Cleaning a Mower Air Filter

It’s summer time and while some soak up the sun by the pool, others are hard at work trying to get the mower to start. After all, it’s like what one of our service managers said, “When the grass is green, there’s always an air filter to be cleaned!” Obviously there may be other reasons why the mower won’t start, but a dirty air filter is definitely one of the more common issues. Although a clogged air filter is not a critical situation, it could lead to dire consequences if it goes neglected.

Air Filters

So first off, you need to know what an air filter is. Simply put, air filters are important because they keep air and other junk particles like grass and dirt out of your engine in order to keep it running smooth. If you let the air filter clog up, you could face problems such as poor performance and fuel efficiency, a decreased engine life, or simple mower that won’t start. And what good is a mower that does not start? There are three types of air filters: paper, foam, and dual.

  • Paper Filters – Paper filters keep debris from entering the combustion chamber by trapping dirt on outside of the filter and allowing only intended air through compressed fibers with microscopic holes. These don’t require cleaning, just lift the cover, and replace the dirty filter with a new one. Typically they only need to be replaced one to two times a year, change them when they start to look dirty.
  • Foam Filters – Foam filters include a cotton fabric that must be oiled with motor oil which traps dirt and debris and cling to the outside. This type of air filter is renewable, just needs to be washed!
  • Dual Filters – A dual filter is just what it sounds like, two in one. First it air and other particles pass through the foam portion as a “pre-cleaner” then the rest passes through the paper element. These combinations filters offer the highest level of filtering by far.


Cleaning an Air Filter

To ensure your mower’s longevity, you want to make sure your filters are clean. Remember, paper filters are disposable, no need to clean them. Foam and dual filters on the other hand, requires a few things.

Foam Filters

  • First things first, make sure the your mower is turned off and engaged in brake. For a push mower, pull off the spark plug wire from the spark plug then unscrew the wing nut that holds on the air filter housing and remove the housing.
  • Next wash the filter with hot water and a liquid soap that works well on grease. Detergent works really well. Then you want to soak the filter into the water and soap mix making sure it is submerged all the way. Squeeze the water out of the filter with a paper towel. Remove as much water as possible, you can repeat the soaking and squeezing as many times as you want to get it as clean as you.
  • Next you have to add new and clean motor oil to the filter. The easiest and cleanest way would be to put the filter in a plastic bag and add the oil to the bag. You want to make sure you have the right amount of oil. Too much oil can harm the exhaust, causing it to emit black smoke and too little will allow particles to enter your engine. If you have too much oil you can just use the bag to squeeze out some oil or use a paper towel to wrap the filter and then squeeze it out.
  • Clean any debris from the rubber gasket that seals the air filter to the carburetor. If the gasket has tears or pieces missing so that it cannot create a tight seal, replace the gasket
  • Finally just put the filter back in place and you’re all set

Dual Filters

  • Separate the foam filter from the paper cartridge. Gently tap the paper filter on a hard surface to make the buildup fall off. You do not need to use an air compressor otherwise you risk damaging it, if the paper filter is torn you must replace it.
  • Check the manual to see if the foam filter needs to be washed and oiled. If so, repeat the steps you would do for a foam filter stated above.
  • Use a paper towel to simply wipe clean the area where the air filter sits but be careful to not push dirt into the carburetor.
  • Screw the filter back onto the housing. Make sure there are not gaps between the gasket and the housing to avoid dirt filtering in. Then you’re all done!


So hopefully after reading this post you’ve learned one thing….DON’T NEGLECT THE AIR FILTERS! Making sure you replace them when needed and keeping them clean will be better for your mower in the long run. You can even save yourself a headache and a few hundred dollars. In the case that you do have a problem with your mower, don’t hesitate to reach out to us. Howard’s Brothers does Power Equipment Service Repair at all of our locations, we are always happy to help.

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