Quick Answer: How to Change Weedeater String
To change weedeater string, first disconnect the power source (unplug electric models or remove batteries). Locate and remove your trimmer head by unscrewing the center bolt or releasing a cartridge. Remove the old string, then measure and cut new nylon string to the length specified in your manual (typically 15-30 feet depending on spool size). Wind the new string tightly around the spool following the directional arrows, leaving 4-6 inches unwound for cutting edges. Reinstall the spool, thread the string ends through the eyelets, trim to proper length, and test your feed system before use.
Understanding Your Weedeater’s String System
Before you begin replacing string, identify which type of feeding system your weedeater uses. This determines your exact replacement process and how the string loads into the trimmer head.
Three Main Types of Weedeater Feed Systems
- Manual Spool Winding: You manually wind string onto a removable spool. Most common on budget and mid-range models. Requires careful winding technique for proper feed.
- Bump-Feed System: A semi-automatic system where tapping the trimmer head on the ground releases pre-wound string. Requires proper initial winding and adequate string length for automatic feed.
- Automatic Feed System: Advances string automatically as it wears. Typically found on premium models and requires loading string into a cartridge rather than manual winding.
Check your weedeater’s manual or inspect your trimmer head to determine which system you have. The manual also contains critical specifications like string gauge (diameter) and spool capacity (total string length).
Essential Safety Precautions
- Disconnect all power: Unplug electric corded models or remove rechargeable batteries. For gas models, ensure the engine is completely cool and disconnect the spark plug wire.
- Allow the trimmer head to stop completely: Never work on a trimmer head while it has residual spin.
- Work on a flat, stable surface: Stabilize the trimmer between your legs or in a vice to prevent rolling during spool removal.
- Wear safety glasses: Small parts and old string fragments can become projectiles.
Essential Information Before You Start
Determining the Correct String Gauge and Type
String comes in different diameters (gauges), commonly ranging from .065 inches to .130 inches. Using the wrong gauge can cause poor cutting performance, feed issues, or damage to your trimmer head.
To find the correct specification:
- Check your weedeater’s user manual—this is the most reliable source
- Look for markings on the trimmer head or spool itself, which often displays gauge information
- Consult the manufacturer’s website using your exact model number (usually found on the deck or handle)
- Contact the manufacturer’s customer service if documentation is unavailable
Most common residential weedeaters use .080 or .095-inch gauge nylon string. Commercial-grade models often require .105 or .130-inch string. Never substitute with thinner string, as it will break frequently; thicker string than recommended may not feed properly or could strain the motor.
How Much String Do You Need?
String spool capacity varies by model. Check your manual for the exact length your spool accommodates. As a general guide:
- Compact residential trimmers: 15-20 feet of string per spool
- Standard residential trimmers: 20-30 feet of string per spool
- Commercial-grade trimmers: 30-50+ feet depending on head design
Purchase slightly more string than your spool capacity to account for winding mistakes or future replacements. Most retailers sell string on spools of 100+ feet.
Step-by-Step: Removing the Old String
Accessing the Trimmer Head
The method depends on your trimmer head design:
For screw-on heads: Locate the center bolt at the bottom of the trimmer head. Using the appropriate wrench or socket (typically 8-10mm), turn counterclockwise to loosen. Most weedeaters use reverse threads on the left side, so you may need to turn clockwise instead—check your manual. Once loose, hand-rotate to remove the entire spool assembly.
For cartridge-style heads: These snap into the trimmer housing. Press the release tabs on either side of the cartridge and pull straight down to remove the entire cutting head assembly. This design is common on newer Ryobi, Makita, and DeWalt models.
For bump-feed heads: Most bump-feed systems use a removable spool cover accessed from the bottom. Flip the trimmer upside down and locate the spool cover—often held by a single bolt in the center or snap tabs around the perimeter. Remove according to your manual’s instructions.
Removing the Old String
Once you’ve accessed the spool:
- Pull away any remaining old string manually—it typically pulls free easily once the spool is accessible
- If string is tightly wound, use needle-nose pliers to pry up the end and unwind
- Inspect the spool for cracks, worn edges, or burrs that could catch new string; replace the spool if damaged
- Wipe the spool clean with a dry cloth to remove dirt and debris
Step-by-Step: Preparing and Loading New String
Measuring the Correct Length
Accuracy here prevents winding problems and ensures you load enough string for optimal cutting performance.
Method 1 (Most Accurate): If you have the old string available, measure its length. This is precisely what your spool accommodates.
Method 2 (Using Manual Specifications): Your user manual specifies total string length. Cut string to this exact measurement.
