Turn off the trimmer and disconnect the spark plug wire or remove the battery
Remove the trimmer head cover by pressing the tabs or unscrewing the cap
Take out any remaining old line
Cut the new trimmer line to the correct length for your model
Fold the line in half if using a dual-line head
Insert the line into the spool or align it with the head’s feed holes
Wind the line evenly and tightly in the direction shown on the spool
Leave equal line lengths on both sides if required
Thread the line ends through the exit eyelets
Reinstall the spool into the head
Snap or screw the cover back on securely
Pull each line end to confirm it feeds freely
Reconnect the spark plug wire or reinstall the battery
Test the trimmer at low speed and trim excess line if needed