1. Turn off the engine of your Grizzly 600 and allow it to cool down completely.
2. Locate the spark plug wire; it's a thick black wire connecting the engine block and the spark plug.
3. Unplug the spark plug wire by grasping the rubber boot and gently pulling it off the spark plug.
4. Use a 5/8-inch spark plug wrench or a spark plug socket attached to a ratchet to loosen and remove the spark plug from the engine head.
5. Remove the old spark plug and discard it.
6. Check the condition of the spark plug; if the electrode is worn or damaged, you will need to replace the spark plug.
7. Screw the new spark plug into the engine head by hand until it is snug.
8. Tighten the spark plug using a spark plug wrench or socket to 18-22 foot-pounds (24-30 Newton-meters) of torque.
9. Reconnect the spark plug wire to the spark plug.
10. Start your Grizzly 600 and let it run for a few minutes to make sure the spark plug is working properly.
