Part of a complete lawn mower maintenance program is servicing the spark plug. An old spark plug may be dirty, pitted, covered in carbon, or have worn electrodes, resulting in hard starting and poor operation.
The spark plug should be cleaned or replaced after 50 operating hours. The type of spark plug for your mower will be listed in the owner's manual.
- Stop engine and wait for moving parts to stop.
- Disconnect spark plug wire.
- Clean debris around the spark plug housing.
- Remove the spark plug with appropriate deep socket and clean it with a wire brush, removing any carbon buildup.
- Inspect the plug for cracks, damage, or worn electrodes. Replace if necessary.
- Set the gap on the plug to manufacturer's specs. See owner's manual.
- Install the spark plug by hand, then gently tighten it with the socket wrench. Do not over-tighten and break spark plug!
- Reconnect the spark plug wire.
