String trimmers are handy lawn tools that come in both gas and electric powered models. They work by rotating a bottom head rapidly while ejecting a thin, nylon string. The string cuts through grass blades or weeds and is also used to edge flower beds. When the nylon line runs out you must replace it, and with a two-string trimmer this can be confusing. However, by following a few installation tips your trimmer will be working again in no time.
Unplug the trimmer if it's an electric model, or remove the spark plug if it's a gas powered model.
Turn the trimmer upside down so you can see the rotating head. Look for two tabs on the side of the head; push in on them while pulling upward to remove the head. If there is a knob on the bottom of the trimmer, turn it counterclockwise to remove it before pulling off the head.
Look inside the head or inside the trimmer for a round spool. Pull the spool straight up to remove it.
Open a new pack of nylon string and cut to approximately a 25-foot length. Look at the spool and locate one of the holes in the centre. There are two holes on a two-string trimmer.
Insert 1/2 inch of the line into the hole, then look for an arrow printed on the spool. Wind the line around the spool in the direction of the arrow until you reach the end. Stick the end in one of the notches at the edge of the spool to hold it in place.
Cut another 25-foot piece of fresh line and insert 1/2 inch into the other hole in the spool. Wind the line in the same direction as the arrow, as you did before. When you reach the end, locate the second notch and stick the line in to hold it in place.
Insert the spool back into the trimmer and pull each line free of the notches. Insert the lines through the holes or slots in the side of the head so they protrude out of the trimmer's sides. Replace the trimmer cover by snapping it back into place.
Always replace the line with the same size line that was previously used; thicker or thinner lines can damage the trimmer. If you are coordinated, you can wrap both lines around the spool simultaneously.