How to Change a Filament in a Stihl Weed Eater

STIHL manufactures many types of trimmer heads, and the procedure for restringing almost all of them is similar. The exception is the Autocut Easy Spool model, which is simpler to restring. When you're restringing your STIHL weed eater, it's essential to use string of the correct diameter for your model, or the trimmer won't work properly. You can find out which string to use by consulting the instruction card that came with the trimmer or consulting the STIHL website. You don't have to limit yourself to round string. STIHL manufactures string with various angled cross sections for more efficient cutting.


Turn off the machine and unplug it, or pull the wire off the spark plug. If you have a battery-powered model, remove the battery.


Turn the trimmer over and examine the head. You may have an Autocut, Trimcut or Autocut Easy Spool model. Replacing the string on the first two models requires removal of the spool.


Remove the spool from an Autocut head by grasping the bottom of the head with one hand and depressing the tab in the side of the head with your finger. Turn the head 180 degrees, depress the other tab, pull off the cover and lift out the spool. To remove the spool from a Trimcut head, unscrew the locknut on the top of the head to remove the cap. Once the cap is off, you can lift off the spool.


Cut two equal lengths of string from a spool with wire cutters, being sure you're using the proper string for your model. Consult the trimmer instructions for the lengths of string you need. This instruction also applies if you're restringing an Autocut Easy Spool head.


Feed an end of one of the strings into one of the holes in the hub to anchor it. Wind the string tightly around one half of the hub, which is divided into two sections, following the arrow imprinted on the spool. When about 5 inches are left, hook the line to one of the notches in the rim of the spool.


Wind the second string in the same direction on the other half of the spool. Be sure to feed it into the hole on the opposite side of the spool from the one you used for the first string. Hook it into the notch on the opposite side of the rim.


Replace the spool in the head if you have an Autcut model. Line up the notches on the rim with those on the head, push the spool down and give it a little twist to lock it. Feed the strings through the notches on the head and replace the cap, pushing down sharply on it until it locks. Pull the strings sharply to engage the spool.


Set the spool into the head, if you have an Autotrim model, and feed the ends through the holes in the cap. Pull them tight as you place the cap on the head and push down to lock it. Pull on the stings to engage the spool.


Restring an Autocut Easy Spool head by turning the spool head until the arrows line up with those on the spool housing. Feed the end of one string into one of the holes on the side of the head and push it in as far as it will go. Feed the other string into the hole on the opposite side of the head in the same way. Turn the spool in the direction of the arrows imprinted on it to automatically wind the string.

Things You Will Need

  • Wire cutters


  • Clean the trimmer head when you remove the cap and spool. Even though you don't need to remove the cap to wind an Autocut Easy Spool head, it's a good idea to do it periodically to clean it.

About the Author

Chris Deziel


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