To restring a weed eater spool, you must first remove the spool from the trimmer head and discard the old line. Next, cut a length of replacement line that matches your trimmer’s specified diameter, thread and wind it onto the spool following the directional arrows, and then reassemble the head. While the core process is similar, exact steps vary between bump-feed, fixed-line, and auto-feed heads, so always check your owner’s manual for model-specific details.

Safety First: Before You Begin

Before you start restringing your weed eater, taking a few basic safety precautions is essential to prevent injury.

  • Disconnect the Power: Always disconnect the power source before servicing the trimmer head. For battery-powered models, remove the battery. For corded electric trimmers, unplug the cord. For gas-powered trimmers, remove the spark plug wire to prevent accidental starting.
  • Wear Protective Gear: Wear safety glasses and gloves when handling trimmer line. Cut ends can be sharp, and handling the spool can expose you to small debris.
  • Handle with Care: Be mindful of the trimmer line itself, which can be stiff and springy when coiled. Work in a clear area to avoid tripping or getting tangled.

Identify Your Spool Type

Three types of weed eater trimmer heads displayed on a workbench

The first step is to identify which type of trimmer head you have, as the restringing method differs.

  • Bump-Feed Head (Dual-Line): This is the most common type. It features a spool with two lines that feed out when you bump the head on the ground. It typically has a removable cap and a spool that you wind.
  • Fixed-Line Head (Single-Line): This head uses a single, pre-cut piece of line that is clamped in place. It often has a simpler design with a knob or screw to secure the line.
  • Auto-Feed Head: These heads automatically advance line as you use the trimmer, often using a centrifugal mechanism. They may have a more complex internal design.
  • Solid Spool vs. Split Spool: Some bump-feed heads use a “split spool” design where the spool separates into two halves for winding, while others are a “solid spool” that you wind as a single unit.

You can usually find the correct line diameter specification molded directly on the spool or listed in your owner’s manual. Using the wrong diameter can cause feeding problems or damage the trimmer.

Remove the Spool from the Trimmer Head

Once you’ve identified your head type, you can remove the spool to access the line.

For Bump-Feed Heads

  1. Release the Cap: Most bump-feed heads have a cap that is held on by tabs or a twist-lock mechanism. Look for buttons or tabs on the side of the housing. Press them simultaneously and pull the cap straight off.
  2. Remove the Spool: With the cap off, the spool should lift straight out. Note how the line is threaded through the eyelets (the metal or plastic guides on the housing).

For Fixed-Line Heads

  1. Loosen the Securing Mechanism: Fixed-line heads typically have a knob, screw, or lever that clamps the line. Loosen this to release the old line.
  2. Remove the Line: Pull the old line out completely.

If the cap is stuck, do not force it. Check for a hidden latch or consult your manual. Some heads may require a specific tool, but most are designed for tool-free access.

Remove Old Line and Inspect the Spool

With the spool removed, clear out any remaining old line.

  • Clear Tangles: If the line is tangled or fused together (often from overheating), carefully pull it out. You may need to cut it with scissors.
  • Inspect for Wear: Examine the spool for signs of wear, such as cracked flanges, worn eyelets, or a deformed hub. Worn eyelets are a common cause of line breakage and feed failure.
  • Decide to Replace: If the spool is significantly damaged, it may be more cost-effective to replace the entire spool rather than just restringing it.

Measure and Cut the Replacement Line

Using the correct line is critical for proper function.

  • Confirm Diameter: The correct line diameter is marked on the spool or in the manual. Do not use a different diameter, as it can cause feeding issues or overload the motor.
  • Determine Length: The amount of line you need depends on your spool’s capacity. A general rule of thumb is 10 to 25 feet for a single-line spool, but this varies. It’s better to start with slightly less and add more if needed, as overfilling causes problems.
  • Line Shape: Trimmer line comes in various shapes (round, square, twisted). While you can often use different shapes, be aware that they affect cutting performance and feed behavior. Start with the type that came with your trimmer.

Thread and Wind the Line Onto the Spool

This is the core restringing procedure. The key is to follow the directional arrows molded onto the spool flange.

For a Solid Spool (Single-Line or Dual-Line)

  1. Anchor the Line: Find the starter hole or notch on the spool. Insert the end of the line and secure it.
  2. Wind the Line: Wind the line tightly and evenly in the direction indicated by the arrows. Keep tension on the line to prevent loose loops.
  3. Avoid Cross-Winding: Ensure each wrap lays flat against the previous one. Cross-winding will cause the line to jam.
  4. Do Not Overfill: Stop winding before the line reaches the outer edge of the spool flange. Overfilling causes feeding problems and vibration.

For a Split Spool (Dual-Line)

  1. Separate the Spool: Split the spool into its two halves.
  2. Wind Each Half: Wind each half separately, following the directional arrows. The lines are typically wound side by side or in a figure-eight pattern.
  3. Rejoin the Spool: Once both halves are wound, snap them back together.

For a Fixed-Line Head

  1. Cut a Single Length: Cut one piece of line to the length specified for your head.
  2. Thread and Secure: Thread the line through the eyelet and secure it using the head’s clamping mechanism (knob, screw, etc.). Ensure it is tight.

Reassemble the Spool and Trim the Tails

With the line wound, it’s time to put the spool back together.

  1. Seat the Line: For bump-feed heads, pull the ends of the line through the eyelets on the housing. Some heads require you to align the line with retainer notches on the spool before capping.
  2. Replace the Cap: Align the cap with the housing and press or twist it back into place until it clicks or locks securely.
  3. Trim the Tails: Cut the excess line extending from the eyelets. Leave enough length (a few inches) to engage the feed mechanism, but not so much that it binds.

Test the Feed Mechanism

Before returning to work, test that the line feeds correctly.

  1. Bump Test: For bump-feed heads, hold the trimmer at a safe distance and gently bump the head on the ground (grass or pavement) at low throttle. The line should advance.
  2. Check Function: Observe if the line feeds smoothly. If it doesn’t feed, feeds too much, or causes excessive vibration, there may be an issue with the winding or line diameter.
  3. Adjust if Needed: For fixed-line heads, ensure the line length is appropriate for cutting.

Common Mistakes and Troubleshooting

Here are solutions to frequent problems encountered during restringing.

  • Line Breaks Frequently: This is often caused by using the wrong line diameter, worn eyelets, or overheating from overloading the trimmer with thick weeds.
  • Line Welds Together: This happens when the trimmer is overloaded, causing the line to melt and fuse. Use the correct diameter and avoid forcing the trimmer through dense material.
  • Spool Jams or Rattles: This usually means the line was cross-wound or the spool is overfilled. Remove the spool and rewind it correctly.
  • Line Won’t Feed: Check that the line is threaded correctly through the eyelets and that the spool is seated properly. Ensure the line diameter matches the specification.
  • Using Thicker Line: Using line thicker than specified can overload the motor or clutch, leading to premature wear or failure. Always stick to the recommended diameter.

When to Replace the Entire Head or Spool

Sometimes, restringing isn’t enough. Consider replacement if you see:

  • Structural Damage: A cracked hub, stripped drive splines (the teeth that connect the spool to the trimmer), or missing eyelets.
  • Excessive Wear: If the spool is worn to the point where it no longer holds line securely or feeds properly.
  • Upgrade Considerations: If you frequently deal with tough weeds, you might consider upgrading to a more robust head style. Universal replacement heads are available and fit many straight-shaft trimmers, but they may require an adapter for curved-shaft models.

By following these steps and paying attention to your specific trimmer’s design, you can successfully restring your weed eater spool and get back to work efficiently and safely.