Spark plug must be securely tightened. Improperly tightened plug can become
very hot and cause engine damage.
Spark plug must have correct heat range.
Check plug electrode gap with wire feeler gage.
Correct gap as necessary by bending side electrode (1). Electrode gap should be 0.039-0.043 in. (1.0-1.1
Make sure sealing washer (2) is in good condition and, with washer attached, hand-thread spark plug (3) to
Use spark plug wrench to tighten an additional 1/2 turn.
Install plug cap (4).