Plan the perfect garden with our interactive tool →

How to Clean a Lawn Mower Engine

Regular lawn mower service and maintenance will increase the longevity of the mower and prevent costly engine repairs. Create an annual engine and mower cleaning maintenance plan to be performed at the end of the mowing season prior to winterizing the mower. Check the mower engine and fluid compartments periodically through the mowing season to prevent damage due to low fluid levels. Follow the lawn mower manufacturer’s instructions by always using the recommended gasoline and oil types.

Turn off the lawn mower and make sure all moving parts have stopped.

Clean the entire mower deck with a mild car washing soap and water. Rinse completely and let dry. Make sure the mower is cool prior to washing.

Detach the spark plugs to prevent the mower from starting accidentally. Check the plugs for signs of corrosion or wear. Replace corroded plugs instead of attempting to clean corrosion off.

Remove residue from the cooling fins of an air-cooled engine with a wooden stick or dowel. Fill the water reservoir and check the coolant level in a water-cooled engine. Spray a strong jet of water on the radiator cooling fins to clean off residue.

Replace the fuel filter and drain the fuel tank. Open the air filter housing and clean with a solution of mild car washing soap and water. Rinse completely and let dry. Replace the old air filter with a new, clean filter.

Clean the throttle linkages and mower choke and add lubricant. Lubricate all the fittings on the mower deck to prevent rusting and make it easier to remove if required.

Clean the terminals on the battery. Apply lubricant to the battery posts to prevent corrosion.

Change the oil in the mower and replace the filter. Check the engine oil levels during the mowing season and refill if needed.


Purchase lubricant designed for use on lawn mowers. Lubricant is available at home and garden supply stores or a lawn mower dealer.

Clean the lawn mower blade and underneath the deck annually to prevent the buildup of grass and debris. Remove the mower blade and have it sharpened if the cut grass shows signs of torn blades.

Garden Guides