The line runs out at the worst moment, usually with one fence line left to go. Knowing how to string a weed eater turns that into a five-minute stop instead of a trip to the hardware store and a YouTube rabbit hole. The catch is that “weed eater” covers several very different trimmer heads now, and the method that works on a 15-year-old gas trimmer can be completely wrong for a new battery model.
So this guide starts with the step a lot of restringing instructions rush past: figuring out which head you have. Then it covers how much line to cut (it varies more than you’d think), the full process for each head type, and what to check when fresh line still won’t feed.
Quick Answer: Shut the trimmer off (and pull the battery or spark plug wire) before touching the head. Then match the method to the head. On a bump-feed head with a removable spool, take off the cap, anchor new line in the spool, wind it tightly in the direction of the printed arrows, and thread the ends through the eyelets. On a load-through head like the ECHO Speed-Feed or STIHL AutoCut C 26-2, you never open the head: line up the arrows, push the line straight through, center it, and twist the knob to wind it in. Use the line diameter printed on the head or in your manual, and cut only as much as your head is rated to hold.
Which Weed Eater Head Do You Have?
Look at the bottom of the trimmer head before you buy line or cut anything. Most home and pro trimmers use one of these four designs.
| Head Type | How to Recognize It | How You Load It | Examples |
|---|---|---|---|
| Bump-feed, removable spool | Cap with release tabs or a screw-off knob; spool lifts out | Take the head apart, wind the spool by hand | Most older gas trimmers, many stock heads |
| Load-through (“speed” loading) | Arrows or an alignment mark on the knob; eyelets you can see straight through | Push line through the head and twist to wind, no disassembly | ECHO Speed-Feed, STIHL AutoCut C 26-2 EasySpool, RYOBI Reel-Easy |
| Auto-feed spool | Small single-line spool, usually on light battery or corded trimmers | Replace or rewind the spool; line advances on its own | Many entry-level battery trimmers |
| Fixed-line | Short pre-cut pieces clip into slots, no spool at all | Push new pieces into the slots | STIHL FixCut and similar brushcutter heads |
The quick tell for a load-through head is a set of loading arrows or an alignment mark on the knob. If yours has them, don’t open the head. Plenty of people end up prying at a cap that was never meant to come off.
If you’re new to the tool itself, how to use a weed eater the right way covers handling and cutting technique before you get to the line.
How Much Trimmer Line Should You Cut?
Most guides give one number, usually 20 to 25 feet. That number is fine for some heads and flatly too long for others, and overfilling is one of the most common reasons a freshly strung head jams. Here’s what the manufacturers themselves say for three popular heads:
| Trimmer Head | Maximum Line Length | Recommended Diameter |
|---|---|---|
| ECHO Speed-Feed | 15 to 20 feet, per ECHO’s reload instructions | .095 inch works best in many Speed-Feed heads |
| STIHL AutoCut C 26-2 (EasySpool) | About 26 feet (8.0 m spec capacity) | .095 inch standard, .105 inch optional |
| RYOBI speed-winder heads (several 18V and 36V models) | About 10.5 feet (3.2 m), up to 1.6 m per side | Per the model’s manual |
That’s a spread of more than 15 feet between heads that all get called “weed eaters.” For anything not on this table, the spool label or the head’s instruction card is the authority. STIHL’s own guidance is blunt about this: not all STIHL line fits every STIHL head, so check the head’s card for both diameter and length.
If you have no manual and no label, measure the old line coming off the spool and cut the new piece to the same length. It’s low-tech, and it works.
How to String a Bump-Feed Weed Eater With a Removable Spool
This is the classic method, and it still applies to a huge share of gas trimmers and plenty of battery ones. You’ll need the right diameter line, scissors or snips, and gloves.
1. Shut it off completely. Turn off the engine and let it stop, or remove the battery. The LSU AgCenter warns that the centrifugal clutch that’s supposed to stop the head at idle is not something to trust with your fingers near it; kill the engine before servicing the head. Cornell University’s safety guidance for its grounds crews says the same for battery units: turn the machine off and remove the battery before installing string. On a gas unit, pulling the spark plug wire is cheap insurance.
2. Remove the cap. Squeeze the tabs on the sides of the cap, or unscrew the bump knob, depending on the design. Some caps are stubborn after a season of grass juice and dirt. A firm wiggle usually frees them.
3. Lift out the spool and note which way it faces. Take a phone photo before you pull it. Look for the arrows molded into the spool, since they tell you the winding direction.
4. Clear the old line and clean the housing. Pull off every scrap of old line. Knock out packed grass and dirt from inside the head while it’s open, because buildup keeps the spool from turning freely later.
5. Cut the new line. Use the length on the spool label or in your manual. Snip the end at an angle so it threads through anchor holes more easily.
6. Anchor the line. Push the end into the small hole or notch at the spool’s hub until it seats. For a spool with two separate channels, see the two-hole section below.
