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How to Change Spark Plugs on a Lawn Mower

    How to Change Spark Plugs on a Lawn Mower

    Spark plugs are integral to a lawn mower’s engine, providing the power needed to cut grass. Unfortunately, these small removable parts may become worn out over time and must be maintained regularly by cleaning or replacement as part of routine maintenance.

    Before attempting to remove your spark plug, always consult the owner’s manual or use a spark plug gap tool to confirm its size for your engine.

    Remove the Cover

    If your lawn mower engine is giving you trouble, it could be time for new spark plugs. Old or dirty plugs won’t create the electrical spark required to ignite gas and power the engine properly – leading to overheating or poor performance of your machine. Therefore, according to manufacturer recommendations in your owner’s manual, they must be changed regularly.

    On walk-behind and riding mowers, the spark plug(s) are usually located on the front side of the engine. To access them, find them and disconnect their spark plug wire by grasping their boot (traditionally made out of rubber or plastic), pulling off straight away from their tip on the spark plug.

    Use a spark plug socket wrench to remove and examine the spark plug for any signs of damage or carbon buildup, then clean it using either wire brushing or solvent as necessary. Also, set your gap tool correctly according to your owner’s manual when replacing it with new spark plugs.

    Disconnect the Ignition Cable

    Spark plug replacement is one of the key elements of lawn mower maintenance, helping ensure that the engine has an appropriate mixture of air and fuel for combustion that produces power to cut grass effectively.

    Before beginning any work on the mower, ensure the engine and covers are cool enough for handling. Next, disconnect the ignition cable from the spark plug; this wire connects it directly to the ignition distributor and supplies electricity – so its removal should always precede any major work on it.

    Carefully thread the new plug into its new location, tighten it with a spark plug socket wrench, and be careful not to cross-thread or overtighten it, as doing so could damage components of your engine, such as wire boots or bootstraps. Finally, reconnect the ignition cable by pushing it firmly until it clicks in place again – your lawn mower is now ready to be enjoyed!

    Remove the Spark Plug

    Switching out your spark plug is a straightforward task that doesn’t require special tools. While most mowers use magnetos for spark, newer models may use electronic ignition instead. Remove the spark plug wire and ratchet the spark plug counterclockwise until loose. Use a socket wrench to avoid damaging ceramic insulation insulators; however, you may reuse spark plugs over time. Changing them at least annually is the best practice to maximize engine performance.

    Start by placing the lawn mower on a stable surface like a garage floor or porch to ensure safety and access to its engine. Disconnecting its spark plug wire, you should manually locate and unthread its old spark plug from its place on the back of the mower engine before using a spark plug gap tool to check that its new counterpart has an appropriate gap (refer to owner’s manual for details). Thread the new spark plug into place by hand, tightening it until finger-tight.

    Install the New Spark Plug

    Replacing your lawn mower spark plug is a straightforward DIY project most homeowners should be capable of handling themselves. Regular replacement should keep your mower operating at peak performance for years and ensure the task goes as smoothly as possible. To make things easy, be sure to have the appropriate tools, such as a regular socket, spark plug wrench, and gap gauge (to check whether the new plug has the right gap size).

    Spark plugs are small removable parts that use electricity to generate sparks that ignite fuel-air mixture, sparking combustion that drives gas-powered engines. Spark plugs don’t last forever and may need cleaning or replacement to maximize engine performance. Follow this step-by-step guide for easy DIY lawn mower spark plug replacement on a flat surface such as a garage floor or porch for safety; writing down your engine’s make and model details before beginning will help identify suitable replacement options at local auto parts stores.


    In summary, changing spark plugs on a lawn mower is a straightforward task that significantly improves engine performance. Regular maintenance ensures a smooth-running mower for a well-manicured lawn.

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