Direct Answer: How to Change Weed Eater String
To change the string on a weed eater, remove the spool cap (usually by twisting counterclockwise), take out the empty spool, and wind new trimmer line onto a replacement spool in the direction indicated by arrows on the spool. Most bump-feed trimmers use 0.080″ to 0.105″ diameter line; cut a length of 15–20 feet, fold it in half, and wind both strands together. Once wound, reinsert the spool, thread the line through the eyelets on the head, and replace the cap. Your trimmer is then ready to use.
Understanding Weed Eater String Replacement
When people ask about “changing the string” on a weed eater, they’re typically referring to replacing the trimmer line (also called string, cord, or line) that spins to cut grass and weeds. This is different from replacing the entire spool assembly or trimmer head, though the line itself wears out fastest and needs regular replacement.
The trimmer line gradually shortens as you use your weed eater—it strikes hard surfaces, breaks into pieces, and gets consumed during normal operation. Most users notice the cutting diameter shrinking within a few uses or after a few hours of work. When the line gets too short to be effective, you need to restring the spool with fresh line.
Why you need to replace trimmer line:
- Line wears down and breaks naturally during use
- Worn or short line reduces cutting effectiveness
- Continuing to use a trimmer with inadequate line can strain the motor
- Restringing is far cheaper than replacing the entire trimmer head
There are two main types of trimmer heads you’ll encounter: bump-feed heads (the most common) where you feed new line as the old line breaks, and fixed-line heads with pre-wound spools. This guide focuses on bump-feed heads, which account for the majority of consumer-grade weed eaters.
Choosing the Right Trimmer Line for Your Weed Eater
Before you begin restringing, you need to select the correct trimmer line for your specific model. Using the wrong type or diameter can affect cutting performance and may damage your trimmer.
Line Diameter Options:
Trimmer line comes in several standard diameters, measured in inches. The most common sizes are:
- 0.065″ – Lightweight trimmers and electric models; best for thin grass and light weed trimming
- 0.080″ – Mid-range gas and electric trimmers; versatile for most residential use
- 0.095″ – Heavy-duty gas trimmers; handles tougher vegetation and brush
- 0.105″ – Professional-grade trimmers; designed for dense weeds and small brush
Check your trimmer’s manual or the spool assembly for the recommended diameter. Most residential gas trimmers use 0.080″ or 0.095″ line. If you’re unsure, 0.080″ is a safe, universal choice for general yard maintenance.
Line Material:
Trimmer line is made from various materials. Standard nylon line is the most common and cost-effective. Spiral-wound and twisted lines offer slightly more durability but cost more. For most homeowners, standard nylon line is sufficient and performs well.
How to Find Your Trimmer’s Specifications:
- Check the owner’s manual (usually lists recommended line diameter and length)
- Look for specifications printed on the spool cap or the trimmer head itself
- Contact the manufacturer with your trimmer model number
- Visit the manufacturer’s website for your specific model
Step-by-Step: How to Change Weed Eater String
Step 1: Prepare Your Work Area and Gather Materials
Before you start, make sure your trimmer is unplugged (if electric) or the fuel is off and the engine has cooled (if gas). You’ll need:
- New trimmer line (correct diameter for your model)
- Scissors or line cutter for cutting the cord
- A small screwdriver or wrench (if your trimmer requires tools to remove the spool cap)
- A clean work surface
- Your trimmer manual for reference (optional but helpful)
Step 2: Remove the Spool Cap
Most bump-feed trimmer heads have a plastic cap on top. The cap is usually secured by twisting it counterclockwise. Grip the spool cap firmly and turn it counterclockwise until it comes free. Some models have a small arrow or line indicating the direction to turn. If the cap is stuck, use a rubber rag for better grip—do not force it, as plastic can crack.
Once the cap is off, you’ll see the spool inside. Some trimmers allow you to remove the spool easily; others may have the spool permanently attached to the head. If your spool is removable, lift it straight up and out.
Step 3: Remove the Old Line
If there’s any old line on the spool, pull it off and discard it. Most old line will come away in pieces or as a tangled mass. Remove all debris and clean out any dirt or grass clippings from the spool. If you can see old line wound around the spool, unwind it completely until the spool is clean.
Step 4: Measure and Cut New Line
Cut a length of new trimmer line. The standard length for most residential bump-feed heads is 15–20 feet. A good rule of thumb is to cut a length roughly equal to the height of your trimmer head (measured in feet). For example, if your trimmer head is about 4 inches wide, cut 20 feet of line.
If you’re unsure of the correct length, start with 15 feet. You can always cut more if needed. Trim the line straight across with scissors or a line cutter—a clean cut makes winding easier.
Step 5: Fold and Prepare the Line
Fold the line in half to create a loop. This creates two strands that will wind onto the spool together. Hold the loop in one hand and the two ends in the other. Some trimmers have a small notch or guide on the spool where you insert the loop—check your spool for this feature.
Step 6: Wind the Line onto the Spool
This is the critical step. Look at the spool for arrows or directional markings indicating which way to wind the line. Always wind the line in the direction the arrow points. Winding in the wrong direction means the line won’t feed properly when you use the trimmer.
Winding technique:
- If your spool has a notch for the loop, insert the folded line into the notch first
- Begin winding the two strands together around the spool in the direction indicated by the arrow
- Keep tension on the line as you wind—it should be snug but not stretched to the breaking point
- Wind neatly in layers, ensuring each wrap sits next to the previous one without overlapping or crossing
- Leave about 6 inches of line free on each end (these will feed out through the eyelets)
Most spools can hold 15–20 feet of line without issue. If you’ve wound a significant amount and the spool is nearly full, stop. Overfilled spools won’t fit back into the trimmer head.
