Toro CM-658H-S Operator's Manual page 32

Checking the Spark Plug
Note: Use a gapping tool/feeler gauge to check and adjust
the gap. Install a new spark plug if necessary.
1. Look at the center of the spark plug (Figure 49). If you
see light brown or gray on the insulator, the engine is
operating properly.
Important: Never clean the spark plug. Always
replace the spark plug when it has a black coating,
worn electrodes, an oily film, or cracks.
1 2
Figure 49
1. Side electrode
2. Center electrode
2. Use a gapping tool for spark plugs or a feeler gauge to
measure the gap between the side electrode and center
electrode (Figure 49).
3. If the gap is not within the specified range, do the
following:
A. If the gap is too small, carefully bend the side
electrode away from the center electrode until
the gap between the electrodes is 0.7 to 0.8 mm
(0.028 to 0.031 inch).
B. If the gap is too large, carefully bend the side
electrode toward the center electrode until the
gap between the electrodes is 0.7 to 0.8 mm (0.028
to 0.031 inch).
Installing the Spark Plug
Important: Ensure that the gap between the side and
center electrodes is correct before installing the spark
plug.
1. Thread the spark plug clockwise into the spark-plug
hole by hand.
Note: Avoid cross-threading the spark plug with the
threads of the spark-plug hole.
2. Rotate the spark plug clockwise using a 13/16 inch
(21 mm) spark-plug wrench until the plug and sealing
washer are seated (Figure 48).
3. Tighten the spark plug as follows:
3 4
G019300
3. Insulator
4. 0.7 to 0.8 mm (0.028 to
0.031 inch) gap
•
When installing an in-service spark plug, tighten
the plug an additional 1/8 to 1/4 turn.
•
When installing a new spark plug, tighten the plug
an additional 1/2 turn.
4. Push the spark-plug wire onto the terminal of the spark
plug (Figure 47).
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