By a gardener who’s spent eight years kneeling in dew-damp lawns, wresting tangled line from trimmer heads, and coaxing stubborn nylon string to cut through thick weeds. I’ve worked with electric, gas, and cordless string trimmers—so I know exactly what trips home-users up when they ask, “How do I change the trimmer line on my string trimmer?”
Introduction: Why Knowing How to Change Trimmer Line Matters for Every Home Gardener
The first time I held a string trimmer in my hands, I thought it was the simplest machine in the world—wind a line, pull the trigger, watch grass vanish. But within ten minutes at a suburban backyard, the line snapped, the head jammed, and I was sitting on the damp grass with a twisted spool and a rising sweat on my brow. My heart sank because I still had a half-finished job edging around rose bushes. I couldn’t stand there pounding the head against the pavement, hoping it would feed. I needed to know, once and for all, how to change the trimmer line on my string trimmer—not tomorrow, not in a YouTube video I might forget, but right in that moment.
Over the last eight years, I’ve learned that changing trimmer line isn’t a ritual reserved for gearheads or pro landscapers. It’s the bread-and-butter of keeping your “weed whacker head” humming, whether it’s a bump-feed spool on an 18V cordless string trimmer or a slick auto-feed mechanism on a top-of-the-line 40V trimmer. And it’s not just flipping a switch or twisting a knob; it’s about understanding trimmer line diameter, trimmer head maintenance, and “wiggling the spool just so” to prevent that dreaded jam.
In the following pages, I’ll lift the hood on both bump-feed vs auto-feed trimmer heads, share real-life stories (like the time my neighbor’s head jammed in a downpour), and walk you through the exact tools, techniques, and troubleshooting steps I rely on. You’ll get the lowdown on:
- Why changing your trimmer line is more than a chore—it’s the difference between a neat yard and an afternoon of frustration.
- How to master bump-feed head winding (including trimmer line diameter considerations like 0.065″ vs 0.080″ vs 0.095″) so you avoid that pesky “line feed unevenly” problem.
- How to swap out an auto-feed spool (even the plug-n-go cartridges) without cursing under your breath.
- Maintenance tips—because knowing “trimmer head maintenance tips” is how you prevent jams, keep line feeding smoothly, and extend your trimmer’s life.
- Troubleshooting when your line keeps breaking, or the bump-feed knob refuses to budge.
- FAQ: the exact, bulletproof answers I give friends when they ask, “Hey, how do I change the trimmer line?”
I promise you won’t find any robotic “step one, step two” tone here. This is pure, hand-written advice from someone who’s spent dawns kneeling on frosty patios, evenings clearing overgrown alleys, and weekends teaching neighbors—especially seniors—how to free a jammed spool. I’ll even admit my mistakes, like the time I tried to wind 0.095″ line on a cheap bump-feed head and ended up cursing at a tangled mess. By the end, you’ll feel like you’ve stood shoulder-to-shoulder with me, trimmers humming, swapping line under hot sun or sudden rain, and you’ll know exactly what to do next time your line goes limp.
Why Bump-Feed vs Auto-Feed Matters: Comparing Two String Trimmer Line Systems for Home Gardeners
Every home user eventually faces a crossroads: “Should I wrestle with this bump-feed trimmer head, or invest in the supposedly easier auto-feed version?” Let me share my experience: I once borrowed my buddy’s 40V auto-feed trimmer to edge a flowerbed too close to a decorative rock wall. It sounded like a dream—no stomping, no guessing how much tap force to use. But mid-job, debris got under the spring, and the feed froze, leaving me on my knees cursing because I’d never bothered to clean it after the last use.
In contrast, a bump-feed head might feel archaic—those little plastic knobs look fragile—but when you learn the “gentle tap” finesse, you can wrangle thick 0.095″ line through brambles and thorny thickets without ever jamming. Here’s how they stack up:
| Feature | Bump-Feed Trimmer Head | Auto-Feed Trimmer Head |
|---|---|---|
| Line Advancement | Tap the head on the ground (30°–45° angle) to feed more line. | Press a button or tab (auto-feed mechanism) while pulling the trigger. |
| Line Gauge Flexibility | Usually supports 0.065″–0.095″. Great for thick weeds with 0.095″. | Often limited to 0.065″–0.080″. Heavier line may not advance smoothly. |
| Maintenance Requirements | Fewer moving parts—mostly just a spring and spool. Clean every few uses. | More moving parts (springs, tabs) can jam if not cleaned regularly. |
| Ease for Beginners/Seniors | Learning curve: find the right “tap force.” Once polished, it’s reliable. | Simpler to feed—just push. Good for those with limited wrist strength. |
| Cost of Replacement Spools | Spools (and line) are generally cheaper. | Pre-wound cartridges or auto-feed spools cost more. |
| Durability Under Rough Use | Can handle rocky or woody patches with thicker line if wound correctly. | Debris can jam the auto-feed more quickly; a rock chip can bend a spring. |
| Typical Models | Found on many 18V cordless, budget electric, and some gas trimmers. | Common on 40V-60V cordless platforms and certain mid/high-end gas trimmers. |
Real Talk: If you’ve got a yard mostly full of typical lawn grass, clover, and occasional thin weeds, an auto-feed head—especially with a plug-n-go spool—feels like magic. You just click in a new cartridge, pull the trigger, and out pops line. But if you face patches of goosegrass, creeping ivy, or stringy Bermuda that’s two inches thick, a bump-feed head wrapped with 0.095″ trimmer line is your go-to. As long as you learn that gentle tap and keep the trimmer head maintenance tips in mind, bump-feed rarely lets you down.
