Air filters come in different shapes and sizes and play an essential role in helping the engine carry out the very calculated combustion process. But, as you’ll soon find out, a dirty air filter will cause your lawn mower to struggle in many ways and turn what should be an enjoyable few hours in the yard into a long, painful nightmare. So, instead of waiting for problems to happen, I suggest adding air filter cleaning as part of your lawn mower maintenance routine. Let me explain a little more about the role of air filters and how you can give yours a good cleaning.
Why is Cleaning an Air Filter Important?
Scientists figured out that the air-fuel ratio (AFR) required to properly run an engine should be in the region of 14.7:1. They also discovered that this very precise ratio can be preserved with the help of an air filter designed with certain filtration specifications.
What it boils down to is that a mildly dirty filter is going to dramatically mess up the air-fuel mixture and create several problems.
Ok, so what problems should you look out for?
- Mower Won’t Start
- Decreased Performance
- Decreased Fuel Economy
- Lawn Mower Blowing Back Smoke
- Mower Backfiring
- Problems with mower overheating
How to Clean Your Lawn Mower Air Filter (Paper or Foam)
Before you reach for a new air filter, try cleaning your existing one. If done correctly, you can get some significant extra life out of your filter and save a few dollars.
Some lawn mowers have just one filter, while others have a main filter plus a pre-filter. Because different filters require different cleaning methods, you’ll need to know what material your filters are made of before getting started.
How to Clean a Lawn Mower Paper Air Filter
Paper filters tend to be more delicate and can easily damage if not cleaned gently. Paper filters are made of compressed fibers that form a web to catch particles from the air. Cleaning a paper filter will cause the web to become over-compressed and less effective in catching dirt.
Additionally, compressed fibers increase differential pressure in the filter, causing the paper to tear and pull apart. All of this means that you must be very careful to avoid causing problems if your filter is made of paper. More often than not, paper filters should be replaced when dirty.
But sometimes it is possible to extend their lifespan, so let’s take a look at how to clean a lawn mower’s paper air filter.
Tools Required to Clean a Paper Air Filter
- Compressor Air Gun
Tap Out the Air Filter
With the dirty filter in hand, give it several gentle taps on a hard surface. Be cautious not to cause any damage to the filter.
Blow Out the Air Filter
Using your air gun, gently blow from the reverse side of the filter, followed by blowing across the front side to remove loose dirt. Try not to blow directly into the face of the filter, as this will push dirt deeper into the filter.
Inspect the Air filter
Once you have cleaned the filter, inspect it for damage. If you find any holes or tears, then it’s best to throw the filter out and replace it with a new one. On the other hand, if everything looks good, your cleaned air filter is ready to be reinstalled on the lawn mower.
How to Clean a Foam Air Filter on Lawn Mower
Foam filters are much more robust and can handle a good cleaning. They’re usually used as a pre-filter to catch the bulk of the bigger material before it reaches the main filter. Let’s go over how you can clean the foam air filter on your lawn mower.
Tools Required to Clean a Foam Air Filter
- Compressor Air Gun
- Filter Cleaner Spray (Spray Degreaser)
- Clean Water
- Filter Oil Spray
- Paper Towel
- Ziplock Bag
Blow Off the Dirt
Use your air gun to blow off any debris on the filter. Try to get it as free of dirt as possible.
Spray the Cleaner
Using your spray filter cleaner, liberally cover the filter and allow it to soak in for 10-15 minutes.
Rinse Off the Cleaner
Next, rinse the filter under running water, removing all the cleaner and dirt. If you feel that it could do with an additional clean, then reapply the cleaner and repeat the rinse.
Allow the Filter to Dry
Try squeezing out as much water as possible without damaging the filter and allow it to dry. I’d recommend at least 24 hours for it to dry completely.
Oil the Filter
Spray all the filter’s surfaces with the filter spray and place it into a ziplock bag. Then squeeze the bag to work the oil into the middle of the filter. Next, set the filter to one side for 5-10 minutes.
Clean Off the Excess Oil
Take a few pieces of paper towel and place them in the bag with the filter. Again, squeeze the bag and let the paper towel soak up the excess oil.
Inspect & Reinstall
Finally, inspect the filter and check for any damage. If the foam filter is your main filter, then it needs to be free of any holes or damage. If it’s a pre-filter, then a few small holes will be ok. However, it’s important to remember that anything that gets through the pre-filter will damage the main filter. If your filter passes inspection, it can be installed back on the lawn mower.
Mistakes You Want to Avoid When Cleaning Air Filters
One of the main mistakes I see with people cleaning filters is mistaking a paper filter for a fabric filter. Fabric filters are usually used in the automotive industry and can be cleaned like a foam filter. Paper filters shouldn’t be cleaned with cleaning fluids unless stated that it’s ok by the manufacturer.
Additionally, cleaning a filter, so it looks clean is different from cleaning a filter so it performs better. Cleaning the outside of the filter to look good at first glance does not achieve anything. If you open up the fins of an apparently clean filter, you’ll more than likely find a bunch of dirt.
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