Servicing the Spark Plug
Ensure that the air gap between the center and side electrodes is correct before installing
the spark plug. Use a spark plug wrench for removing and installing the spark plug and a
gapping tool or feeler gauge to check and adjust the air gap. Install a new spark plug if
necessary.
Type: NGK® BPR4ES
Air gap: 0.76 mm (0.03 inch)
Removing the Spark Plug
1. Park the machine on a level surface, disengage the blade-control switch, and move the
motion-control levers outward to the P
2. Shut off the engine, remove the key, and wait for all moving parts to stop before leaving
the operating position.
3. Clean the area around the base of the plug to keep dirt and debris out of the engine.
4. Remove the spark plug.
Checking the Spark Plug
Do not clean the spark plug(s). Always replace the spark plug(s) when it has a black
coating, worn electrodes, an oily film, or cracks.
If you see light brown or gray on the insulator, the engine is operating properly. A black
coating on the insulator usually means the air cleaner is dirty.
Set the gap to 0.75 mm (0.03 inch).
Maintenance: Engine Maintenance
position.
ARK
G437139
IMPORTANT
G437150
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