7. Wind tight and even, following the arrows. Lay each wrap next to the last one, filling the channel from side to side before starting the next layer. Crossed or loose wraps are the single biggest cause of line that won’t feed. The LSU AgCenter’s guidance is direct: wind it the wrong way and it won’t feed properly. Stop a little short of the spool’s rim.
8. Park the ends. Leave about 6 inches free on each end and press them into the retaining notches on the spool’s edge so nothing unravels while you reassemble.
9. Reassemble. Feed each end out through its eyelet, set the spool back in the housing, and snap or screw the cap on. Tug each line end; it should hold, then pull free when you press the bump knob.
10. Test before trimming. With the unit still off, bump the head on a hard surface and pull. If the line doesn’t advance, the spool is seated wrong or wound backward. Better to find out now than at the far end of the yard.
How to String a Weed Eater With Two Holes
A two-hole (dual-line) head throws two cutting lines instead of one, and it’s where most restringing frustration comes from. Before you cut anything, check how the spool is built, because there are two versions.
One center anchor. Cut a single piece of line to the full recommended length, fold it at the exact midpoint, and hook the fold into the anchor. You now have two equal tails. Wind both at the same time, in the direction of the arrows, keeping each tail in its own channel.
Two anchor holes with a divider. Cut two pieces of equal length. Anchor one in each side and wind them one at a time, each in its own section. The divider exists to keep them apart; never let a wrap jump over it.
On reassembly, each tail exits through its own eyelet. If the housing numbers or color-codes the eyelets, match them. When one line crosses over the other inside the head, the feed locks up, and the fix is starting over, so take the extra ten seconds here.
How to Load a Speed-Feed or EasySpool Head Without Taking It Apart
Load-through heads are the reason restringing has gotten much easier on newer trimmers, and they’re also the reason so many older guides now give wrong instructions. There’s no cap to remove and no spool to wind by hand. ECHO says its Speed-Feed can be reloaded in under 60 seconds once you’ve done it a few times, and RYOBI makes the same 60-second claim for its Reel-Easy+ head.
The process is nearly identical across brands:
- Power off. Remove the battery or stop the engine. ECHO also flags that the gearbox can be hot and the line-cutting knife on the shield is sharp, so keep your hands clear of both.
- Line up the arrows. Hold the head body still and turn the knob or top plate until the loading arrows line up with the eyelets. On ECHO heads, you rotate the top plate clockwise to find the alignment. On RYOBI speed-winder heads, you turn the bump knob until the line indicator meets the arrows on the outer spool.
- Push the line through. Cut your line (15 to 20 feet maximum on an ECHO Speed-Feed), straighten out any curl at the tip, and push it into one eyelet until it comes out the other side.
- Center it. Pull until both sides are even.
- Twist to wind. Hold the head and turn the knob or top plate in the marked direction. ECHO’s instructions have you stop when about 5 inches remain on each side; RYOBI’s call for roughly 12 cm, which is close to the same.
- Tug-test. Pull both ends at once. They should hold firmly.
If the line refuses to go through, the arrows almost always aren’t fully aligned. Rotate a hair in either direction and try again. A blunt or bent line tip causes the same problem, so recut it at an angle.
Stihl, ECHO, and RYOBI: What’s Different
STIHL. STIHL’s current heads include the AutoCut, the AutoCut C (EasySpool), the FixCut, and the TrimCut, and they load differently. The AutoCut C 26-2 EasySpool fits a long list of STIHL gas and battery trimmers and loads through the head with no disassembly; its spool carries arrows showing which way to turn. The FixCut uses short pre-cut pieces instead of a spool. So the answer to “how to string a Stihl weed eater” depends on which of these is on your machine. The head’s model name is molded or printed on it.
ECHO. ECHO’s Speed-Feed head is sold as a universal fit, and ECHO says it works with most gas or battery-powered trimmers, curved or straight shaft, so you’ll find it on plenty of non-ECHO machines too. ECHO lists three common mistakes: overfilling the head, using the wrong line type or diameter, and forgetting to align the loading arrows before feeding line.
RYOBI. Many RYOBI trimmers use a Reel-Easy bump head with a speed winder, which loads through the head. RYOBI’s own instructions cap the line at about 10.5 feet on the models its support page covers, far less than a STIHL AutoCut C holds. Lighter RYOBI models may use an auto-feed spool instead, so check which head yours has.
