Quick Answer: How to Load String Trimmer Line
To load a string trimmer, identify your trimmer type and head design (bump-feed, fixed-line, or auto-feed). Remove the trimmer head cover by twisting counterclockwise or pressing release tabs, then access the spool. Thread 15–20 feet of trimmer line into the spool slots, wind it tightly following the directional arrows, and secure the line ends in the notches. Reassemble the head, insert the line through the eyelets, and trim any excess. Always disconnect power before loading line on electric or battery models.
Types of String Trimmers and Head Designs
Understanding your trimmer type and head design is essential because loading methods vary significantly.
Trimmer Types by Power Source
- Electric Corded Trimmers: Lightweight, low-maintenance, and quieter. Require a nearby power outlet and extension cord. Always disconnect power before loading line.
- Battery-Powered Trimmers: Cordless convenience with moderate runtime (typically 20–60 minutes). Remove or power off the battery before accessing the trimmer head.
- Gas-Powered Trimmers: Most powerful option for thick vegetation and large areas. Require fuel maintenance and produce more noise. Allow the engine to cool before loading line.
Trimmer Head Designs
- Bump-Feed Head (Most Common): Line advances automatically when you tap the head against the ground. Simplest to load and maintain. Ideal for residential use.
- Fixed-Line or Manual-Feed Head: Line does not advance automatically. You manually feed line by accessing the spool or using a release button. Common in commercial models.
- Auto-Feed Head: Line advances automatically as it wears without manual intervention. More convenient but slightly more expensive to replace.
- Dual-Line Head: Two lengths of line cut simultaneously, providing wider coverage. Loading requires threading two separate lines.
How to Identify Your Trimmer
Check your trimmer’s manual or look for identifying markers on the head. Most bump-feed heads have a large round spool visible at the bottom and a rotating bump knob. Fixed-line heads typically have line already threaded and secured with no visible spool mechanism. Look for directional arrows molded into the spool or head cover—these indicate winding direction and are crucial for proper line feeding.
Tools and Materials You’ll Need
- Replacement trimmer line (correct diameter for your model, typically 0.065–0.095 inches for residential trimmers)
- Screwdriver or socket wrench (if your trimmer head requires tools; many bump-feed heads need only hand-twisting)
- Small flathead screwdriver (to help pry open some head covers)
- Safety glasses (optional but recommended)
- Work gloves (to protect hands from sharp line and edges)
Choosing the Right Trimmer Line
Consult your trimmer’s manual or the head cover for the correct line diameter and length. Most residential electric and battery trimmers use 0.065-inch or 0.080-inch diameter line. Gas-powered trimmers often require 0.095-inch or thicker line. Purchase line in bulk spools (typically 50–100 feet) rather than pre-wound spools to save money. Common line materials include nylon, which is suitable for most residential applications.
How to Load a Bump-Feed Trimmer Head (Most Common)
Bump-feed heads are found on most electric and battery-powered residential trimmers. Follow these steps for successful loading.
Step 1: Disconnect Power and Remove the Head Cover
For electric trimmers, unplug the cord from the outlet. For battery models, remove or power off the battery. Allow gas-powered trimmers to cool for at least 5 minutes. Locate the trimmer head cover (the round plastic cap on the bottom of the trimmer head). Most covers twist counterclockwise to remove, though some have release tabs that require pressing or twisting. Gently remove the cover and set aside any washers or springs—you’ll need to reinstall these in the correct order.
Step 2: Remove the Spool
The spool is the central rotating mechanism that holds the trimmer line. Most spools pull straight down and out; some are held with a center bolt or clip. If stuck, try gently twisting the spool counterclockwise while pulling. Once removed, inspect the spool for cracks or worn grooves—if damaged, replace the entire spool rather than attempting to reload a compromised one.
Step 3: Prepare the Trimmer Line
Cut a length of trimmer line approximately 15–20 feet long. Inspect both ends and trim them square if frayed. Some spools have a small hook or slot for anchoring the line’s starting end; identify this before winding. Most spools have two opposing slots or notches where you’ll insert the line.
