Pull the spark plug wire with a pair of needle-nose pliers.
Pull the pull string out about three inches if you can and cut it just below the rubber T-shaped pull-handle. If the String is completely recoiled inside your weed eater, you may have to use an Exacto knife or a box cutter to cut the string between the bottom of the handle and the weed eater.
Remove the screws holding the weed eater's outer shield in place. Depending on your Stihl's model, there may be anywhere between four to six screws. Remove these screws with a screwdriver and pull the shield free from the rest of the weed eater.
Use a screwdriver to unwind the string from the recoil spool. This is the wheel-like assembly that holds the weed eater string.
Remove the nut in the center of the recoil spool starter assembly. Pry the recoil starter mechanism up and out with a screwdriver.