Method 3 (Physical Measurement): If you lack specifications, start with 20-25 feet for standard residential models. Wind it onto the spool; if space remains, add 5-foot increments until the spool is full without bulging.
Preparing the String for Winding
- Cut the string on a flat surface using sharp scissors or a utility knife to create clean, straight edges
- If your string has a center marking or loop (provided on some spools), fold the string at its midpoint and begin winding from the fold—this helps prevent tangling
- Alternatively, begin winding from one end and work toward the other, creating two cutting edges
Step-by-Step: Winding String on the Spool
Understanding Wind Direction
The spool has directional arrows indicating which way to wind. Always follow these arrows precisely. Winding in the wrong direction prevents the string from feeding correctly and creates tangled string that jams the head.
Most spools indicate counterclockwise or clockwise winding with printed arrows. If arrows are worn or unclear, consult your manual—it will specify the correct direction for your exact model.
The Winding Technique
Step 1: Position the spool so you can see the directional arrows clearly. Hold the string end against the spool where the winding begins (typically marked with a small notch or groove).
Step 2: Begin winding tightly and evenly across the spool width. Maintain consistent tension—not so loose that string sags, but not so tight that you struggle to wind. Aim for firm, controlled winding.
Step 3: Wind in neat, overlapping passes across the spool. Each wrap should sit snugly against the previous wrap without crossing over or creating gaps. This prevents string from jamming or tangling during feed.
Step 4: As you approach the rim of the spool, leave the final 4-6 inches of string unwound and free. This creates the two cutting edges that extend from the spool.
Step 5: If your spool has notches or grooves at the rim, insert the final string ends into these notches to hold them in place during reassembly. If no notches exist, the string ends will be threaded through eyelets on the trimmer head housing.
Common Winding Mistakes to Avoid
- Winding too loosely: Causes the string to slip and not feed properly. Wind firmly until you feel resistance.
- Crossing wraps over each other: Creates knots and jams. Keep wraps parallel and adjacent.
- Leaving too much free string: Can cause the string to flail wildly during operation. Keep final edges to 4-6 inches.
- Leaving too little free string: Prevents adequate cutting edges. Ensure at least 3-4 inches per side minimum.
- Winding in the wrong direction: The most common cause of feed failure. Double-check arrows before starting.
Step-by-Step: Reassembling and Testing
Reinstalling the Spool
For screw-on heads: Position the wound spool back into the trimmer head housing. Ensure the center shaft aligns with the spool hole. Hand-thread the center bolt clockwise (or counterclockwise if specified in your manual) until snug. Do not over-tighten, as this can strip threads or damage the spool.
For cartridge-style heads: Align the cartridge with the trimmer housing slots. Push upward firmly until you hear or feel a click indicating the cartridge is fully seated and locked.
Threading String Through Eyelets
Most trimmer heads have two eyelets (small holes) on opposite sides of the housing. The free string ends feed through these eyelets to create the cutting edges.
- Locate the eyelets on your trimmer head housing
- Pull one string end through one eyelet
- Pull the other string end through the opposite eyelet
- Ensure both ends are fed completely through and not pinched in the housing
Trimming to Proper Cutting Length
The string extending from the eyelets is now trimmed to the proper cutting length. This is typically 4-6 inches per side, but check your manual for your specific model’s recommendation.
- Using sharp scissors or a utility knife, trim each string end to the specified length
- Make straight cuts perpendicular to the string for clean cutting edges
- Slightly unequal lengths (within 1/2 inch) will automatically balance as the string wears
Testing the Feed System
For bump-feed systems: Reconnect power and hold the trimmer level. Gently tap the spool head on a flat surface (such as concrete). You should hear or feel a slight click as the mechanism advances. The string should gradually move outward. If nothing happens, the string may be too tightly wound or not seated in the notches correctly.
For automatic feed systems: Reconnect power and run the trimmer for a few seconds. Watch the cutting head to ensure string advances smoothly. If string doesn’t advance, check that you’ve loaded the cartridge correctly and that the string isn’t tangled inside.
For manual spool systems: Reconnect power and visually inspect the trimmer head as it rotates at idle speed. The string should extend evenly from both eyelets and spin without wobbling or rubbing against the housing.
Common Variations by Weedeater Type
Automatic Feed Weedeaters (Cartridge Style)
Newer models from Ryobi, Makita, and DeWalt often use automatic feed cartridges that advance string without manual adjustment.
Installation differences:
- Remove the cartridge by pressing release tabs and pulling downward
- Feed pre-cut string into the cartridge slot (check manual for length and gauge)
- Insert the cartridge back into the trimmer head housing until it clicks into place
- The system automatically meters out string as it wears; no manual feeding is required
Automatic cartridges simplify maintenance but typically cost more to replace than traditional spools. Check whether your model allows spool replacement or requires cartridge-only operation.
