Honda Outboard Motor BF20 Owner's Manual page 31

Spark Plug Service
Recommended spark plug: BMR-4A (NGK)
1. Remove the engine cover.
2. Remove the spark plug cap.
3,Use the wrench supplied in the tool kit to remove the spark plug.
4.Visually inspect the spark plug. Discard it if the insulator is cracked or
chipped.
5. Measure the plug gap with a feeler gauge.
The gap should be 0.6-0.7 mm (0.024-0.028 in). Correct as
necessary by bending the side electrode.
6. Attach the plug washer. Thread the plug in by hand to prevent cross-
threading.
7. 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.
8. Reinstall the engine cover.
CAUTION:
0 The spark plug must be securely tightened. An improperly tightened plug
can become very hot and possibly damage the engine.
0 Never use a spark plug with an improper heat range.
SOCKET
WRENCH
0.6-0.7
mm
(0.024-0.028
in) t
29