4. Visually inspect the spark plug electrodes
for wear. The center electrode should have
square edges and the side electrode
should not be eroded.
5. Discard the spark plug if there is apparent
wear or if the insulator is cracked or
chipped.
6. Check the spark plug gap (4) using a
wire-type feeler gauge. If adjustment is
necessar y, bend the side electrode (5)
carefully.
The gap should be:
0.8 – 0.9 mm (0.03 – 0.04 in)
(5)
(4) Spark plug gap
(5) Side electrode
(4)
(6)
(6) Center electrode
7. Make sure the plug washer is in good
condition.
8. With the plug washer attached, thread the
spark plug in by hand to prevent cross-
threading.
9. Tighten a new spark plug 1/2 turn with a
spark plug wrench to compress the
washer. If you are reusing a plug, it
should only take 1/8 – 1/4 turn after the
plug seats.
NOTICE
The spark plug must be securely tightened.
An improperly tightened plug can become
very hot and possibly damage the engine.
10. Reinstall the spark plug cap.
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