Outboard Motor Owner's Manual

5. Spark Plug Service
Recommended spark plug: BMR-4A INGK)
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 0.7-0.8 mm (0.028-0.031 in). Correct as
necessary by bending the side electrode.
6. Check that the spark plug washer is in good condition, and thread the
spark plug in by hand to prevent cross-threading.
7. After the spark plug is seated, tighten with socket wrench to compress
the washer.
NOTE: If installing a new spark plug, tighten l/2 turn after the spark plug
seats to compress the washer. If reinstalling a used spark plug, tighten
l/8- l/4 turn after the spark plug seats to compress the washer.
8. Reinstall the engine cover.
CAUTION:
l The spark plug must be securely tightened. An improperly tightened
plug can become very hot and may cause engine damage.
l Use only the recommended spark plug or equivalent. Spark plugs which
have an improper heat range may cause engine damage.
4
PLUG GAP
0.7-0.8 mm
t
(0.028-0.031 in)
SOCKET
WRENCH
30