Step 4: Wind the Line Onto the Spool
Insert the line into the first slot on the spool. Look for an arrow molded into the spool indicating the correct winding direction—this is critical. Wind the line tightly and evenly around the spool in the direction of the arrow, keeping tension as you wrap to prevent loose coils that cause tangling. Leave approximately 6 inches of line free at the end. Once you’ve wound enough line (typically filling the spool completely), insert the free end into the second slot or notch to secure it. Some spools have a dedicated notch for holding the line end; others expect you to hold tension while reassembling.
Step 5: Reassemble the Trimmer Head
Carefully push the loaded spool back into the trimmer head. Some models have tabs or guides that must align correctly—consult your manual if uncertain. Reinstall any washers or springs in the exact order they were removed. Reattach the head cover by twisting clockwise until snug. Do not over-tighten, as this can damage the cover or spool mechanism.
Step 6: Feed the Line Through the Eyelets
On most bump-feed models, line emerges from two small openings (eyelets) on the trim guard. Pull gently on both line ends to draw them through these eyelets until approximately 3–4 inches of line extends from each eyelet. Trim the excess line flush with or slightly longer than the trim guard edge using scissors or a utility knife. Uneven line lengths may cause vibration during operation.
Step 7: Test the Feed Mechanism
Reconnect power (for electric models, plug in; for battery models, reinsert the battery). Gently tap the trimmer head against a paved surface or your foot while holding the trimmer steady. This should feed additional line through the eyelets if the bump-feed mechanism functions correctly. If line does not feed, verify that the spool is seated properly and the eyelets are clear of debris.
How to Load a Fixed-Line or Dual-Line Trimmer Head
Fixed-line heads do not have a rotating spool. Instead, trimmer line is permanently threaded through the head and secured with eyelets or guides. These are common on commercial trimmers and some residential models.
Loading Fixed-Line Heads
- Locate the eyelet holes on the trim guard where line enters and exits.
- If replacing line, remove the old line by unthreading it from the eyelets and unscrewing or unclipping the anchor points inside the head.
- Insert the new line through the eyelet openings, threading one continuous length through both eyelets or two separate lengths if the model uses dual-line.
- Secure each line end inside the head by wrapping around the anchor points or inserting into designated slots. Some models require tightening a center bolt or cap to hold the line in place.
- Extend line approximately 3–4 inches from each eyelet and trim excess.
Loading Dual-Line Heads
Dual-line heads require two separate lengths of trimmer line. Follow the same process as fixed-line heads but thread two line lengths simultaneously, one through each eyelet guide. Ensure both lines are the same length for balanced cutting. Some dual-line models feature a center slot where both lines are anchored together; others have separate anchor points.
How to Load a Gas-Powered String Trimmer
Gas trimmers typically use the same bump-feed or fixed-line head designs as electric models, so the basic loading process is identical. However, gas trimmers have a few specific considerations.
Safety and Preparation
- Allow the engine to cool completely—at least 5 minutes after the last use—before accessing the trimmer head.
- Ensure the fuel valve is off if your model has one.
- Wear work gloves, as gas engines and exhaust components remain hot.
Line Specifications
Gas-powered trimmers typically require thicker trimmer line (0.095 inches or larger) to handle denser vegetation and higher cutting speeds. Check your manual for the exact diameter—using line that is too thin may result in breakage or poor cutting performance.
Loading Process
Follow the same steps as electric or battery bump-feed models: disconnect the fuel supply, remove the head cover, access the spool, wind the line with proper tension following directional arrows, and reassemble. The primary difference is the thicker line, which requires slightly more tension when winding to prevent slack coils that cause tangling.
Common Mistakes to Avoid
- Winding in the Wrong Direction: The directional arrow on the spool is non-negotiable. Winding backward prevents the line from feeding correctly and causes tangling. Always verify the arrow before beginning.
- Over-Filling the Spool: Packing too much line onto the spool causes the head cover to sit unevenly or prevents the spool from rotating freely. Wind until the spool is full but not bursting.
- Loose, Uneven Winding: Slack line tangles instantly during operation. Maintain consistent tension throughout winding to create tight, even coils.
