Remove the starter from the Weed Eater lawn mower by loosening the bolts using a wrench. Pull the starter housing away from the engine and turn it over. Remove the old cord from the starter.
Rewind the starter pulley on the spring. Twist the pulley until you feel it begin to tighten up and then back off one full turn. Do not overtighten the pulley or the cord will not rewind properly.
Insert a screwdriver into the opening to hold the pulley still. Insert the new starter cord into the eyelet. Tie a knot into the end of the cord so that it does not pull out of the pulley.
Remove the screwdriver from the hole in the pulley and allow it to retract slowly, winding the starter cord as it retracts. Place the starter housing on the Weed Eater lawn mower. Tighten the retaining bolts using a wrench. Pull the cord several times to make sure it retracts properly.