Toro 74621 Operator's Manual page 28

1. Spark-plug wire
4. Clean around the spark plug to prevent dirt from
falling into the engine and potentially causing
damage.
5. Remove the spark plug and metal washer.
Checking the Spark Plug
1. Inspect the spark plug (Figure 33).
Note: If you see light brown or gray on the
insulator, the engine is operating properly. A black
coating on the insulator usually means that the air
cleaner is dirty.
1. Center electrode insulator
2. Side electrode
Important: Do not clean the spark plug. Always
replace the spark plug when it has a black
coating, worn electrodes, an oily film, or cracks.
2. Check the gap between the center and side electrodes
(Figure 33). Bend the side electrode if the gap is not
correct.
Installing the Spark Plug
1. Install the spark plug and metal washer.
1
G017865
Figure 32
Figure 33
3. Air gap (not to scale)
Note: Ensure that the air gap is set correctly.
2. Tighten the spark plug to 15 ft-lb (20 N-m).
3. Connect the wire to the spark plug.
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