Bump-Feed Trimmer Heads
Bump-feed heads are semi-automatic and common on Echo, Stihl, and many consumer models. The mechanism advances string by bumping the head on the ground.
Key differences:
- String must be wound very tightly with consistent tension for reliable bump-feed operation
- Requires adequate string length on the spool; if undersized, the bump function won’t advance efficiently
- String ends must be properly seated in spool notches to prevent premature advancement
- Testing involves tapping the head on concrete while running; string should advance 1-2 inches per tap
If bump-feed isn’t working after correct installation, the problem is usually insufficient string on the spool or string not properly seated in the notches.
Dual-Line vs. Single-Line Heads
Most residential weedeaters use dual-line heads (two cutting strings). Some commercial or specialty models use single-line heads.
Dual-line installation: One continuous string is wound to create two cutting edges on opposite sides. This is the standard procedure described throughout this guide.
Single-line installation: Only one string is loaded, typically through a single eyelet. Consult your manual, as single-line systems vary significantly in design.
Troubleshooting Common String Replacement Issues
String Won’t Feed After Installation
Causes and solutions:
- Wrong wind direction: Inspect the spool arrows and rewind if necessary. This is the most common cause.
- String wound too loosely: Remove the spool and rewind with firm, consistent tension.
- Bump-feed string not seated in notches: Reopen the spool cover and ensure string ends are fully inserted into the rim notches.
- Automatic feed cartridge not locked: Remove and reseat the cartridge until you hear or feel a definitive click.
- Damaged spool: If the spool is cracked or the winding grooves are worn, string won’t advance properly. Replace the spool.
String Tangles or Jams During Operation
Causes and solutions:
- String wound over itself: Overlapping wraps create knots. Rewind with neat, adjacent passes.
- Wrong string gauge: Verify you’re using the correct diameter. Thinner string tangles more easily.
- Excessive free string: If more than 6 inches extends from the eyelets, it can flail and knot. Trim to 4-6 inches.
- String crossing over the eyelet edges: Ensure the string feeds straight through the eyelet hole without rubbing the rim. Reposition if necessary.
Uneven String Wear or Cutting Performance
Causes and solutions:
- String lengths unequal at eyelets: Cut both sides to identical length. Slightly unequal lengths (1/4 inch difference) are acceptable and will self-balance.
- String wound unevenly on spool: Wraps bunched on one side can cause uneven advancement. Rewind with even distribution across the spool width.
- Worn or damaged string: If only part of the string is cutting effectively, the string may have worn spots. Wind more string to replace the damaged section.
Frequently Asked Questions
Q: How often should I change my weedeater string?
A: String replacement frequency depends on usage. Light residential use might require replacement once per season, while regular use could mean replacing string every 4-8 weeks. Replace string whenever it becomes noticeably shorter, frayed, or when cutting performance declines. Keep spare string on hand to minimize downtime.
Q: Can I use string heavier than recommended by the manufacturer?
A: No. String heavier than specified creates excessive drag on the motor, increases power consumption, and can cause the trimmer to overheat or shut down. Additionally, thicker string may not wind onto the spool properly or feed through eyelets designed for the correct gauge. Always use the exact gauge specified in your manual.
Q: Why does my newly wound string keep jamming?
A: Jamming typically results from winding in the wrong direction, winding too loosely, or creating overlapping wraps. Verify the wind direction matches the arrows on your spool, wind with firm and consistent tension, and ensure each wrap sits parallel to the previous one without crossing. If the spool is damaged or warped, replace it.
Q: Is there a difference between buying string in bulk vs. pre-wound cartridges?
A: Bulk string is typically more economical if you use your trimmer regularly. Pre-wound cartridges (for automatic feed models) are more convenient since they eliminate manual winding, though they cost more per use. For manual spool systems, bulk string allows you to wind exactly what you need. Check your manual to determine whether your model supports bulk string or requires cartridges.
Key Takeaways
- Safety first: Always disconnect power before working on your trimmer.
- Know your system: Identify whether you have a manual spool, bump-feed, or automatic feed system before beginning.
- Use correct specifications: Match the string gauge and length to your exact weedeater model using the user manual.
- Wind carefully: Follow directional arrows, wind tightly with even tension, and avoid overlapping wraps.
- Test thoroughly: Verify string feeds properly and test the trimmer at idle before full-speed operation.
- Maintain proper cutting length: Trim string ends to 4-6 inches per side for optimal cutting and safety.
