Honda Power Products WJR2525 Manual De Explicaciones página 63

7. After the spark plug is seated, tighten with the 16×17 mm box
wrench to compress the washer.
NOTE:
When installing a new spark plug, tighten 1/2 turn after the spark
plug seats to compress the washer. When reinstalling a used spark
plug, tighten 1/8–1/4 turn after the spark plug seats to compress the
washer.
8. Attach the spark plug cap.
9. Install the engine top cover, and tighten the 4 mm hex. bolt
securely.
CAUTION:
The spark plug must be securely tightened. An improperly tightened
spark plug can become very hot and may damage the engine.
60
16×17 mm BOX WRENCH