Servicing the Spark Plugs
Service Interval: Every 100 hours—Check the spark
plugs.
Make sure 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(s) and a gapping tool/feeler
gauge to check and adjust the air gap. Install a new
spark plug(s) if necessary.
Type: NGK® BPR4ES or equivalent
Air Gap: 0.75 mm (0.030 inch)
Removing the Spark Plugs
1. Disengage the PTO and engage the parking
brake.
2. Shut off the engine, remove the key, and wait
for all moving parts to stop before leaving the
operating position.
3. Remove the spark plugs as shown in
31).
A
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Figure 31
1. Spark-plug wire/spark plug
(Figure
B
Checking the Spark Plugs
Important:
Do not clean the spark plugs. Always
replace the spark plugs when they have: 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).
Installing the Spark Plugs
Tighten the spark plugs to 22 N∙m (16 ft-lb).
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31
Figure 32
Figure 33
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