Replace the spool when the line runs out or breaks

Weedeater line wears down as you use it, and when it gets too short or snaps, you need to wind new line onto the spool or swap in a fresh spool. The exact steps depend on whether your trimmer has a fixed spool you reload or a bump-feed head where you replace the whole cartridge. Most residential trimmers use one of these two designs, and the process takes less than five minutes once you know which one you have.

Before you start, unplug the trimmer or remove the battery so it cannot accidentally start. Let the engine cool if you have been using it. You will need replacement line — usually 0.080 or 0.095 inches in diameter, depending on your model — and you may need a small screwdriver or wrench to open the head.

Key Takeaways

  • Unplug the trimmer or remove the battery before opening the head to prevent accidental starting.
  • Bump-feed heads (the most common type) require you to replace the entire spool cartridge, which snaps in and out by hand.
  • Fixed spools require you to wind new line by hand or use a line-winding tool, then thread the ends through the eyelets.
  • Most trimmers use 0.080 or 0.095-inch line; check your manual or the old spool to confirm the diameter.
  • After loading new line, test the trimmer at low speed to make sure the line feeds correctly before full use.

Identify whether you have a bump-feed or fixed spool

Look at the bottom of the trimmer head. A bump-feed head is a rounded cartridge that looks like a single sealed unit; you tap it on the ground to release more line as it wears. A fixed spool is a flat or slightly domed cap with visible line wound around it underneath, and you can usually see the line ends sticking out through small eyelets or slots.

Bump-feed heads are far more common on consumer trimmers. If you are unsure, check your owner's manual — it will show a diagram and tell you which type you have. The manual also lists the correct line diameter and how much line the spool holds.

Replace a bump-feed cartridge

Hold the trimmer head steady and look for a notch or tab on the side of the cartridge. Rotate the cartridge counterclockwise (or follow the arrow printed on the head) until the cartridge loosens, then unscrew it by hand and lift it away. Some models require you to press a button or release a clip instead — your manual will show which.

Take the new cartridge out of its packaging. Line it up with the shaft inside the head and push it in until it seats fully, then rotate it clockwise until it stops and is snug. Do not overtighten. Plug in the trimmer, hold it over a trash can or outside, and tap the bump knob on the ground a few times to feed out fresh line. Trim a small patch of grass to confirm the line is feeding and cutting correctly.

Wind new line onto a fixed spool

Remove the spool cap by turning it counterclockwise or unbolting it with a wrench — your manual shows which. Lift off the cap and the old spool. Clean out any grass or debris from inside the head.

Cut a length of new line — usually 15 to 20 feet, depending on spool size — and find the center point. Insert the center into the anchor hole or slot in the middle of the spool (your manual shows where this is). Wind the line tightly and evenly around the spool in the direction marked by an arrow on the spool itself. Keep tension as you wind so the line does not bunch or overlap.

Once the spool is full, leave about 6 inches of line free on each side. Thread one end through the left eyelet and one end through the right eyelet. Slide the spool back into the head, align the cap, and screw it back on hand-tight. Trim the line ends so they stick out about 2 inches beyond the eyelets.

Use a line-winding tool if you have one

Some trimmers come with a plastic winding tool that makes loading line faster and more even. Insert the line into the slot on the tool, then turn the handle to wind the line onto the tool's spool. Once wound, snap the tool's spool into the trimmer head in place of the old one, or transfer the wound line to your trimmer's spool if the tool is separate.

If you lost your winding tool, you can wind by hand following the steps above, or you can order a replacement tool from the trimmer manufacturer. Hand-winding works fine and takes only a few extra minutes.

Test the trimmer before full use

After loading new line, plug in the trimmer and hold it away from your body and face. Start it at the lowest speed setting and listen for the line to feed smoothly. If the line does not come out or feeds unevenly, stop, unplug, and check that the line is threaded through both eyelets and that the spool is seated all the way in the head.

Once the line feeds smoothly, move to a small patch of grass and make a few test cuts at low speed. The line should cut cleanly without stuttering or breaking. If it breaks repeatedly, the line diameter may be wrong — check your manual and confirm you are using the correct size.

Frequently Asked Questions

What line diameter do I need?

Check your trimmer's manual or look at the old spool — the diameter is usually printed there. Most residential trimmers use 0.080 or 0.095 inches. Using the wrong size can cause feeding problems or poor cutting. Line is sold by diameter, so confirm before you buy.

Can I use any brand of replacement line?

Yes. Replacement line is a standard product and works across brands as long as the diameter matches your trimmer. You do not need to buy the original manufacturer's line — hardware stores and online retailers sell compatible line at lower cost.

How often do I need to replace the line?

It depends on how often you trim and how thick the weeds are. Light residential use may require a new spool every few months; heavy use may need it every few weeks. You will know it is time when the line becomes too short to cut effectively or breaks during use.

What if the line keeps breaking?

Check that you are using the correct diameter — wrong size line breaks easily. Also make sure the line is wound evenly with no kinks or overlaps, and that it is threaded through both eyelets. If it still breaks, the spool or head may be damaged and need replacement.

Do I need to empty the old line before loading new line?

On bump-feed heads, you simply replace the cartridge, so old line is discarded with it. On fixed spools, remove the old line first — unwind it or cut it away. Do not try to wind new line over old line; it will not feed correctly.