Weed eaters are lawn maintenance tools that allow you to edge around walkways, trees and other large obstacles where a normal push or riding lawnmower will not allow you to go. Weed eaters are usually simple two-stroke engines that work on a mixture of fuel and oil in one tank. The fuel combusts in the carburetor, which controls the moving head that turns a blade or string to cut grass. To effectively fix a weed eater, you must troubleshoot all components.
Put on your safety glasses and open up the fuel tank to check if there is enough gas in the engine for it to start. Inspect the top of the fuel for any signs of water. Change old fuel if it has been in the tank for more than a month.
Remove the spark plug from the unit using a socket wrench, and inspect the gap of the spark plug using a gap checker tool, available from most hardware stores. Compare the gap measurement to the required gap in the weed eater instruction manual. Tap the end of the spark plug against a hard surface to adjust the gap.
Touch the end of the spark plug to a metal surface if the gap is OK to check the spark. It should be blue. Change the spark plug if the spark is yellow or brownish.
Remove the cover for the air filter by unscrewing the panel using a screwdriver or by loosening the wing nut, and inspect the air filter for excess dirt. Replace the filter if necessary.
Adjust the carburetor if the machine cuts out when at full power. Turn the mower on and adjust the idler screw, turning left, until it feels choppy. Turn the screw for the idler slowly right until it runs smoothly. Do this for all the screws.