How Do You Put Line on a Weed Eater? (Step-by-Step Guide)

Quick Answer: How to Load Trimmer Line

Understanding Your Trimmer Head Type

Before you start loading line, identify which head design your weed eater uses. Different designs require slightly different loading methods, and using the wrong technique can cause tangling or prevent line from feeding properly.

Bump-Feed Head (Most Common)

This is the standard on most residential and mid-range commercial trimmers. It features a round spool housed in a plastic head cover. The spool has two small slots or eyelets where line passes through. When you tap the head on the ground, the bump mechanism automatically feeds more line. This design is user-friendly and works well for most home users.

Fixed-Spool Head

Older or budget trimmers may have a fixed spool where line is manually wound around a stationary spool hub. These heads typically don’t feed automatically—you manually advance line as it wears. Loading takes longer but the concept is similar to bump-feed heads.

Cartridge or Pre-Wound Spools

Premium trimmers sometimes use cartridge-style heads with pre-wound line spools you simply pop in. These require no manual winding—just insert the loaded cartridge into the head and you’re ready to trim. Check your trimmer’s manual to confirm if your model uses this system.

Automatic or Semi-Automatic Heads

Some trimmers feed line automatically as you use them without bumping. These still require initial loading but may have a different threading pattern. Always consult your manual for automatic heads.

Tools and Materials You’ll Need

Gathering supplies before you start prevents mid-task frustration. You won’t need much—most of these items you likely already own.

• Replacement trimmer line: Purchase the correct gauge (typically .080″ to .095″ for residential trimmers; check your manual). Buy a pre-spooled roll or bulk line—bulk is usually more economical.
• Scissors or line cutter: A sharp pair cuts line cleanly without fraying. Some trimmers come with a line-measuring gauge on the head.
• Small flathead screwdriver: Useful for prying off the head cover or removing old line if it’s stuck.
• Safety glasses: Protects your eyes from flying debris while you work and when you test the trimmer.
• Work surface: A flat table or workbench makes handling the head easier than working on the ground.
• Your trimmer’s manual: Different brands vary in spool design and recommended line lengths (typically 15–20 feet per load). The manual clarifies your specific model.

Line Gauge Selection: Most residential gas and electric trimmers use .080″ or .095″ gauge line. Heavier .110″ line is for thicker brush and commercial use. Using the wrong gauge can cause feeding problems or reduce cutting efficiency. When in doubt, match the gauge listed in your manual or on the original spool label.

Step-by-Step: Loading Line on a Bump-Feed Head

This is the most common trimmer head type and the best starting point for learning the basics. Follow these steps carefully:

Step 1: Disconnect Power and Remove the Head

Safety first. If your trimmer is gas-powered, set the fuel valve to OFF and remove the spark plug wire. For electric trimmers, unplug from the outlet. Never work on a live trimmer—accidental activation can cause injury.

Locate the retaining nut or bolt holding the trimmer head to the shaft. This is usually accessed from underneath the head. Most trimmers have a left-hand thread, meaning you twist counterclockwise to loosen (not clockwise, which tightens). Use an adjustable wrench or the wrench provided with your trimmer. Once loose, carefully unscrew by hand and set the head assembly aside on your work surface.

Step 2: Remove the Spool and Clear Old Line

Inside the head cover is a plastic spool. Press the center button or pull the spool out (most simply pop out). Unwind any remaining old line from the spool. If line is stuck or tangled, gently work it free with a screwdriver or your fingers. Clean debris from the spool and head cavity using a damp cloth. A clean spool ensures new line feeds smoothly.

Step 3: Measure and Cut New Line

Consult your manual for the recommended line length—typically 15–20 feet, though some heavy-duty models accept up to 25 feet. Measure your line carefully using a tape measure or the pre-marked gauge on the head (many heads have measurement marks molded into them). Cut the line using sharp scissors. A clean cut prevents fraying, which can jam the spool.

Common cutting mistake: Cutting line too short (it won’t reach both slots) or too long (it won’t fit on the spool). When in doubt, cut slightly shorter—you can always add more on the next load.

Step 4: Locate the Directional Arrows on the Spool

Look at the top surface of the spool. You’ll see one or two arrows indicating the winding direction. This is critical—winding line backward causes tangling and feeding failures. The arrows point in the direction you should wind line. Most common pattern: the arrows point clockwise, meaning you wind line onto the spool by turning the spool clockwise. Some spools have separate left and right channels; if so, you’ll see two arrows (one for each side).

Step 5: Thread Line Into the Anchor Slots

Most bump-feed spools have small notches or slots near the center where the line enters. Insert approximately 6 inches of one end of your measured line into the first anchor slot. The slot should grip the line; if it doesn’t, ensure you’re inserting it fully into the slot, not just resting it on top.

