How to Clean Lawn Mower Air Filter

Have you ever experienced a decrease in the efficiency of your mower? Here is a quick guide as to how to clean a lawn mower’s air filter

cleaning mowers air filter

Most people that have a lawn want to keep that lawn looking as nice as possible as often as possible and that means mowing it regularly. In order to achieve this they have probably thought carefully about which lawn mower to buy and as they also want to expend as little effort as possible mowing their lawn, many would have opted for a power mower. This does not necessarily mean they have the tractor type which they sit on and mow the lawn with ease as most people’s lawns are not large enough to justify that expense but they probably have one which they just need to walk behind, guiding it as required.

Like all machinery though, power lawn mowers can develop problems which, unless remedied, could render the mower little better than useless. There are however only three real causes for the engine of a power mower to give trouble and they are the fuel supply, air supply or the spark plugs. One of the most often occurring problems with powered lawn mowers however is a blocked air filter and as this is relatively easy to clean, need not cause the owner any undue expense or time if they clean the air filter themselves.

Although a blocked filter may not render your mower unusable immediately, it will impair its efficiency and can eventually lead to more serious damage to the engine itself. There are tell-tale signs that you can notice if your air filter is becoming blocked and those are:

Power loss – this may be most noticeable in long or wet grass

Fuel Consumption – If the air filter is blocked it will result in more fuel having to be used to mow your lawn

Rough Engine Running – if a mower’s engine starts to cough and splutter, it is probably due to it getting too little air which of course means the air filter is not letting enough air through

Engine Will Not Start – although this may only occur with a badly blocked air filter, a blocked filter can prevent the engine from starting whether it is the pull rope type or a key start

You Will Need:

The air filter will be located at the top of the engine and although you will need a screwdriver in order to access it by removing the protective shroud unless replacement parts are required, that is the only tool you will need for both inspection and fixing.


The inspection will determine if replacement parts such as a new pre-filter or new air filter are needed. Most mowers will have a pre-filter as well as an actual air filter. The pre-filter will usually be foam whilst the air filter will be either foam or paper.

Some mowers do not have a pre-filter but if yours does then inspect it, to see if the foam has become brittle, stiff or stained significantly if so it should be replaced.

The air filer may be paper or foam but if it is foam, once again if it has become significantly discolored it will need to be replaced. If the filter is paper, hold the paper up to sunlight and if a significant amount of light cannot penetrate, the filter needs to be changed.

The housing for the filter should also be inspected for cracks or damage and if any it will need to be replaced.

Cleaning the Air Filter

Regardless of whether or not the filter paper needs replacing, the housing should be cleaned but this should only be done with a dry cloth.


Using any kinds of solvent on the filter housing may damage the paper when it is replaced.

Compressed air should not be used to clean the filter either as this can lead to materials being forced into the mower’s carburetor causing more damage.

Once the housing has been cleaned, the filter can then be put back in place and the protective shroud once again screwed on tightly. It the shroud does not easily screw back on, do not force it as it will probably be due to the filter not being inserted properly. Once the filter is inserted properly the shroud should easily be screwed back in place.

Whilst fitting the filter paper into the filter, care should be taken to ensure the paper is not pinched or torn in any way. Some people try to clean filter papers but this is not recommended as all too often more damage is done to the paper than the dirt alone was causing. However, if the paper only seems lightly used, it can be shaken free of debris and placed back in. It is possible to wash the foam in filters with warm water and detergent before being left to dry but again, this is not recommended as smaller particles of dirt may still remain therefore not clearing the air filter completely.

Once the air filter has been replaced or cleaned, it should add years to the life of your mower as it is seldom that other problems are encountered with good quality mowers.


It is of course important to keep your lawn looking nice and so a good lawn mower is essential but you should choose one which is best suited to both you and your type or size of lawn. Today there are many different types of lawn mower available and for every different type there are many different brands and other options. Once you have decided the type of mower you want, if it is gas powered it may be advisable to enquire from the retailer what type of filter it has and whether they have replacement filters available. As the brands and types of mowers are frequently changing and the price of a new filter is relatively cheap, having a spare on hand may save both time and effort later, especially if the retailer no longer stocks your type of mower.

Apart from air filters, the only other problems usually encountered with power lawn mowers are spark plugs which are easily changed or fuel supply which is often only a case of re-purging the fuel line. This means that most repairs to lawn mowers can be carried out by their owners without the need for expensive professional repair men.