Can You Run A Lawn Mower Without An Air Filter?

The gas lawn mower comes with an air filter. Some air filters are made of paper, while others are made of foam. Irrespective of the air filter, all work with the same motive: to allow air movement while stopping dust and dirt from entering the engine. But what will happen if we run the lawn mower without an air filter?

Generally, you can run a lawn mower without an air filter but only for a short period when you don’t have a fresh filter handy. Running the lawn mower without the air filter for longer should be avoided as the engine will suck in the dirt, debris, and harmful substances and get choked. 

This article will discuss why we shouldn’t run a lawnmower without an air filter and how to clean or replace the air filter. So, let’s start reading. 

Lawn mower 1

What will happen if I run my lawn mower without an air filter?

The lawn mower will likely start and work if you run it without an air filter. 

But over time, the lawn mower’s engine will get stuck with small particles and get damaged. 

Below I have discussed some common issues that your lawn mower will get if it runs without an air filter for too long.

1. Reduced life of lawn mower’s engine

If you run your lawn mower without an air filter, external particles will enter the engine and destroy its components.

Inside the lawn mower engine, a moving piston rotates in a closed cylinder. 

If the dirt, debris, or any harmful external particles comes in contact with the piston, there will be continuous wear and tear on the lawn mower engine, leading to its complete failure.

2. Lack of power from the lawn mower

The lawnmowers usually have small engines, so they don’t generate much power.

Without air filters, the engine will suck more air and have less fuel. 

As a result, the engine will run inefficiently due to a lack of power generation. The engine can also misfire and run very slowly.

3. The lawn mower will start slowly

In a lawn mower, it is necessary to have a proper ratio of air and fuel to achieve combustion.

Without air filters, the air will quickly enter the lawn mower engine and will cause difficulties in starting the lawn mower. 

Even if the engine starts, it will keep getting obstructed and can shut down after some time. 

After studying the different reasons, we can clearly understand there is no benefit to running a lawn mower without an air filter.

Air filters are cheaper and easy to install, so it’s always better to run the lawn mower with air filters.

How can I install or replace an air filter in a lawn mower?

Installing an air filter in a lawn mower is quite easy; sometimes, you don’t need any equipment to install it.

Before installing the new air filter, check whether it is appropriate for your lawnmower brand and model. 

The air filter can leak air and dirt particles if it isn’t suitable for the lawn mower. 

You can fix a new air filter in your lawn mower by following the gives steps below.

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1. Detach the spark plug

Lawn mower spark plug

First, you will need to discover the spark plug cable and disconnect it.

It is an important step to prevent any accidental start-up while setting up the new air filter. 

Take off the spark plug from the spark plug cable and ensure that both don’t come in contact with each other.

2. Find out the air filters housing

Search for the air filter housing.

The air filters are usually placed behind plastic or a metal cover in the lawn mower. 

Check the air filter housing on the side of the engine.

It is mostly secured with screws, clips, bolts, or clips, depending on the brand and type of your lawn mower.

3. Open the air filter cover and take the air filter out

Remove the clips and screws to open the air filter cover.

Inside the air filter cover, you will find the air filter and the pre-cleaner made of foam. 

The pre-cleaners are prepared using foam and are long-lasting.

Pre-cleaners are not present in all lawnmowers.

However, if your lawn mower has a pre-cleaner, you must check, clean, and change it when required.

4. Clean out the air filter cover and air filter housing

Lawn mower cleaning

You will need to check whether the newly purchased air filters and pre-cleaners can fit inside the air filter housing.

Clean the air filter housing and cover as it may have dirt and debris over them. 

They are usually made with plastic, so you can easily clean them by rinsing them underwater. 

In the meantime, you can use a soft cloth to clean the inner part of the housing and covers. 

After cleaning, let them dry before putting them back on.

5. Place a new pre-cleaner and a new air filter 

Place the new pre-cleaner inside the air filter cover.

After that, put the new air filter inside the air filter housing.

Ensure that the flat end of the air filter should point inward to the engine, and the pointed end should point outwards to the cover of the air filter housing. 

You will need to ensure that the new air filter is installed right so there are no gaps left for the air to enter the engine without passing the air filter first.

If the air filter is not installed properly, the air will enter the engine and damage it.

6. Seal off the air filter cover

In the last step, tighten the screws of the air filter housing.

After installing the new air filter, you will notice that your lawn mower has increased its performance. 

Make sure that the screws should be fairly tight.

Plastic covers usually get cracks if you put excessive pressure on them while tightening their screws. 

