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How to Change the Spark Plugs on a John Deere Riding Mower

If your trusty John Deere riding mower is suddenly riding rough and just doesn't sound right, it might be the spark plug. These plugs provide the spark in the engine compartment that drives the pistons in the engine that power the mower. An aging spark plug can become covered with gunk and carbon deposits, lowering its efficiently. That's why it's important to change the spark plugs on a John Deere riding mower according to the timetable specified by the manufacturer.

Stop the mower in a level location. Disengage any attachments, such as mower blades or hoppers. Lower the attachments to the ground.

Turn off the engine. Set the parking brake and remove the key.

Turn the fuel shut off valve to the "closed" position if your John Deere riding mower has one.

Open up the mower hood. Look for the battery cables, which run from the square black battery mounted on the side of the engine compartment, back to the engine. Use an adjustable wrench to disconnect the negative (black) battery cable from the battery.

Grasp the boot on the spark plug wire firmly and pull straight off.

Connect a spark plug socket to your socket wrench. Slip the socket over the spark plug and turn counterclockwise to loosen.

Gap the spark plug according to the specifications in your owner's manual. Insert a new spark plug and tighten by turning to the right.

Reconnect the negative battery cable.

Riding Mower Doesn't Have Any Spark

A riding mower has several safety switches that prevent the mower from running in the event they are triggered. Examine your owner’s manual for other safety switch locations and check those as well. Older mowers -- typically those built prior to 2000 -- use points and a condenser to deliver an electrical impulse to the spark plug. Replacing these components may restore a spark. If the flywheel is not moving while you try to start the engine, your key may be sheared or worn, resulting in a loss of spark at the plug.


Always follow the instructions in your owner's manual when changing the spark plugs on a John Deere riding mower.

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