Step 7: Thread the Line Through the Eyelets
Once the line is wound on the spool, you need to thread the two free ends through the eyelets (small holes) on the trimmer head. These eyelets are usually located on opposite sides of the head. Pull each free end through its corresponding eyelet. You should have roughly equal lengths of line extending from each side—typically 4–6 inches on each side.
This is the line that will actually cut grass, so make sure it’s positioned correctly before reassembling.
Step 8: Reinsert the Spool and Reassemble
Carefully place the wound spool back into the trimmer head, making sure the line feeds through the eyelets smoothly. If the spool is removable, push it down into its seat until it clicks or seats firmly. Replace the spool cap by twisting it clockwise until it’s snug. Don’t over-tighten—you just want it secure enough that it won’t vibrate loose during use.
Step 9: Trim the Line to Cutting Length
Most trimmers have a plastic blade or guide on the head that indicates the correct cutting line length. The line extending from each eyelet should typically be around 2–4 inches. Use this blade as a guide and trim any excess line with scissors. Some trimmers have the blade as a separate piece you can use to measure, while others have it molded into the head.
Step 10: Test Before Full Use
Before using your trimmer on a full yard, test it briefly at low speed. Turn it on for a few seconds to ensure the line is feeding properly and spinning freely. If the line doesn’t spin or seems tangled, stop immediately and recheck your winding. If everything looks good, you’re ready to trim.
Troubleshooting Common String Replacement Issues
Line Won’t Feed Properly
Problem: You’ve restrung the trimmer, but the line doesn’t rotate or rotates sluggishly.
Solutions:
- Check that you wound the line in the correct direction (follow the arrow on the spool)
- Ensure the spool cap is not too tight—it should be snug but not crushed down
- Verify that the line is threaded correctly through the eyelets
- Look for tangles or twisted line on the spool and unwind to fix
- Clean out any debris or grass clippings blocking the head or spool
Line Breaks Immediately After Replacement
Problem: You’ve installed new line, but it breaks within the first few uses.
Solutions:
- Check that you’re using the correct line diameter for your trimmer
- Inspect the trimmer head for cracks, sharp edges, or burrs that might cut the line—sand down any rough spots
- Make sure the line isn’t over-wound and too tight on the spool
- Verify you haven’t accidentally used a line diameter that’s too thin for your model
- Test the trimmer head for bent or misaligned eyelets
Spool Cap Won’t Close or Fit
Problem: After restringing, the spool cap won’t fit back on or close properly.
Solutions:
- Check that the spool is not overfilled with line—remove some and rewind if necessary
- Make sure the spool is fully seated in the head before replacing the cap
- Verify that the line isn’t bunched up or sticking out of the spool
- Clean any debris from the cap threads and spool housing
- Inspect the cap and spool for cracks or damage that might prevent a proper fit
Line Tangled or Wound Unevenly
Problem: After winding, the line is twisted, knotted, or wound in an uneven pattern.
Solutions:
- Unwind the line completely and start over, ensuring you maintain consistent tension
- Wind more slowly and deliberately, checking each wrap as you go
- Make sure the loop is properly seated in the spool notch before beginning
- Avoid pulling the line too tightly—it should be snug but not stretched
Frequently Asked Questions
How often do I need to change the string on my weed eater?
This depends on how often you use your trimmer and the type of vegetation you’re cutting. A typical homeowner might need to restring every 2–4 weeks during the growing season if using the trimmer once weekly. Heavy users or those dealing with thick brush may need to restring every week or every few uses. You’ll know it’s time when the line becomes noticeably shorter and the cutting performance drops.
Can I use any diameter of trimmer line on my weed eater?
No. Using the wrong diameter can affect performance and may damage your trimmer. Using line that’s too thick strains the motor and head, while line that’s too thin breaks easily and won’t cut effectively. Always consult your manual for the recommended diameter. If you’re unsure, contact the manufacturer or check their website.
Why does my trimmer line keep breaking?
Line breaks for several reasons: hitting hard surfaces like rocks or concrete, using line that’s too thin for your trimmer model, the trimmer head being damaged or having sharp edges, or the line being wound too tightly on the spool. Inspect your head for damage, verify you’re using the correct diameter, and ensure the line is wound with consistent but not excessive tension.
How much line should I leave extending from the trimmer head after restringing?
Typically, you should leave 4–6 inches of line extending from each eyelet before the first use. Your trimmer’s plastic cutting blade (usually on the side of the head) serves as a guide—trim the line level with this blade. Once you start using the trimmer, you’ll use the bump-feed mechanism to extend more line as it wears down.
What’s the difference between bump-feed and fixed-line trimmer heads?
Bump-feed heads (the most common) let you feed out new line by tapping the head on the ground as the existing line wears. Fixed-line heads have line that’s pre-wound and secured, and you typically replace the entire spool assembly rather than restring it. Most residential weed eaters use bump-feed heads, which are easier and cheaper to maintain.
Key Takeaways
Restringing a weed eater is a simple, 10–15 minute task that requires only basic tools and the correct trimmer line for your model. The most critical steps are confirming the correct line diameter, winding the line in the direction indicated on the spool, and ensuring proper feeding through the eyelets. If you follow the manufacturer’s recommendations and take care to wind neatly with consistent tension, your trimmer will be ready for dependable cutting. Regular restringing keeps your equipment in top condition and is far more cost-effective than replacing the trimmer head.
