How to Troubleshoot 2-Stroke Trimmers

Make sure the trimmer has enough freshly mixed two-cycle fuel in its tank. Push the ignition switch firmly into the "On" position.

Take off the rubber boot on the spark plug, unscrewing and removing the plug with the socket wrench and spark plug socket. Insert the new spark plug and tighten it into the cylinder.

Connect the ignition tester to the end of the spark plug and to the rubber boot. Pull on the starter rope firmly three to four times and look for a blue spark. Take the trimmer to a professional to service the ignition system if no blue spark appears.

Unscrew the fuel cap and drain any old fuel. Take out the fuel filter with the metal hook. Pull it off the end of the fuel hose with your fingers. Clean the inside of the tank and the cap with the brush and rag. Service the tank if the cap, threads, tank or fuel lines look old and degraded.

Close the choke lever. Unscrew the spark plug again. Pull on the starter rope several times to purge the combustion chamber. Connect the compression gauge to the cylinder hole and pull on the rope again. Read the gauge and service the compression and air systems if the reading drops rapidly after filling up.