How Do You Refill Weed Wacker Line? (Step-by-Step Guide for Every Spool Type)

Quick Answer: How to Refill Weed Wacker Line

Press the spool cap tabs or unscrew the arbor nut, remove the old spool, cut 15–25 feet of replacement line in the correct diameter for your trimmer, anchor one end in the spool’s slot, wind firmly in the direction marked on the spool housing, thread the free end through the eyelet(s), and snap the cap back until it clicks. Total time: under 10 minutes for a bump feed spool; slightly longer for fixed-line heads that require threading individual segments.

What You Need Before You Start (Line Diameter and Spool Type)

Two decisions made wrong at the start cause most refill failures: using the wrong line gauge and misidentifying your spool type. Resolve both before touching the trimmer.

Choose the Correct Line Diameter

Using a thicker line than the trimmer motor is rated for overloads the head and causes the line to feed poorly or snap at the eyelet. Using a thinner line causes premature wear. Check the label on your trimmer housing or the owner’s manual — the diameter is almost always printed there. If the label is worn, use the table below as a starting guide.

Do not exceed the diameter printed on your trimmer. Thicker line does not cut better on an underpowered motor — it stalls the head and accelerates wear on the drive shaft.

Identify Your Spool Type

Look at the bottom of your trimmer head:

• Bump feed head — Has a rounded plastic cap with a button on the bottom. You tap it on the ground to advance line. Most common type on Ryobi, ECHO, Husqvarna, and Craftsman trimmers. The steps below apply.
• Automatic feed head — Looks like a bump feed head but advances line automatically during use without tapping. The refill method is identical to bump feed.
• Fixed-line head — A star-shaped or indexed plastic disc with individual pre-cut line segments inserted into ports. Common on BLACK+DECKER trimmers and some entry-level models. No winding required; see the fixed-line section below.
• Pre-wound spool — A direct replacement spool purchased pre-loaded with line. Installation is a straight swap requiring no winding at all.

How to Refill a Bump Feed Spool (Most Common Method)

This method covers the majority of string trimmers sold. The entire process runs 5–10 minutes once you have the correct line on hand.

What You Need

• Replacement trimmer line in the correct diameter
• Scissors or a utility knife to cut line cleanly
• Gloves (optional, but nylon line edge can cut skin)

Step 1: Disconnect Power

Remove the battery or unplug the trimmer. For gas models, disconnect the spark plug wire. Never work on a live trimmer head.

Step 2: Remove the Spool Cap

Most bump feed caps release by pressing two side tabs simultaneously and pulling the cap off. Some models — particularly certain Husqvarna and ECHO gas trimmers — use an arbor nut instead of tabs. Turn the arbor nut in the direction indicated by the arrow on the housing; many gas trimmer arbor nuts are reverse-threaded (turn clockwise to loosen) to prevent them from unscrewing during operation. Check your model’s manual before forcing it.

Step 3: Remove the Old Spool and Clear Debris

Lift out the spool and the spring beneath it if present. Note how the spring seats — it must return to the same orientation. Remove any remaining old line and wipe out grass clippings and dirt from inside the head housing. A clogged housing is the most overlooked cause of feed failure after refilling.

Step 4: Cut the Replacement Line

Cut one length of 15–25 feet for a single-line spool, or two equal lengths of 15–20 feet each for a dual-line spool. The spool body usually has a maximum-fill indicator line molded into it — do not wind past it or the cap will not seat properly.

Step 5: Anchor the Line and Wind in the Correct Direction

Insert one end of the line into the anchor slot (a small notch or hole on the spool hub). Pull it snug so it does not slip. Look for the winding-direction arrow molded into the spool or the spool housing — this is the single most-skipped step. Winding in the wrong direction causes the line to unravel inside the head instead of feeding out through the eyelets.

Wind the line in tight, even layers with no crossing or gaps. Loose, haphazard winding causes bird-nesting — line tangling inside the head — which jams the bump mechanism. For a dual-line spool with a center divider, thread one line through the anchor on each side of the divider and wind each half separately in the same marked direction.

