Trimmer mowers clear vegetation without the fatigue of using a trimmer.

How to String a DR Trimmer Mower

by Mary Lougee

DR Trimmer mowers are electric start heavy-duty trimmers with some models available in a self-propelled version for easy cutting of brush, vines and grass. They have two rear wheels and a mower ball on the front that glides along the ground. Two cutting cords rotate on the mower ball to slice through vegetation. Proper installation of new cords is necessary when the cords break or fray and no longer make clean cuts.

Release the bail bar from the handlebar to stop the trimmer head from spinning. Push the throttle control backward to the “Stop” position to stop the engine. Allow the trimmer to cool completely for at least five minutes before replacing the string. Pull the spark plug cap wire off the spark plug to prevent accidental starts.

Turn the trimmer ball with your hand so the old cord is facing the front of the trimmer.

Insert needle nose pliers under the horizontal line of old cord on the trimmer ball. Grasp the cord and wiggle it side to side while pulling outward to remove the old cord.

Measure a 23-inch length of cutting cord in a bulk roll with a tape measure and cut it with wire cutters.

Insert one end of the cord into the round hole on the left side of the plate until it protrudes out the middle, horizontal slot. Insert the other end of the cord in the right side hole of the plate in the same manner until it protrudes out the middle plate next to the first end. The two ends of the cord are in the center of the plate and the excess cord forms a loop.

Pull the two ends outward at the same length. Push the loop upward into the next horizontal plate above the ends. Hold the loop in the groove with one hand and pull both ends outward tightly to lock the cord in position.

Turn the trimmer head 180 degrees in either direction to reveal the second old trimmer cord. Replace the second cord on the opposite side of the trimmer head in the same manner.

Press the spark plug cap onto the spark plug firmly.

Start the trimmer engine, squeeze the bail bar to the handlebar and allow the trimmer head to rotate a few minutes before returning to cutting. This process tightens the cords in the trimmer head.

Items you will need

  • Needle nose pliers
  • Tape measure
  • DR Trimmer cord (bulk roll)
  • Wire cutters


  • Pre-cut cords are available at hardware and home improvement centers.
  • Replace one cord at a time to use the old cord position for the new one.
  • The cutting height is determined by the horizontal plate height on the trimmer ball. The bottom plate is 1 1/2-inches and each additional plate upward is 1/2-inch taller.
  • Install blue, 175-mil cords for cutting heavy brush and green, 155-mil cords for trimming grasses.
  • Store bulk rolls of cord in a plastic bag with a damp cloth to keep the cord pliable.


  • Wear protective eyewear, long pants, a long-sleeved shirt and closed-toe shoes for protection from flying debris when operating a power trimmer.
  • Keep children and pets out of your work area to avoid injuries.
  • Place cords in the bottom four plates on the Sprint and Pro models of DR Trimmers. These two models have a parallel trimming action that allows the head to pivot for fence lines.

About the Author

Mary Lougee has been writing for over 10 years. She holds a Bachelor's Degree with a major in Management and a double minor in accounting and computer science. She loves writing about careers for busy families as well as family oriented planning, meals and activities for all ages.

Photo Credits

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