn mower for extended periods during the hotter days of summer;
  • Make sure there are no rocks, sticks, branches, toys and any other stationary hazards that the blades of the mower can come in contact with;
  • Make sure to have the blades of the lawn mower sharpened;
  • Make sure to always use a clean air filter;
  • Be sure to check that you are using a proper fuel mix (fuel and oil mixture in case of a 2-stroke engine);
  • Regularly clean and remove the grass clippings from the underside of the mower’s deck and from the engine’s cooling fins;
  • Be careful with tilting your lawn mower to the side while cleaning it or while working on slopes and hills;
  • Do not store your lawn mower in your shed, garage or any other structure before it had enough time to cool off completely;
  • Avoid flooding the engine, and if that happens, don’t force-start it in any way. Leave the mower to the side and give it enough time for the fuel to evaporate on its own.

Additional resources and further reading:


Peter Toth

Hi! I'm Peter, the owner of BackyardGadget. Working around the house has always been a big part of my life. I've created this site to share my experience, and to help people choose the right tools for the job. Thank you for stopping by!

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