Step 6: Leave a Tail and Thread the Eyelet(s)

Stop winding when 5–6 inches of line remain. Hook that tail into the temporary notch on the spool rim (most spools have one) to hold the tension while you work. Pass the free end through the eyelet — the small hole in the trimmer head housing. On a dual-line head, thread one tail through each of the two eyelets. Pull each tail through so 4–5 inches of line extends outside the housing.

Step 7: Reassemble the Head

Replace the spring (if present) in its original orientation. Drop the spool into the housing, aligning any keyed tabs. Press the cap on until you hear or feel it click into both tab locks. Give each line tail a firm tug to confirm it feeds freely and is not pinched by the cap.

Step 8: Trim to Length

Start the trimmer briefly and let centrifugal force trim the line to the cutting blade guard’s length, or manually trim both tails to equal length — roughly 4–5 inches past the head.

How to Refill a Fixed-Line or Pre-Wound Spool Head

Fixed-Line Head (BLACK+DECKER EasyFeed and Similar)

Fixed-line heads use individual pre-cut segments inserted into indexed ports rather than a wound spool. There is no winding step.

1. Disconnect power.
2. Identify the line ports — small indexed holes around the trimmer head disc.
3. Cut individual line segments to the length specified in your manual (typically 6–8 inches per segment).
4. Fold each segment in half and insert the folded center into the port until it locks with a click, or thread one end in from each side of the port depending on head design.
5. Pull each segment to confirm it is seated. Both tails should extend equally.
6. No cap to reassemble — the head is ready to use.

Can you convert a fixed-line head to a bump feed head? On some trimmer models, yes — aftermarket universal bump feed heads are available that thread onto the same arbor. Check that the arbor thread pitch and diameter match before purchasing a conversion head.

Pre-Wound Replacement Spool

Pre-wound spools are the fastest reload option. Purchase a spool wound with the correct line diameter for your model (many brands sell these as accessories). Remove the old spool following Steps 1–3 above, drop in the pre-wound spool, thread the tail(s) through the eyelet(s), and snap the cap back on. No cutting or winding required. Pre-wound spools cost more per foot of line than bulk line but save roughly 5 minutes per refill.

Brand-Specific Differences to Watch For

Ryobi

Most Ryobi bump feed heads use a press-tab cap — squeeze both tabs simultaneously and pull down. The cap does not twist. Ryobi’s AC14RL3A line (0.065 in) and AC80RL3 (0.080 in) are the two most common gauges across their battery platform. The spool winding arrow is molded into the inner spool body, not the outer housing — look inside the spool chamber, not at the cap.

ECHO

Many ECHO Speed-Feed heads use a twist-to-release cap rather than tabs — rotate the cap in the direction marked by the arrow, then pull off. ECHO’s Speed-Feed 400 head has two separate line chambers on a single spool; each chamber accepts one strand of a dual-line setup. Wind each strand independently in the same direction. Do not combine both strands in one chamber.

Husqvarna

Husqvarna gas trimmer arbor nuts are commonly reverse-threaded on straight-shaft models — turn clockwise to loosen. Confirm this by checking the arrow or the text on the guard near the head before applying force. The T25 and T35 tap-advance heads on Husqvarna trimmers use a press-and-twist cap: press down on the cap, rotate it to the unlock symbol, then lift off.

BLACK+DECKER

Most BLACK+DECKER corded and battery trimmers use a fixed-line AFS (Automatic Feed System) head rather than a traditional wound spool. The cap on AFS heads twists counterclockwise to remove. Replacement line cartridges (pre-cut segments in a dispenser) are the easiest reload option for this system. Standard bulk line can be cut to length and used instead to reduce cost.

Troubleshooting: Why the Line Won’t Feed, Breaks Immediately, or Gets Welded

Line Does Not Advance When You Tap the Bump Head

Root cause: Line wound past the maximum-fill line on the spool, or wound in the wrong direction. Remove the spool, unwind until the fill level is below the indicator ring, and confirm winding direction matches the arrow. Also check that the spring beneath the spool is present and correctly seated — a missing spring disables the bump mechanism entirely.