Choosing the Right Trimmer Line
Diameter comes first, and it isn’t a judgment call. Your manual or the head itself lists what fits. Line that’s too thick strains the motor and may not pass through the eyelets; line that’s too thin snaps constantly in heavy growth.
| Line Diameter | Typical Use | Typical Equipment |
|---|---|---|
| .065 inch | Light trimming around beds | Corded electric and small battery trimmers |
| .080 inch | Regular residential trimming | Many battery and light gas trimmers |
| .095 inch | Thicker weeds, frequent use | Most mid-size gas and higher-voltage battery trimmers |
| .105 inch | Heavy weeds, light brush | Professional-grade gas trimmers |
| .130 inch | Commercial brush clearing | High-output commercial trimmers |
Shape matters less than people think, but it isn’t nothing. According to the LSU AgCenter, round line is more abrasion-resistant and wears longer, while square and X-shaped profiles cut tough weeds more aggressively. If most of your trimming happens along a driveway or sidewalk, where concrete chews through line fast, round line holds up better. That’s also where edging technique makes a difference, and getting a clean edge on your lawn covers the angle and depth that keep line from grinding against the pavement.
One more money point from LSU: a pre-wound replacement head costs far more than rewinding your existing head with bulk line. Keep one spare pre-wound spool for emergencies if you like, but a bulk roll pays for itself quickly.
Why Your New Line Won’t Feed (and How to Fix It)
Freshly strung and still not working? Work through these in order. Nearly every case is one of them.
The line is wound backward. Easy to do when the arrows are worn or caked with dirt. Open it up, clean off the spool face, check the arrows, and rewind.
The wraps are crossed or loose. Crossed wraps bind against each other and stop the spool from paying out. Rewind with each wrap lying flat beside the last.
The spool is overfilled. ECHO lists overfilling as a top cause of jams. If the line sits above the rim, the cap presses on it. Cut some off.
The diameter is wrong. Line that’s even slightly too thick for the eyelets binds. Check the head’s label against the package.
The head is packed with debris. ECHO recommends periodically taking the head apart and cleaning out grass and dirt with water or light compressed air. Old buildup keeps the spool from turning when you bump.
The line is old and brittle. If it snaps every few feet, the line itself may have dried out. ECHO advises storing trimmer line in a cool, dry place to keep it from turning brittle, which rules out the top shelf of a hot garage.
Your technique is breaking it. Slamming the line into fences, rocks, and siding shreds even good line. How to weed whack your lawn covers the head angle and distance that make each fill last longer.
Should You Soak Trimmer Line in Water?
Soaking is one of the most repeated trimmer tips online, and there’s real chemistry behind it. Trimmer line is nylon, and nylon absorbs water. According to The Madison Group, a plastics engineering firm, absorbed moisture acts as a plasticizer in nylon: stiffness and strength drop, but impact resistance goes up. For trimmer line, which spends its life getting whipped into things, tougher and more flexible is the trade you want.
So soaking can help line that’s dried out, especially a roll that sat through a hot summer in a garage or shed. People who swear by it usually submerge the coil overnight and let the surface dry before loading. Two limits worth knowing: no soak repairs line that’s already cracked or splintered, and ECHO’s own advice is to store line somewhere cool and dry. Treat soaking as a rescue for neglected line, not a substitute for keeping the roll out of the heat.
When It Makes More Sense to Hand It Off
Restringing is a skill worth having, but it’s also one more chore stacked on mowing, edging, and cleanup every week of the season. Before your next roll of line, it’s worth putting what lawn mowing service typically costs next to what you spend on line, fuel or batteries, and your Saturdays.
When you’d rather skip the trimmer entirely, LawnGuru connects you with local lawn care pros who mow and trim on a regular schedule, with booking and payment handled online.
Frequently Asked Questions
Can you use any string in a weed eater?
No. Use purpose-made nylon trimmer line in the diameter your head is rated for. Fishing line isn’t built for the job, and wire or cable turns the trimmer into a real hazard. Brand matters less than diameter; STIHL notes that even some of its own line won’t fit every STIHL head, so the head’s instruction card is the final word.
How long should the line be for a weed eater with two holes?
It depends entirely on the head. An ECHO Speed-Feed takes 15 to 20 feet at most, a STIHL AutoCut C 26-2 is rated for about 26 feet, and some RYOBI speed-winder heads top out around 10.5 feet. For a traditional two-channel spool, use the length on the spool label and split it evenly between the two sides.
Which way do you wind weed eater string?
In the direction of the arrows printed or molded on the spool or knob. If there are no arrows, match the direction the old line was wound, or check the manual. Winding the wrong way is the most common reason new line won’t feed.
What does “bump feed” mean?
A bump-feed head releases more line when you tap the bottom of the spinning head against the ground. Each tap lets the spool turn slightly and pays out a short length of line, and a blade on the guard trims it to the right length.
Do I have to take the head apart to restring it?
Only on traditional bump heads with a removable spool. Load-through heads like the ECHO Speed-Feed, STIHL AutoCut C 26-2 EasySpool, and RYOBI Reel-Easy are designed to be reloaded without opening them. Look for loading arrows on the knob.
How often will I need to restring?
That depends on how much you trim and what you’re cutting. ECHO notes that heavy trimming can require reloading several times a week. Lighter use stretches a fill much further, and good technique plus properly stored line stretches it further still. Restring when bumping the head no longer pays out line, or when what’s left is too short to reach past the guard.
