Hi! My name is Matthew Christian from Tampa, Florida and on behalf of Expert Village, today I would like to talk to you about how to use and properly maintain a limb chain saw. Two cycle engines such as this one tend to foul out or wear out the spark plugs rather quickly. It may be necessary from time to time if you are having a hard time getting your machine started or if it is not running like it used to, it is probably a good indicator that it is time to replace the spark plug. To do so we simply take off the cap. We will use the socket wrench to remove the spark plug and make sure to replace with the same like and kind of spark plug. Not all spark plugs are created equally. There are different sizes and different heat ranges of spark plugs. Be sure to use the recommended spark plug per manufacturer. Replace the spark plug, re-install the cap and you should be ready to go.