Line Snaps at the Eyelet Immediately

Root cause: Line diameter too thin for the cutting conditions, or the eyelet edge has a burr or crack that cuts the line under tension. Try the next diameter up if conditions are heavy. Inspect the eyelet with your finger — a rough edge requires filing smooth or replacing the eyelet grommet, which is available as a spare part for most heads.

Line Fuses Together on the Spool (Welding)

Root cause: Line wound too loosely, allowing layers to shift and compress under the heat generated during cutting. The friction of overlapping layers melts the nylon surfaces together. Wind the replacement line in tight, consistent layers with firm tension throughout. Store unused line away from direct sunlight and heat sources — UV exposure and heat degrade nylon and make it more prone to fusing.

Line Tangles Inside the Head (Bird-Nesting)

Root cause: Uneven or crossing winds on the spool. When layers cross, the advancing line catches on itself instead of feeding through the eyelet. Rewind with deliberate side-by-side layers, no overlapping, and no slack in the line as you wind.

Line Feeds Too Far and Wraps Around the Head

Root cause: Bump head tapped too forcefully or too many times in succession, or the spool spring is too weak to retract the line. Tap once per advance — a single firm tap on flat ground is sufficient. If the spring is stretched or compressed out of spec, replace it; springs for common heads cost under $3.

How to Make Trimmer Line Last Longer Between Refills

Store Line Correctly

Nylon trimmer line loses flexibility when exposed to UV light and heat, making it brittle and prone to breaking at the eyelet. Store unused line in a sealed bag or airtight container away from direct sunlight and out of hot storage areas like garages in summer. Some trimmer manufacturers recommend storing line in a cool, damp environment to maintain nylon flexibility — soaking dried-out line in water for 24 hours before use can partially restore flexibility in line that has become brittle from improper storage, though this is a workaround, not a substitute for proper storage.

Avoid Concrete and Hard Surfaces

Trimming along concrete curbs, brick edging, and fence posts wears line 3–5 times faster than cutting grass. Use a dedicated edger for hard borders, or raise the trimmer head slightly when working near hard surfaces so only the line tip — not the mid-section — contacts the material.

Cut at the Correct Height

Holding the trimmer head too low causes the line to strike the ground repeatedly, wearing it down from the tip inward and triggering more frequent bump advances. Keep the cutting plane 2–3 inches above the soil surface. The line cuts with its tip — you do not need the full extended length making contact to cut effectively.

Refill Frequency Under Normal Use

For a typical residential lawn trimmed once per week, a single bump feed spool refill with 20 feet of 0.080 in line lasts 2–4 trimming sessions depending on yard size, obstacle density, and line diameter. Keeping a spare pre-cut length stored with the trimmer eliminates mid-session delays.

Frequently Asked Questions

How do I know what size trimmer line my weed wacker takes?

The correct line diameter is printed on a label on the trimmer shaft or head housing on most models. It is also listed in the owner’s manual and on the manufacturer’s website under your model number. If the label is gone, start with 0.080 in for a mid-range battery trimmer or 0.095 in for a gas trimmer, and confirm against the manufacturer’s spec before purchasing in bulk.

How much line should I put on a trimmer spool?

Cut 15–25 feet of line per spool fill for most residential bump feed heads. Wind until the line reaches — but does not exceed — the maximum-fill indicator molded into the spool wall. Overfilling prevents the cap from seating and causes the line to jam rather than advance.

Why does my trimmer line keep breaking right after I refill it?

The three most common causes are: (1) line diameter too thin for the cutting conditions, (2) a cracked or burred eyelet that cuts the line under load, or (3) old brittle line that lost flexibility from UV or heat exposure during storage. Check the eyelet for damage, confirm you are using the diameter specified for your trimmer, and use fresh line from a sealed package.

Is it cheaper to refill a spool with bulk line or buy pre-wound replacement spools?

Bulk line is significantly cheaper per foot — typically $0.05–0.15 per foot versus $0.30–0.60 per foot for branded pre-wound spools. For frequent users, a 100-foot or 500-foot spool of bulk line in the correct diameter pays back its cost within 3–5 refills. Pre-wound spools are worth the premium for infrequent users or anyone who finds winding difficult.