Honda WH15X Owner's Manual page 28

4. Measure the plug gap with a feeler gauge.
Correct as necessary by bending the side electrode.
The gap should be:
0.70 0.80 mm (0.028 0.031 in)
SIDE ELECTRODE
SEALING WASHER
5. Check that the sealing washer is in good condition, and thread the
spark plug in by hand to prevent cross-threading.
6. After the spark plug is seated, tighten with a spark plug wrench to
compress the washer.
If installing a new spark plug, tighten 1/2 turn after the spark plug seats
to compress the washer. If reinstalling a used spark plug, tighten 1/8
1/4 turn after the spark plug seats to compress the washer.
The spark plug must be securely tightened. An improperly
tightened spark plug can become very hot and may cause engine
damage.
Use only the recommended spark plug or equivalent. Spark plugs
which have an improper heat range may cause engine damage.
7. Attach the spark plug cap securely.
0.70 0.80 mm
(0.028 0.031 in)
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