How to Clean a Lawn Mower Air Filter (Foam and Paper)
In This Guide
The air filter is one of the cheapest parts on your mower and one of the most neglected, yet a clogged one causes hard starting, black smoke, and lost power. Learning how to clean a lawn mower air filter takes five minutes and keeps clean air flowing to the engine. The key is knowing which type you have, because foam and paper filters are cleaned in completely different ways. Below we cover both, how often to do it, and when to replace instead.
Why the Air Filter Matters
The engine needs a steady flow of clean air to mix with fuel and make power. The air filter keeps dust and clippings out of the carburetor and cylinder. When it clogs, the engine is starved of air, runs rich, and loses power, and a badly blocked filter can make the mower hard to start or cause black smoke.
Foam or Paper? Identify Your Filter First
Open the air filter cover, usually a single screw or a couple of clips on the side or top of the engine, and look at what is inside. The cleaning method depends entirely on the type.
| Filter type | How to service it |
|---|---|
| Foam | Wash, dry, and re-oil. Reusable. |
| Paper or pleated | Tap out dust or replace. Never wash. |
| Dual element | Foam pre-cleaner washed, paper element tapped or replaced. |
How to Clean a Foam Air Filter
1. Remove the foam
Take the foam element out of the housing.
2. Wash it
Clean it in warm water with a little dish soap, squeezing gently until the water runs clear. Do not wring it hard enough to tear it.
3. Dry it fully
Squeeze out the water in a clean rag and let the foam dry completely. Fitting a damp filter can bog the engine.
4. Lightly oil it
Work a small amount of clean engine oil through the foam, then squeeze out the excess. The light oil film traps fine dust.
5. Refit
Put the foam back in the housing and close the cover.
How to Clean a Paper Air Filter
Paper filters cannot be washed. To clean one, tap it gently against a hard surface to knock out loose dust, or blow it from the inside out with low pressure air. Hold it up to a light: if you cannot see light through it or it is dark and oily, replace it. Paper filters are inexpensive, so when in doubt, fit a new one.
How Often Should You Clean It?
As a rule, check the air filter every 25 hours of use and clean or replace it at least once a season. If you mow in dusty or sandy conditions, service it more often, since a clogged filter directly costs you power and fuel economy.
A dirty air filter is one of the first things to check when a mower loses power or runs rich, so keeping it clean prevents a surprising number of running complaints.
When to Replace Instead of Clean
Replace a foam filter when it is torn, breaking apart, or so grimy it will not come clean. Replace a paper filter when it is dark, oily, damaged, or you cannot see light through it. Filters are among the cheapest parts on the mower, so replacement is always cheaper than the engine wear a failing filter allows.
If you have cleaned the filter and the mower still runs poorly, the next place to look is the fuel system. A dirty carburetor produces similar symptoms, and Wildwood can clean and service it at your home.
Rather Have a Real Technician Handle It?
A Wildwood technician comes to your driveway, diagnoses the problem, and fixes it on the spot, usually in about an hour. More than 10,000 repairs completed since 2019, with flat rates quoted before we arrive so there are no surprises.