Husqvarna weed trimmers use nylon string, which wears down over time and needs replacement. There is no need to consult a professional for this procedure; however, you must carefully disassemble and properly add your new line to keep the trimmer running at its full potential. When you purchase a weed trimmer, you will receive an owner's manual, which can help with any specifics beyond basic replacement. You can have the trimmer up and running again quickly by following the basic replacement steps.
Disconnect your Husqvarna weed trimmer from any power source to avoid injury. Unplug electric models, or disconnect the spark plug from gas powered models. Spark plugs are generally located prominently on the engine; consult your owner's manual if you have trouble locating the plug on your model.
Turn the weed trimmer so that the line head faces you. Press in on the two tabs on either side of the cover hub to release the hub. Pull the hub straight off of the main body of the tool to expose the line spool.
Lift the spool off of the main weed trimmer head so that you are holding only that piece. Remove any remaining old line from the spool.
Cut two pieces of replacement line, each measuring 10 feet long, with wire cutters. Insert one end of each replacement line into the small notches on the spool; one notch is on the top and the other on the bottom.
Wind the two pieces of line clockwise around the spool, following the arrow on the spool. Make sure you keep each piece of line in its own section. Wind in smooth, even circles to avoid crossing or tangling the line.
Wind until there are about 6 inches remaining on the end of each line. Hook the remaining line into the notches on the edge of the spool to hold the line in place while you reassemble the weed trimmer.
Push the spool back into place; depending on the Husqvarna model, you may need to thread the ends of the string through eyelets to allow it to extend beyond the weed trimmer. Push the spool and hub back into place until they click, indicating that they are secured and ready for use.