How to Change the String in an Automatic Feed Black & Decker Grass Hog

Unplug the Black & Decker Grass Hog trimmer from the extension cord. Allow the trimmer head to completely stop rotating before attempting to change the line. Place the trimmer upside down on a flat surface so that the trimmer head is facing up.

Press the two tabs on the side of the trimmer line cartridge with your fingers. The tabs are between the two holes where the line feeds through the housing. Lift up on the cartridge while pressing in the tabs and remove the cartridge from the housing.

Turn the cartridge over so that the line spool is facing up. Lift the line spool out of the cartridge. Look at the lever in the bottom of the cartridge. It should remain flat and the teeth should be inside the center teeth, much like the teeth of two gears. Adjust the lever as necessary so that it is flat in the housing if it becomes dislodged when removing the line spool.

Remove any remaining line from the spool and discard the line. Hold the spool in one hand with the slot cut-outs facing up. There are two channels for the cutting line on the spool. Each channel has an anchor hole in the side.

Insert the end of one line from the replacement line kit into the anchoring hole on the upper channel. Wind the line around the spool in the direction of the arrow on the spool. Maintain tension on the line as you wind, and wind the line evenly in layers.

Continue winding until the line reaches the recess cut-out on the top of the spool. Cut the line with a pair of scissors or utility knife. Weave the end of the line into the nearest slots on the spool. Repeat the winding process on the lower channel with the next piece of line. There is a recessed cut-out on the bottom of the spool to determine when to cut the line and slide the opposite end into the slots opposite the first line.

Place the spool into the cartridge with the line ends pointing away from the cartridge. Rotate the spool as necessary until it sits flat in the cartridge. Unhook one of the line ends from the spool holding slot and insert the end through one of the eyelets on the housing. Repeat for the opposite line.

Line up the tabs on the cartridge with the slots on the housing. Press the cartridge into the housing until the tabs lock into place.