Step 6: Wind Line Onto the Spool

Holding the line taut, wind the spool following the directional arrows. Wind slowly and deliberately to keep the line neat and evenly distributed across the spool. Avoid overlapping windings—each loop should lie next to the previous one without crossing. Maintain even tension throughout; too loose and the line won’t feed properly, too tight and it may bind or be difficult to reassemble.

Wind until approximately 2–3 inches of line remains unwound. This tail will be the active cutting line once you reassemble the head.

Step 7: Secure the Line and Insert Into the Second Slot

Once wound, insert the remaining tail of line into the second anchor slot near the center (the opposite slot from where you started). The slots should now hold both ends of the line in place, preventing unwinding when you reassemble the head.

Step 8: Reassemble the Head

Carefully place the spool back into the head cavity, ensuring the center post aligns with the spool’s center hole. Push down gently until the spool sits flush. You should hear or feel a slight click as it seats. Replace the head cover if your model has one (some heads don’t have a separate cover).

Step 9: Reattach the Head to the Trimmer

Align the head with the drive shaft and hand-thread the retaining nut clockwise until it’s snug. Do not over-tighten; this can crack the head or strip the threads. Hand-tight is sufficient. If your trimmer came with a wrench, you can give it a final quarter-turn with the wrench, but no more.

Step 10: Test Before Use

Before trimming grass, test the trimmer in a safe, open area away from people and obstacles. Start it and briefly engage it (for gas trimmers, give it a short burst of throttle; for electric, press the trigger briefly). Listen and watch for normal line feeding and cutting. If line doesn’t feed, stop immediately and troubleshoot (see Troubleshooting section below).

Alternative Loading Methods for Other Head Types

Fixed-Spool Heads

Fixed spools don’t pop out—the hub is permanently attached to the head. To load line, find the anchor slots (usually two small notches on the spool face). Insert one end of your measured line into the first slot, then hand-wind the entire line around the fixed hub following directional arrows, and secure the tail in the second slot. This method is more time-consuming than bump-feed loading and is becoming less common on newer trimmers.

Cartridge-Style Heads

If your trimmer uses pre-wound cartridges, loading is minimal. Simply pop out the old cartridge (usually by pressing a release button on the head) and insert a new pre-wound cartridge until it clicks into place. No measuring or winding required. Check that the cutting lines are properly extended through the head eyelets before using.

Auto-Feed Heads

Auto-feed heads automatically advance line as it wears. Loading is similar to bump-feed heads, but the spool may have additional spring mechanisms. Follow your manual precisely, as these can be finicky. Improper loading may disable the auto-feed function.

Common Mistakes to Avoid

Winding Line in the Wrong Direction

This is the #1 cause of tangling and feeding failures. Always follow the directional arrows on the spool. If you’re unsure, test by gently pulling on the wound line—it should pull smoothly from the spool. If it catches or tangles, you’ve wound it backward. Unwind completely and start over in the correct direction.

Cutting Line Too Short

If your line doesn’t reach both anchor slots, it will unwind during use. Always measure according to your manual and err on the side of cutting slightly longer rather than shorter. If you do cut too short, you can reload more line on the next attempt.

Overlapping Windings

Crossing line windings cause tangles and prevent the spool from rotating smoothly. Keep each wrap parallel to the previous one. If you make a mistake partway through, unwind back to the error and restart that section.

Winding Too Tightly

Excessive tension can make the line difficult to release and may cause it to jam. Wind with moderate, consistent pressure—firm enough that the line doesn’t slip, but loose enough to turn easily by hand.

Forgetting to Clear Old Line First

Remnants of old line left on the spool create bulk and prevent new line from fitting properly. Always remove old line completely before winding new line.

Using the Wrong Line Gauge

Installing line thicker or thinner than your trimmer’s specification can cause feeding problems and reduce cutting efficiency. Always match the gauge listed in your manual.

Troubleshooting: What to Do If Line Won’t Feed

Line Doesn’t Extend or Feed After Loading

Check the anchor slots: Ensure both ends of the line are fully seated in the anchor slots. Press firmly to ensure they’re locked in. If slots are damaged or cracked, the line will slip and won’t hold tension. Check spool installation: The spool may not be seated correctly in the head cavity. Remove the head, lift out the spool, and reseat it, ensuring the center post aligns perfectly. Verify line routing: Trace the path of both lines from the anchor slots through the head eyelets. If either line isn’t properly threaded through the eyelet, line won’t feed. Rethread if necessary.

