Replacing Line in the Line Trimmer Head (sounds complicated but once you have done once very easy). The spool can handle up to .095 line but the recommended size is .080. If you will use line thicker than .080 the black strip at the base of the guard should be removed and the line clipped with scissors to get the desired length.
1) Press on the latch on the side of spool to release one side of cap.
2) One you have released one side, release the other in the same way.
3) Once the cover is off, pull out the black cartridge but don't lose the big spring or the metal washers that go at either end of the spring. The washers may stay in the right spots but they may pop off as well as they are just held there by friction.
4) Cut a new length of line and find approx half way point. Fold line here and hook the fold over the slot in the spool cartridge divider. Wrap both pieces of the line in the same direction (clockwise looking at the black cartridge with the side that has the 2 notches facing up), keeping each line separated by the divider. Clip each line end in one of the 2 small notches on the cartridge to temporarily hold it. Make sure to leave at least 6 inches of line after the notch.
5) Put the spool case on the table with the side attached to the machine (side with screw hole) facing down. Put a metal washer in the middle if it is already not there, and then put the spring in. Take the cartridge and put your thumb and fingers over the notches to stop the line ends from coming loose and then put each ends of the line through one of the holes in the spool case. Push the cartridge and spool case together while pulling the line ends through the holes to pull up the slack. Make sure the spring ends are in the right place. Push the cartridge and spool case together and hold while you gently pull each line end to make sure that the line is off the temporary holding notches.
6) While still holding spool case and cartridge together, slip the round orange bump button into recess in cartridge (make sure 3 knobs on button line up with recesses in the cartridge). Put the cover over and then snap the cover in place.