How Often Should You Replace Your Lawn Mower Air Filter?

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Many people don’t even realize that lawn mowers have air filters in them but they do. These filters need to be changed regularly. Just like the air filter in your vehicle, lawn mowers’ air filters are there to catch dirt and various types of debris so that it doesn’t enter the engine.

If your air filter is old because it hasn’t been changed in a while, certain particles will be able to reach the carburetor and then the engine. This can cause the engine to slow down and maybe even be damaged permanently.

So, how often should you replace your lawn mower air filter?

The air filter on a lawn mower should be changed at least once a season, ideally before the cutting season starts. That being said, the air filter should be cleaned in the meantime. The air filter should be cleaned about every ten times the lawn mower is used.

It isn’t a difficult of a job to do at all. Just keep in mind how important the filter’s job is and you’ll be able to remember how important it is to clean it and replace it on a regular basis.

Why Is It Important to Replace the Air Filter?

If you compare your lawn mower’s air filter to the filter on your vehicle, you’ll understand why it is such an important component.

All of the dirt and debris from the air that surrounds the lawn mower consistently creeps into the mower. Ultimately it would go straight to the motor if there wasn’t some type of filter placed in the way. If you forget about it and the filter gets too dirty, it can essentially clog up the motor to the point where it doesn’t work any longer which can be very costly. 

6 Signs You Need to Replace Your Mower’s Air Filter

Before you go to replace the air filter in the your lawn mower, you’re probably wondering what kind of symptoms a dirty air filter will give you.

Here are some of the first things you may notice…

Rough Starts

The engine will struggle to pull air in if the filter is not working properly. This may result in the mower backfiring.

Reduced Fuel Efficiency

You’ll use more fuel in your lawn mower because the air/fuel mixture is off when the air filter is dirty.

Less Power

Since the engine cannot draw enough air in through the air filter, it may try to compensate by using more fuel which reduces power.

Fouled Spark Plugs

The change in fuel ratio can cause your spark plugs to foul out. You may get a lot of carbon build up on the engine too.


Because of the faulty air filter, oxygen may not be able to reach the engine and so the fuel may not be burning properly. This can result in fuel leakage.

Visible Dirty Filter

Upon checking the air filter you may see a lot of dirt on the filter or it may have frayed fins.

Sometimes it can be a little hard to know whether the air filter just needs to be cleaned or fully replaced. 

As you can see in the photo below, my lawn mower air filter is a little dirty but it doesn’t need to be replaced yet. While there is some debris on it, I should be fine to get by on this filter for a little while longer because most of the dirt is only on the edge of the fins.

A filter that needs to be fully replaced may be stained black and have damaged fins.

You May Not Need to Replace the Air Filter…

Cleaning the air filter is pretty easy! Here is the easiest way to do it:

  • First thing’s first – turn the mower off and make sure everything has stopped.
  • Find where the spark plug wire is located and disconnect it.
  • Remove the cover that sits on top of the air filter.
  • Take the foam filter out and rinse it thoroughly with water, then let it dry completely.
  • If you find a paper filter instead of a foam one, throw it away – never replace it.
  • Insert the new air filter (if this is what you wish to do) and replace the cover.
  • Reconnect the spark plug wires and you’re done!

The process of cleaning your lawn mower’s air filter is not a time-consuming one but it certainly goes a long way in making sure the mower works efficiently all season long.

It also doesn’t cost you anything, so there is no reason not to keep up with this task. If you’re not sure about how many times makes that magical number “ten,” you can simply clean the filter once a month or every six weeks. After all, if you clean the filter more than you need to, it’s never a problem. It only becomes a problem when you aren’t cleaning it enough.

Replacing Your Mower’s Air Filter Correctly

It’s a good idea to replace your lawn mower’s air filter either at the very beginning or the very end of the season, because this is the best way to remember that your filter needs to be changed.

To start, you have to find the covering on your filter which is usually made out of either metal or plastic. This is a protective covering that is important to keep connected unless you’re replacing or cleaning your filter. When you find this covering, go ahead and remove it, then locate the paper or foam filter inside.

If the paper filter looks cloudy when you hold it up to a light source, this means it needs to be changed. If you have a foam filter and not a paper filter, brown or yellow stains means it’s time for a replacement. Go ahead and remove the filter, then take a dry cloth and clean the area around where the filter was located. Never use any type of cleaning products because they could damage that part of your mower.

Once you have replaced your filter, you can go ahead and reattach the cover. Never force the filter into the space and always work gently to get your filter replaced, regardless of the type you have. If you are working to replace your filter and you’re having problems with either the filter or the filter cover, it’s likely that something isn’t aligned correctly. Work slowly and be patient to figure out the problem so that everything is done correctly. This is the best way to ensure nothing breaks or that the filter isn’t replaced improperly.

You also need to keep in mind that operating your lawn mower without an air filter, even for a short period, can cause serious damages to the engine.

Cleaning and/or replacing your air filter regularly is crucial to making sure you keep your lawn mower for a long time. Properly maintaining the mower is certainly less expensive and less time-consuming in the long run.

In Summary – How Often Should You Replace Your Lawn Mower Air Filter?

The air filter is an important component of your lawn mower regardless of the type or size you have. It needs to be replaced once a year and cleaned every 10 or so uses. Neither of these tasks is complicated, expensive or time-consuming and these basic maintenance measures greatly increase the lifespan of your lawn mower. It will help it run more efficiently year after year.

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