How to Install a New String on a Homelite Mightylite UT21947 Trimmer

You can install new string on your Homelite Mightylite trimmer in one of two ways. Replace the entire spool with string already wound for you, or rewind new string yourself. The second option may take a little longer but will definitely save you money over the life of your string trimmer. You can purchase replacement string in bulk at home and garden stores in your area. Just buy the right diameter string, otherwise you won't be able to use it.

Things You'll Need

• Rag
• Scissors
• 18 feet of .08-inch replacement string

Instructions

Installing Pre-wound Spool

1. Stop the engine and wait for the cutting head to stop spinning. Unhook the rubber wire that's connected to the end of the spark plug. This will prevent any accidents during string replacement.

2. Hold the string head in one hand while unscrewing the spool retainer counterclockwise. Lift the old spool out of the spool retainer, keeping the spring underneath attached to the spool retainer. Discard the old spool.

3. Hold the replacement spool over the spool retainer. Capture the string ends in the slots on the spool and make sure they extend outward 6 inches. Insert the string ends through both eyelets on the spool retainer.

4. Push the spool down into the head. Grasp the string ends and pull them up to release them from the notches. Push the spool down while turning it counterclockwise until it no longer spins. Rotate the spool clockwise a bit to make sure it's anchored to the head.

Replacing the String

1. Stop the engine and wait for the cutting head to stop spinning. Unhook the rubber wire that's connected to the tip of the spark plug. Grasp the cutting head and screw the spool retainer counterclockwise. Take the spool out of the cutting head. Keep the spring attached to the head.

2. Clear off any old bits of line from the spool. Wipe the spool clean with the rag. Measure out 18 feet of new string. Cut the line in half to get two equal lengths, each 9 feet in length. Thread the first length of string into the anchor hole on the upper part of the spool.

3. Wind the first length around the upper part of the spool counterclockwise. Push the first string into the holding slot on the upper part of the spool. Leave 6 inches of string extended outward. Repeat the same winding process with the second string using the bottom half of the spool.

4. Turn the spool over and thread both string ends into the eyelets on the head. Push the spool down against the spring. Grasp both string ends and pull them up to release them from the holding slots. Push the spool down and turn the spool counterclockwise until it locks into place. Turn the spool clockwise to anchor the spool to the head.

Tips & Warnings

• The spring inside the head is under tension and may cause injury if it pops out unexpectedly.

References

• K & T Parts House: Free Homelite Parts Manuals
• K & T Parts House: Homelite Service Manuals