Some models of lawnmowers don’t have a pre-cleaner, so at that time, only the main air filter will get replaced or cleaned.

How should I clean the air filters of my lawn mower?

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It would help if you replaced the paper air filters since cleaning or washing them is impossible.

You can clean some dirt from the paper air filter using pressurized air. 

However, the little spaces in the air filter are difficult to clean. 

Although, the foam air filters can be cleaned and reused several times before it’s get replaced. 

The foam air filters are washable and will not get damaged if cleaned carefully. 

Below I have discussed the steps you can follow to clean the air filters using water.

1. Remove and examine the air filter

First, take out the air filter from the air filter housing and disconnect the spark plug.

Check the air filter after removing it.

Check for any holes or damages that can let dirt and debris enter the engine.

After examining the air filter, you can replace it with a new air filter if you notice any signs of damage and wear.

2. Clean the dirt and debris from the surface of the air filter

Take a cloth and remove the heavy debris and solid waste from the air filter surface.

If you notice greasy or sticky stuff, don’t try to remove them; otherwise, you can break the foam air filter.

3. Wash the air filter

Rinse the foam air filter and let it get soaked in warm water for some time.

Add 2 teaspoons of dishwashing liquid to clean the grease from the air filter. 

The air filter contains oil, so it can easily catch dirt and debris.

Therefore, it’s necessary to clean it. 

Use a dishwashing liquid instead of normal hand soap as it is more powerful and easily removes grease and debris. 

Ensure that the dishwashing liquid reaches all the air filter parts. 

Wash the air filter a few times and reapply the dishwashing liquid. 

Repeat the process until all the dirt, debris, grease, and oil is removed from the air filter.

4. Allow the air filter to dry

After cleaning, wrap the air filter in a cloth or paper towel to absorb the extra water.

Squeeze the air filter so that all the remaining moisture drips.

Ensure that the air filter is kept from any moisture.

If it is still wet, you can keep the air filter under a sunny area to let it dry completely.

5. Make use of filter oil

The washable air filters have some oil that catches dirt and debris from the air and prevents them from entering the engine.

Therefore, putting oil into the air filter before installing it back into the lawnmower is always a nice idea. 

You can buy air filter oil and pour it directly on the air filter or take a plastic bag with air filter oil in it and put the air filter inside the bag and squeeze it. 

Clean the excess oil if you find it dripping from the air filter.

6. Place back the air filter in the housing

Put back the air filter in the air filter housing in the same manner you removed it.

You must clean the air filters frequently if the surrounding area remains dusty.

When should I replace my lawn mower’s air filter?

Lawn mower repair 3

If you have a lawn mower with a paper-based air filter, foam-based air filter, or a mix of the main filter and pre-cleaning foam, you will need to replace it periodically for effective performance.

Many manufacturers say you should replace the air filter after using it for 24 hours.

However, the air filter with pre-cleaning foam can last up to 100 hours. 

Even if you use your lawn mower very less, it’s important to change the air filter every season to avoid any problems.

There is a suggested period for changing the lawn mower air filter, but there are also some signs that will help you know the correct time for changing the air filter. 

When there is excessive fuel usage

The lawn mower will not get sufficient air to run properly if its air filter is dirty and clogged.

Check the air filter once if you find that your lawn mower is using more fuel than required.

When the mower’s engine isn’t running smoothly

Air filter replacement is needed if the engine doesn’t run smoothly.

Lack of enough air in the engine can be the reason for its failure. 

You can notice a change in the engine sound if the air filter is clogged with dirt or debris. 

The lawn mower engine is hard and will not get damaged quickly. 

But if the air filter is completely choked and the air can’t pass through, the engine will fail to work. 

Hence it is essential to check the lawn mower air filter to prevent such issues.

Final words

The air filter is one of the essential parts of a lawn mower engine. It allows the movement of fresh and filtered air to the engine. Without the air filter, the lawn mower will get stuck with dirt and debris in no time, and the engine will get damaged.

If the air filters are dirty, there will be no air supply to the engine, and the engine will run less efficiently. A systematic cleaning, maintenance, and replacement of the air filters will keep the lawn mower running for a long time.

Reference: Lawn Mower Technology, Lawn Mower SafetyLawn MowingLawn CareMowing your lawn.


Hello everyone, My name is Richa and I am here to make you a better gardener by creating an in-depth and helpful resource for all the fellow gardeners out there. If I could help even a few people understand their plants better then I call it a success for my efforts.

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