The starter rope on a string trimmer is a thin piece of nylon wrapped around a pulley and connected to a recoil spring. This rope can easily get jammed in the pulley, ripped off the spring or break from pulling on it too hard. These starter ropes are crucial in getting combustion to start your engine. If it is not working properly, you will have trouble starting the trimmer.
Find the starter cover. On most string trimmers, this will be in the rear of the engine, near the muffler and gas tank. On other trimmers, it may be near the point where the trimmer shaft connects to the engine. If this is the case, remove the engine from the shaft first.
Remove the starter cover screws. Remove the starter cover from the engine. The starter rope, pulley and recoil spring attach to this cover.
Pull out the starter rope from the pulley. Locate the pulley's locking tab. On most trimmers, this tab will be in the centre of the pulley.
Pop the tab so it is up and open. Pull out the old starter rope from this hole. Pull the rope off the pulley.
Wedge open the rope's plastic handle with the screwdriver. Cut off the knot on the end of the metal insert. Discard the old starter rope.
Thread the new rope through the same hole in the pulley's centre. Pull the rope all the way through and lock the centre tab in place. Tug on the rope to assure firm its attachment to the recoil spring.
Thread the rope through the hole on the starter cover, the plastic handle and the metal insert. Tie a loose overhand knot toward the end of the string and near the metal insert.
Push the rope and the metal insert into the starter handle. Close the starter handle before pulling the knot tight on the insert.
Wind the rope around the pulley. Tug on the cord two full pulley rotations to set tension on the recoil spring. Repeat until there is proper tension on the rope.
Screw the starter cover back in place over the engine.