Replace lawnmower spark plugs

Why It Matters

Worn spark plugs cause hard starts, misfires, and reduced engine power. A new plug is a few dollars and improves performance noticeably.

Tools

• Spark plug socket
• Ratchet or wrench
• Spark plug gap tool

Materials

• Replacement spark plug (check manual for correct type)

How to Do It

1. Pull the spark plug wire off the plug tip and set it aside so the engine can't start accidentally.
2. Use a spark plug socket and ratchet to unscrew the old plug, turning counterclockwise.
3. Check your owner's manual for the correct gap specification for your engine.
4. Use a gap tool to set the new plug's electrode gap to that specification, bending the side electrode gently if needed.
5. Thread the new plug in by hand first to avoid cross-threading, then tighten with the socket until snug.
6. Reconnect the plug wire until it clicks or seats firmly on the plug tip.

Related Tasks

• Add fuel stabilizer and run mower for 5 minutes Once a year
• Change lawnmower oil Once a year
• Clean and remove grass clippings from mower Once a year
• Reinstall lawnmower battery Once a year
• Remove and store lawnmower battery indoors Once a year