Honda F501 Owner's Manual page 25

2. Visually inspect the spark plug. Discard it if the insulator is cracked or
chipped. Clean the spark plug with a wire brush if it is to be reused.
3. Measure the plug gap with a feeler gauge. The gap should be 0.7-0.8
mm (0.028-0.031 in). Correct as necessary by bending the side
electrode.
I
0.7-0.8
mm
(0.028~0.031
in)
4. Attach the plug washer. Thread the plug in by hand to prevent cross-
threading.
5. Tighten a new spark plug l/2 turn with the wrench to compress the
washer. If you are reusing a plug, it should only take l/8- l/4 turn after
the plug seats.
IMPORTANT NOTICE
1 The spark plug must be securely tightened. An im-
properly tightened plug can become very hot and possibly damage the
engine. Never use a spark plug with an improper heat range.
24