Operator's Manual

Maintenance
25
Spark Plug
Service Interval/Specification
Check the spark plug(s) after every 200 operating
hours. Make sure 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.
T
ype: NGK BMR-4A, Champion RCJ–8
(or equivalent) Air Gap: 0.025 in. (0.65 mm)
Removing the Spark Plug(s)
1. Disengage the power take off (PTO), set the
parking brake, and turn the ignition key to
“OFF” to stop the engine. Remove the key.
2. Pull the wire(s) off the spark plug(s) (Fig. 22).
Now clean around the spark plug(s) to prevent
dirt from falling into the engine and potentially
causing damage.
3. Remove the spark plug(s) and metal washer.
2
1
m–2576
Figure 22
1. Spark plug wire 2. Spark plug
Checking the Spark Plug
1. Look at the center of the spark plug(s) (Fig. 23).
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.
IMPORTANT: Never clean the spark plug(s).
Always r eplace the spark plug(s) when it has:
a black coating, worn electrodes, an oily film,
or cracks.
2. Check the gap between the center and side
electrodes (Fig. 23). Bend the side electrode
(Fig. 23) if the gap is not correct.
0.025 in.
(0.65 mm)
2
3
1
Figure
23
1. Center electrode insulator
2. Side electrode
3. Air gap (not to scale)
Installing the Spark Plug(s)
1. Install the spark plug(s) and metal washer. Make
sure the air gap is set correctly.
2. Tighten the spark plug(s) to 18 ft-lb (24 N.m).
3. Push the wire(s) onto the spark plug(s) (Fig. 22).