Here are the steps to replace the spark plug on your Lawn-Boy 17754 3-N-1 Gas Lawn Mower: Safety First: Ensure the mower is turned off and the engine is cool. Disconnect the spark plug wire to prevent accidental starting. Locate the Spark Plug: The spark plug is typically located on the side of the engine. You might need to remove the engine cover to access it. Remove the Old Spark Plug: Use a spark plug socket and wrench to turn the spark plug counterclockwise. Once loose, remove the spark plug by hand. Check the Gap: Before installing the new spark plug, check the gap using a spark plug gap tool. The correct gap for your mower should be specified in the owner’s manual. Install the New Spark Plug: Insert the new spark plug into the engine by hand to avoid cross-threading. Tighten it with the spark plug socket and wrench, but do not overtighten. Reconnect the Spark Plug Wire: Attach the spark plug wire to the new spark plug. Test the Mower: Start the mower to ensure it runs smoothly.