Line Keeps Breaking After Loading

Check for sharp edges: Inspect the head eyelets (where line exits the head) for cracks, rough edges, or burrs. Sand smooth any rough spots with fine-grit sandpaper. Sharp edges nick and weaken the line. Verify line gauge: If you’re using heavier line than the trimmer is designed for, the motor may not have enough power to rotate the spool, causing excessive strain and breakage. Use the correct gauge. Inspect for debris: Clean the head cavity and eyelets thoroughly. Grass clippings or debris can catch the line and cause it to fray or break.

Line Tangles or Jams in the Head

Stop immediately to prevent motor damage. Remove the head and unwind the spool completely. Inspect for crossed windings or debris. If line is wrapped around the center post, gently work it free. Reload carefully, ensuring line winds neatly in parallel wraps. Check winding direction: If this happens repeatedly, you may be winding line backward despite thinking you’re following the arrows. Double-check the arrow direction before rewinding.

Spool Won’t Rotate Smoothly After Loading

The line may be wound too tightly or there’s excess friction. Remove the head and manually try to rotate the spool. It should turn with moderate hand pressure. If it’s locked up, remove the spool, unwind completely, and reload with less tension.

Maintenance Tips to Extend Line Life

Reload Before Line Runs Out Completely

Don’t wait until you have no line left. If you notice cutting performance declining, reload proactively. Trying to trim with minimal line puts stress on the motor and trimmer head.

Store Trimmer Line Properly

Store unused line in a cool, dry place away from direct sunlight. UV exposure and heat can degrade line, making it brittle and prone to breaking. If you have bulk line, seal it in an airtight bag or storage container.

Clean the Head Regularly

After each use, wipe down the trimmer head to remove grass buildup and debris. Use a damp cloth and let it dry completely before storing. Clean heads operate more smoothly and last longer.

Inspect Eyelets Periodically

Over time, the metal or plastic eyelets where line exits the head can wear or develop rough edges. Inspect them every few months. If you notice fraying or burring, gently smooth with fine-grit sandpaper. Damaged eyelets should be replaced to prevent premature line breakage.

Use the Correct Line Gauge for Your Tasks

Heavier line (.095″–.110″) is better for thick brush and weeds but consumes more energy. Lighter line (.060″–.080″) is easier on the motor for light residential trimming. Match line gauge to your typical trimming tasks to get the most life from each load.

Don’t Overwind the Spool

It’s tempting to cram as much line as possible onto the spool to reduce reloading frequency. Resist this urge. Overpacking prevents smooth unwinding and causes jamming. Stick to the manufacturer’s recommended line length—it’s optimized for your trimmer’s design.

Frequently Asked Questions

How often do I need to reload my weed eater?

Frequency depends on usage. Light residential use (weekly 20-minute sessions on small yards) may require reloading every 4–6 weeks. Heavy use or dense vegetation can require reloading every 1–2 weeks. You’ll notice cutting performance declining when line is nearly exhausted—that’s your signal to reload.

Can I use any trimmer line, or does it have to be the brand my trimmer manufacturer recommends?

You don’t need brand-name line. Generic aftermarket line works fine as long as it matches the gauge specified in your manual. Buying bulk line from hardware stores or online suppliers is usually cheaper than brand-specific spools. The key is matching the diameter (gauge), not the brand.

What do I do if my trimmer head won’t unscrew?

If the head is stuck, apply penetrating oil (like WD-40) around the base of the head and let it soak for 15–30 minutes. Try gently tapping the wrench with a mallet to help break the seal. If it’s still stuck, place the trimmer in a vice (pad the shaft to protect it) and use a larger wrench for better leverage. Never force it aggressively—you can crack the head or strip the threads. If still stuck after these steps, consult your manual or contact the manufacturer.

Why does my line keep coming loose from the anchor slots?

The anchor slots may be worn or damaged, or you may not be inserting the line deep enough into the slots. Try inserting the line an extra ¼ inch deeper—it should snap into place with a firm click. If slots are visibly cracked or the line consistently slips, the spool likely needs replacement. Contact the manufacturer for a replacement spool assembly.

Is it better to buy pre-cut line or bulk line?

Bulk line is more economical long-term—you pay less per foot. Pre-wound spools are convenient for immediate use but cost significantly more. If you plan to use your trimmer regularly, buy bulk line and cut it yourself. Store bulk line in an airtight container to prevent degradation.

Final Tips for Success

Loading trimmer line becomes easier with practice. Your first attempt may take 15–20 minutes; by the third or fourth time, you’ll complete it in under 10 minutes. Take your time on the first load, follow the directional arrows carefully, and don’t hesitate to unwind and restart if something feels wrong. A properly loaded spool makes trimming efficient and enjoyable. If your trimmer continues to have feeding issues after several reload attempts, the spool or head may be damaged and require replacement—a relatively inexpensive fix that often solves persistent feeding problems.