Craftsman 154.58973 Operator's Manual page 13

MAINTAINING THE SPARK PLUG
1. Stop the engine and allow it to cool.
2. Grasp the spark plug boot firmly and pull it from the spark
plug (Fig. 13).
3. Clean around the spark plug. Remove the spark plug from the
cylinder head with a 5/8-inch socket, turning counterclockwise.
WARNING:
Do not sand blast, scrape or clean spark
plug electrodes. Grit in the engine could damage the
cylinder.
4. Inspect the spark plug. If the spark plug is cracked, fouled or
dirty, replace it with replacement part Newstar AM5C, or a
NGK CMR5H, or an equivalent spark plug.
5. Use a feeler gauge to set the air gap at
0.025 - 0.31 in. (0.6 mm - 0.8 mm) (Fig. 14).
6. Install the spark plug in the cylinder head. Tighten the spark
plug with a 5/8-inch socket, turning it clockwise until snug.
NOTE: If using a torque wrench, torque to:
159 in.•lb. (18 N•m). Do not over tighten.
7. Reattach the spark plug boot.
0.025 in. - 0.31 in.
(0.6 mm - 0.8 mm)
13
Spark Plug Boot
Fig. 13
Fig. 14