How do I restring a string trimmer?
Stop the trimmer and take out the battery, or pull the spark plug boot on a gas one. Clear out the old line, cut the length your manual names, thread it through the spool with equal ends, wind it the way the arrows show, and leave about 6 inches out of each eyelet. Use only the line diameter your trimmer specifies.
Free to ask. Local shops send quotes, and you pay only when you book one.
By Kasra Taheri, Founder, LoclisPublished
Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.
Step by step
Read when to stop and call a pro, further down this page, before you start.
Step 2: Read the line size in your manual
Use the diameter your manual names and no other gauge or type of line.[1]
Step 3: Clear out the old line
Take off the spool or, on a bump head, press the head while pulling the old line out evenly from both sides.[1]
Step 5: Thread it through the spool
Pass the line through the spool hole so both ends are the same length.[2]
Step 6: Wind it the right way
Wind both ends tightly and evenly in the direction of the arrows on the spool, side to side without twisting the lines.[2]
Step 7: Leave tails out
Leave about 152 mm (6 inches) of line extending beyond each eyelet.[1]
Step 8: Reassemble and advance the line
Snap the spool back, fasten it, then tap the bump head on the ground while the trimmer runs to feed more line.[1]
The short version
Make the trimmer unable to start, clear out the old line, cut the right length of the right diameter, wind it evenly in the direction the arrows show, and leave short tails out of the eyelets. The exact spool design varies by brand, so keep your manual open: the steps below follow the Toro and ECHO manuals, and your head may differ in how it comes apart.
Before you start
Make sure the trimmer cannot start. Toro's first instruction for changing line is: "Remove the battery pack from the trimmer".[1] For a gas trimmer, follow the same habit as Virginia Cooperative Extension's rule for mowers: "Disconnect the spark or electric plug before troubleshooting or repairing the mower."[3]
Wear safety glasses and gloves. ECHO's manual says: "Wear eye protection that meets ANSI Z87.1 or CE requirements whenever you operate the unit."[2]
Check the line size, which is listed in your manual or on a label on the head or guard. Toro's cordless manual warns: "Do not use any other gauge or type of line, as this could damage the trimmer".[1]
Replacing line on a bump head
On a bump-feed head you often do not need to take the head apart. Toro's cordless manual says: "Remove any existing line on the spool by repetitively pressing the bump head while pulling the line out equally from both sides of the bump head."[1]
Then cut the new line. The same manual says: "Cut a piece of line that is no longer than 7.3 m (24 ft)." It adds: "Do not overload the spool."[1] Thread it so the two ends come out even. On that model you line up the marks on the head with the marks beneath the eyelets, push one end straight through the eyelet until it comes out the other side, and pull through until both sides are equal. Then turn the head in the direction of the arrows to wind the line, and "leave about 152 mm (6 inches) extending beyond the eyelet on each side".[1]
Replacing line on a spool
On a spool-type head, such as the one in the ECHO manual, you take the spool out by turning the knob and separating the parts. ECHO's sheet says: "Thread a 6 m (20 feet) length of 2.4 mm (0.095 in) or 2.7 mm (0.105 in) ECHO line through hole in spool so that ends are the same length."[2] Then "Wind both ends of line tightly and evenly clockwise", side to side, without twisting the lines.[2]
Keep the winding tight. The sheet's instruction is: "Keep line tight on spool."[2] Then: "Snap spool into housing while pulling line through eyelets with about 15 cm (6 in) extending out."[2] Fasten it back with the bolt, spring and knob.
Other brands use different lengths and wind directions, so treat these as examples and follow the arrows on your own spool.
Feeding the line afterwards
Many heads advance line when you tap them. Toro's manual says: "Tap the bump head on the ground to advance the line." It also warns: "Do not hold the bump head on the ground while running the trimmer".[1] If the line has worn too short to feed that way, the same manual says to remove the battery and push the bump head at the base of the spool retainer while pulling on the line.[1]
When restringing does not fix it
A line that keeps breaking or will not feed is often a spool problem: tangled or crossed winds, the wrong diameter, or a worn eyelet with a sharp edge. Rewinding neatly and using the specified line fixes most of these. A damaged head is cheaper to replace than to fight with.
Stop and call a pro if
- The head wobbles or the shaft vibrates after new line. Something is bent or loose.
- The engine will not start or runs badly even with new line. It may be a fuel or ignition problem, so read how much repair costs before spending on parts.
- The head is cracked, or the guard or shaft is damaged. Do not run it.
- You smell fuel or see a leak on a gas trimmer.
Getting help in Virginia
For what a shop would charge, read how much string trimmer repair costs in Virginia, browse small engine repair answers, or find local pros.
When you are ready, describe your trimmer and local small engine shops can quote it.
Common questions
- What size line does my trimmer take?
- The one your manual names. Toro's cordless manual says not to use any other gauge or type of line because it could damage the trimmer. The model number is printed on the shaft or housing, and the manual is free on the maker's website.
- How much line do I cut?
- Follow your manual. One Toro cordless model says to cut no more than 7.3 m (24 ft) and not to overload the spool, while an ECHO gas model's sheet calls for a 6 m (20 feet) length.
- Which way do I wind the line?
- In the direction of the arrows on the spool or the bottom of the head. Both makers' manuals show clockwise on the models cited here, but check yours, because some heads wind the other way.
- Why will the line not feed when I tap the head?
- The line may be worn too short, wound unevenly, or tangled on the spool. Toro's manual says that if the line is worn too short you may not be able to advance it by tapping, and gives a manual advance with the battery removed.
- Do I need to remove the battery or spark plug boot first?
- Yes. Remove the battery on a cordless trimmer, and disconnect the spark plug on a gas one, so the head cannot spin while your hands are on it.
Sources
- [1] Flex-Force Power System 60V MAX String Trimmer, Operator's Manual (Form No. 3469-654), The Toro Company. Checked October 27, 2026.
- [2] Grass Trimmer/Brush Cutter Operator's Manual, model SRM-410U, ECHO Incorporated. Checked October 27, 2026.
- [3] Lawn Care: Rotary Mower Safety (BSE-42P), Virginia Cooperative Extension, Virginia Tech. Checked October 27, 2026.
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