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How to Replace the Speed Spool on a Troy-Bilt String Trimmer

By Eric Blankenburg ; Updated September 21, 2017

Troy-Bilt string trimmers operate with a moving head that runs at high speeds to slice through the base of weeds. The spool needs to spin fast enough, so if anything is preventing it from acquiring the necessary speeds, you won’t get your trimmer to cut anything. Cracks, holes and other wear can cause the spool to slow down or work improperly. Replace the spool if you notice it slowing down or if it has cracks or other damage.

Shut down your Troy-Bilt trimmer’s engine. Lift up the head attachment. Press in both tabs on the spool and lift up the bottom cover. Slide the bottom cover and inner reel out of the head.

Wipe down the interior of the spool with the rag. Position the pawl on the spool so that it hooks onto the spring. Slide the screwdriver into the access hole on the outer spool and underneath the pawl. Position the end of the screwdriver so it is right next to the pawl shaft.

Turn the screwdriver until the pawl lifts off its retaining hole. Remove the screwdriver and pawl. Remove the spring from the spool. Locate the head’s locking nut and bolt on top of the head where it connects with the shaft. Unscrew the nut and bolt.

Slide the spool off the shaft’s stub. Set the new spool onto the stub. Insert the bolt into the hole and tighten its nut with wrench and screwdriver. Insert the old spring into the new spool. Push down the pawl until it snaps into place on the spool.

Refit the inner reel against the spring. Position the cover over the inner reel. Push the cover down until you hear the tabs click. Test the head to ensure that the cover and inner reel are properly attached.


Things You Will Need

  • Rag
  • Flat-blade screwdriver
  • Wrench

About the Author


Currently based in Minneapolis, Minn., Eric Blankenburg has been a freelance journalist since 2000. His articles have appeared in "Outside Missoula, Outside Bozeman," "Hello Chengdu" and online at GoNomad.com and various other websites. He holds a Bachelor of Arts in creative writing from the University of Montana.