- Leaving Line Too Long at the Eyelets: Excess line causes vibration, reduces cutting efficiency, and can wrap around objects. Trim line to 3–4 inches from the eyelet edge.
- Forgetting to Disconnect Power: Never work on the trimmer head while the device is plugged in or the battery is inserted. This risks accidental activation.
- Ignoring the Manual: Trimmer designs vary. Always consult your specific model’s manual for exact procedures, line specifications, and any model-specific quirks.
Troubleshooting: Line Won’t Feed or Keeps Tangling
Line Won’t Feed After Loading
- Spool not seated properly: Remove the head cover and verify the spool sits flush and rotates freely without wobbling. Reinstall if needed.
- Eyelets clogged with debris: Clear the eyelet openings with a small tool or compressed air. Dried grass or dirt blocks line advancement.
- Line not routed through eyelets: Ensure both line ends emerge from the correct eyelets and extend 3–4 inches. Re-thread if necessary.
- Bump mechanism failure: Tap the head firmly against a hard surface while holding the trimmer steady. If line still does not feed, the bump mechanism may be damaged and require professional repair.
Line Keeps Tangling
- Wound in wrong direction: Remove the spool and rewind following the directional arrow exactly.
- Line wound too loosely: Remove and rewind with firm, consistent tension to prevent slack coils.
- Wrong line diameter: Verify you are using the correct line diameter for your trimmer. Line that is too thin or thick feeds poorly.
- Damaged spool or eyelets: Inspect for cracks, worn grooves, or rough edges that catch line. Replace the spool or head if damaged.
When to Replace the Entire Spool
If the spool is cracked, has deeply worn winding grooves, or the feed mechanism is broken, replacement is more cost-effective than repeated reloading. Replacement spools are relatively inexpensive (typically $10–$25) and come pre-wound with line, ready to install.
Safety Tips for Loading and Using String Trimmers
- Always disconnect power or remove the battery before accessing the trimmer head. This prevents accidental activation.
- Allow gas engines to cool. Exhaust components and engine surfaces remain extremely hot after operation.
- Wear safety glasses when loading line. Trimmer line can snap suddenly and recoil if under tension.
- Wear work gloves. Line edges are sharp, and spool mechanisms can pinch skin.
- Never operate a trimmer with damaged or improperly loaded line. Tangled or broken line reduces cutting efficiency and increases the risk of thrown debris.
- Keep bystanders away during operation. String trimmers throw debris at high speed. Maintain at least 50 feet of clearance.
- Wear appropriate personal protective equipment during operation: Safety glasses, long pants, closed-toe shoes, and hearing protection (especially for gas models).
Frequently Asked Questions
How Often Should I Replace or Reload Trimmer Line?
Most residential users reload or replace their trimmer line every 4–8 weeks during active trimming season, depending on usage frequency and vegetation density. If you trim weekly, you may need to reload monthly. Keep spare pre-wound spools or bulk line on hand so you are never caught without backup.
Can I Use Any Trimmer Line Diameter?
No. Using the wrong line diameter causes poor cutting performance and potential damage to the feed mechanism. Always consult your manual for the exact specification. Electric trimmers typically use 0.065–0.080 inches, while gas trimmers require 0.095 inches or thicker. Using line that is too thin breaks easily; line that is too thick may not feed or excessive strain may damage the spool motor.
What Should I Do if the Trimmer Head Keeps Jamming?
Jams usually result from loose winding, debris in the spool, or a damaged feed mechanism. First, disconnect power and remove the head cover. Inspect for tangled line or debris and carefully remove it. Check that the spool rotates freely and sits properly. Rewind the line with firm tension. If jams persist, the spool or bump mechanism may be damaged and require replacement or professional service.
Is It Normal for Trimmer Line to Keep Breaking?
Frequent line breakage often indicates you are winding the line too loosely, using the wrong diameter, or hitting hard objects like rocks or concrete. Ensure line is wound tightly and evenly, verify the correct diameter for your model, and clear the work area of debris before trimming. If breakage continues despite correct loading, the spool or eyelets may be damaged and need replacement.
