How to replace a snowblower spark plug

Disconnect the spark plug wire. Use a deep socket and a ratchet to remove the spark plug from the cylinder.

Check your owner’s manual for the correct gap setting. Insert the gap gauge between the electrodes on the spark plug. The gap gauge should fit snuggly between the electrodes; when you pull it out, you should feel only slight resistance. If the gap is too wide, lightly tap the electrode on a clean, hard surface or use a small hammer. If the gap is too small, use the bender on the gap gauge to widen it. 

Thread the spark plug into the cylinder. Hand-tighten the spark plug until it’s snug and then use the ratchet and deep socket to tighten the spark plug another ¼ to ½ turn. Don’t overtighten, because the steel base of the spark plug can strip the softer aluminum threads on the cylinder head.

Reconnect the spark plug wire.