Weed Trimmer Engine Repair

Drain the gas/oil mixture. Weed trimmers use two-stroke engines that burn a gasoline/two-cycle oil mixture. Replace any fuel that has been sitting in the trimmer for 30 days or more, as gasoline significantly degrades after a month. Mix the gasoline and two-cycle oil according to the manufacturer's instructions. Next, refill the fuel tank.

Replace the air filter on the weed trimmer. Refer to your owner's manual for size specifications and instructions on how to locate the air filter. Open the air filter compartment --- on some trimmers this will be a latch, while others will be closed with screws or a bolt. Remove the old air filter with a screwdriver or wrench and purchase a compatible filter. Insert the new air filter into its compartment and close it.

Install a new fuel filter. Pull the weed trimmer's old fuel filter off, using a pair of pliers. Consult the operator's manual for filter replacement specifications, or take the old fuel filter to a small-engine repair shop or hardware store. Install the new fuel filter in the fuel line and clamp it in place with pliers.

Replace the spark plug. Remove the spark plug cable. Unfasten the spark plug, using a socket wrench. Buy a new spark plug and fasten it in place with a wrench. Reattach the cable and start the weed trimmer.