How to Replace Weedwhacker Line
To replace weedwhacker line, disconnect the power source, press the tabs on the spool housing to remove the spool, cut new line to the length specified in your manual, wind it onto the spool following the arrow direction, thread the ends through the eyelets, and snap the spool back into the housing.
- Time
- 10 min
- Frequency
- as needed (when line runs out)
- Difficulty
- easy
- Cost
- $5
What you'll need
- Replacement trimmer line
- Scissors or utility knife
The steps
- 1
Disconnect power
Unplug an electric trimmer or remove the battery. For gas trimmers, let the engine cool and disconnect the spark plug wire. This prevents accidental starts while your hands are near the trimmer head.
- 2
Press tabs on spool housing and remove the spool
Most trimmer heads have two tabs on opposite sides of the housing. Press both tabs inward simultaneously and pull the spool cover off. Lift the spool out of the housing. On some models, you twist the cover counterclockwise instead of pressing tabs. Check your manual if the head does not come apart easily.
- 3
Clean inside the housing
Wipe out grass clippings, dirt, and old line fragments from inside the housing and spool. Debris packed in the housing prevents the spool from spinning freely and can jam the line feed mechanism. A clean housing means smoother line feeding during use.
- 4
Cut new line to length
Check your manual for the recommended line length (typically 9 to 15 feet per side depending on spool capacity). Cut the line from the bulk roll. For dual-line heads, cut two equal pieces. Cutting too long wastes line because excess cannot fit on the spool. Cutting too short means frequent reloading.
- 5
Wind line onto spool following arrow direction
Most spools have an arrow stamped or molded into the plastic indicating the winding direction. Insert one end of the line into the anchor hole on the spool and wind in the direction of the arrow, keeping the wraps tight and even. Do not overlap or cross the line — messy winding causes jams. Leave about 6 inches of line unwound.
- 6
Thread ends through eyelets
Feed the free end of the line through the eyelet (small hole) in the spool housing. For dual-line heads, thread each line through its respective eyelet on opposite sides of the housing. Make sure the lines exit cleanly without kinking.
- 7
Snap spool back into housing and test
Place the spool back into the housing with the spring underneath (if applicable). Press the cover back on until the tabs click. Pull each line firmly to make sure they feed smoothly. If a line is stuck, remove the spool and check for crossed wraps or debris. Reconnect power and do a quick test run.
Line diameter matters
Trimmer line comes in a range of diameters, and using the right one for your machine is important. Light electric trimmers typically use .065 inch line. Mid-range trimmers use .080 inch. Heavy-duty gas trimmers can handle .095 to .105 inch line. Your manual or the spool itself lists the maximum diameter.
Using line that is too thick overloads the motor on electric models and jams the spool housing. Using line that is too thin breaks on contact with anything harder than grass and wears out rapidly. Match the line diameter to your trimmer, not to the job — the machine is designed around a specific size.
Line shape also varies. Round line is the most common and works for general trimming. Square and star-shaped lines cut heavier growth more aggressively. Twisted line reduces noise. For most homeowners trimming around a lawn, standard round line in the correct diameter is all you need.
Winding direction
Every spool has a correct winding direction, and it matters. The arrow on the spool indicates which way to wrap the line. Winding the line in the right direction means the spool's rotation feeds line outward smoothly. Winding backward means the spool's rotation tightens the line against itself, preventing it from feeding and causing jams.
Wind the line in tight, even rows. Do not overlap strands or let the line cross over itself. Messy winding is the most common cause of line jams — the crossed strands lock together under centrifugal force and the line stops feeding. Take an extra minute to wind neatly and you will avoid stops in the middle of trimming.
Pre-wound spools vs bulk line
Pre-wound replacement spools are the easy option. Pop the old spool out, drop the new one in, and you are trimming in 30 seconds. The downside is cost — a single pre-wound spool costs $5 to $12, and a typical homeowner goes through 4 to 8 per season.
A 200-foot roll of bulk trimmer line costs $10 to $15 and refills the spool 10 to 20 times depending on your spool capacity. The per-refill cost drops to well under $1. The tradeoff is the 5 to 10 minutes it takes to wind the line by hand.
For occasional use, pre-wound spools are fine. For weekly trimming, bulk line pays for itself within a season and you always have line on hand when you run out mid-job.
Bump feed vs auto feed
Most homeowner trimmers use a bump feed head — you tap the bottom of the head on the ground while the trimmer is running, and the spool releases a short length of line. This gives you control over how much line is out at any time.
Auto feed heads sense when the line is short and release more automatically. They are more convenient but can overfeed, which wastes line and reduces cutting speed. Some auto feed heads are also harder to restring manually.
Regardless of feed type, the line replacement process is the same: remove the spool, wind new line, and reinstall. The only difference is the mechanism that releases the line during use.
Frequently asked questions
- What diameter trimmer line should I use?
- Check your trimmer's manual or the spool itself for the recommended diameter. Common sizes range from .065 inch for light electric trimmers to .095 inch for heavy-duty gas models. Using line that is too thick can overload the motor or jam the head. Using line that is too thin cuts poorly and breaks frequently.
- Which direction do I wind the line?
- Follow the arrow stamped on the spool. The arrow shows the correct winding direction, which is the opposite of the spool's rotation direction. Winding against the arrow causes the line to unravel during use instead of feeding properly. If there is no arrow, check your manual.
- Are pre-wound spools worth the extra cost?
- Pre-wound spools cost $5 to $12 each depending on the model. A bulk roll of trimmer line costs $8 to $15 for 100 to 200 feet — enough to refill the spool 10 to 20 times. If your time is worth more than the savings, pre-wound spools are convenient. If you trim frequently, buying bulk line and winding your own saves significant money over a season.
- Why does my trimmer line keep breaking?
- The most common causes are hitting hard surfaces (concrete, fences, rocks), using line that is too thin for the job, and old brittle line that has dried out. Trimmer line degrades in sunlight and heat even while stored. Keep bulk line in a cool, dark place. Soaking old line in water overnight can restore some flexibility.
Products you'll need
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Weedwhacker Trimmer Line (check model)
Line diameter varies by model — check manual
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