How to Check and Clean a Riding Lawn Mower Air Filter

Disconnect the spark plug wire

• Examine the engine until you find the spark plug, then disconnect the wire connected to it. This ensures the engine won’t accidentally start while you’re working.

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Open the filter housing and remove the air filter

• Examine the engine, looking for a removable plastic cover on the top or possibly on either side. This is the air filter housing.
• Remove the air filter housing cover. Most riding lawn mowers are designed for this to be done by hand.
• If your filter housing is held in place with bolts, unthread and carefully place them somewhere nearby so they won’t get lost or fall into the engine.
• With the cover off, gently pull the air filter out from its housing and put it to one side. Depending on the model of the mower you’re working on, the filter might be a paper cartridge style or a simple piece of foam. Cleaning procedures will vary slightly for each.

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Protect the air inlet

• With the air filter free of its housing, stuff a clean, dry shop rag into the inlet port at the back of the housing. This prevents debris from getting into your carburetor during cleaning.
• Be sure to leave enough of the shop rag sticking out of the port that you’ll easily be able to pull it out when you’re done.

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Clean the filter housing

• Use your air compressor and spray nozzle to blast any dirt and debris from the inside of the filter housing. Be sure the shop rag is firmly blocking the inlet port before doing this.

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Determine if the filter needs cleaning or replacement

• Examine your air filter. If it’s the paper cartridge type, look closely at the paper pleats. If they’re only moderately dirty, chances are cleaning the filter will be sufficient. If they’re completely caked in dirt and discolored, you’ll need to replace the filter.
• If your filter is the all-foam variety, it can be cleaned in warm, soapy water if it’s not too dirty. As with the paper cartridge filter, replace your foam filter if it’s completely caked in dirt and debris that won’t come off easily.

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Install a new filter or clean the old one

• If your air filter is beyond saving, throw it out and install a new one of the same type. Check your mower’s manual or do a Google search to find filters compatible with your machine.
• Be sure to remove the shop rag you stuffed in the air inlet before installing the new filter.
• If your filter still looks like it has some life left, tap it gently against the nearest hard surface to knock loose as much dirt as you can. If it’s a foam filter, gently wash it in warm, soapy water, then set it somewhere warm to dry.
• If you’ve got a paper filter, stuff a clean shop rag into the center to keep dirt out, then blow off the outside with the air compressor, getting all surfaces as clean as possible.
• With the outside of your paper filter clean, remove the shop rag, then insert your air spray nozzle inside and blow out the filter from the inside out.
• If your paper cartridge filter has a removable outer wire mesh or foam sleeve, take it off and clean it separately. If you use water, be sure to let the protective cover dry fully before replacing it over the filter.

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Re-install the cleaned filter

• With your filter fully cleaned, remove the shop rag from the air inlet, then carefully re-install the filter.
• Replace the filter housing cover, then reconnect the spark plug wire and you’re done! If it still doesn’t start, then try replacing the fuel filter.

Robert Maxwell for Family Handyman