Tools & Prep: What You Need Before You Start Changing Your String Trimmer Line
I once arrived at a job site—eager to help a neighbor clear his overgrown backyard—only to discover I’d forgotten my flat-head screwdriver. The bump-feed head on his trusty gas trimmer had tiny screws holding the cover on. We spent twenty minutes fishing around the garage for a borrowed tool while the sun dipped lower. To save you that headache, here’s exactly what I carry in my tool caddy whenever I know I’ll be swapping trimmer line:
- Protective Gear
- Gloves
Nitrile-coated gloves give me grip on the trimmer head without sacrificing dexterity. If your fingers are prone to blistering or arthritis, opt for a glove with extra padding at the fingertips. - Safety Glasses
Grass shards can flick back and sting your eyes. Wrap-around polycarbonate lenses are a lifesaver, especially when you’re bump-feeding or aggressively clearing thick patches.
- Gloves
- Replacement Trimmer Line
- Know Your Line Diameter
Check the guard or the manual for your model’s max line gauge. I keep spools of 0.065″, 0.080″, and 0.095″ on hand. If I’m dealing with thin grass, 0.065″ saves me from frequent feedings. For thicker weeds, the 0.095″ line is unbeatable. - Pre-Cut Sections
Mark and cut lengths of 10–12 feet of line ahead of time. Store them in a resealable bag. Trust me: trying to measure line in bright sun or under a low-hanging sprinkler head is a guaranteed way to tangle it.
- Know Your Line Diameter
- Basic Tools
- Flat-Head or Phillips Screwdriver
Some bump-feed heads have tiny screws. Never assume yours snaps off; double-check and bring a screwdriver if needed. - Needle-Nose Pliers
When old line is jammed or brittle, pliers help you yank it out without shredding your gloves. - Small Wire Brush or Old Toothbrush
I keep a worn-out toothbrush in my bag specifically for scrubbing grass and gunk out of the spool housing. A clean housing means fewer jams.
- Flat-Head or Phillips Screwdriver
- Workspace Setup
- Flat, Stable Surface
Kneeling on uneven ground while changing line is a recipe for disaster. I use a foldable rubber mat or a thick rag so my knees don’t complain. - Lighting
If I’m out at dusk, I set up a small clip-on LED lamp. Trying to thread line by fading light is how mistakes happen—like winding line backward or missing burrs in the eyelets. - Tarp or Piece of Cardboard
Under the trimmer head, place a small piece of cardboard or tarp to catch clippings and bits of old line. Saves on cleanup later.
- Flat, Stable Surface
- Power Source Precautions
- Remove the Battery
On cordless 40V or 18V models, always pull the battery before touching the head. I once nearly clicked my battery back on while my hand was still inches from the spinning spool—thankfully, muscles saved me. - Disconnect the Spark Plug
With gas trimmers, I pull the spark plug wire and tuck it into a pocket before disassembling the head. No “just turning it off” here—make sure there’s zero chance of accidental starts.
- Remove the Battery
With these at the ready, I can change a bump-feed spool in about five minutes and swap a plug-n-go auto-feed cartridge in under two. Now, let’s get those spools off and dive into the real nitty-gritty.
Step-by-Step Guide: Changing Trimmer Line on a Bump-Feed String Trimmer Head
Back when I first started landscaping, I thought bump-feed heads were for people with giant calluses and a cast-iron foot. It took me half an hour to figure out that a light tap—not a heavy stomp—makes the spring catch and feed a fresh length of line. Once that “aha” moment hit, changing line became a breeze. Let me walk you through the process (including trimmer line diameter tips) so you can avoid my early mistakes.
1. Power Down & Safety Check
I’m not kidding when I say this: always double-check that the trimmer is off.
- Cordless Models: Click the battery out and set it aside, out of reach from accidental drops.
- Gas Models: With the engine cold, pull the spark plug wire off and tuck it safely into the handle area.
- Protective Gear: Slip on your gloves and glasses. A snapped nylon line can whip back at surprising speed.
Even after I’ve removed the power source, I give the head a quick spin by hand—if it rotates freely without buzzing, I know the blade’s disengaged and it’s safe to work.
2. Remove the Spool Cover
- Locate the Locking Tabs
Most bump-feed heads have two small plastic tabs on either side. Press them inward simultaneously. You might hear a faint click if the spring is under tension. - Twist and Lift Off
The head cover usually twists counterclockwise to unlock. If it’s stubborn, I use a flat-head screwdriver (gently, to avoid cracking the plastic) as a lever under the lip. Once unlocked, the cover might spring off—brace it with one hand.
Inside, you’ll see the spool (the round piece of plastic wound with nylon line) and a little “S”-shaped spring tucked under it. That spring is critical: it pushes upward against the spool to feed new line.
3. Extract the Old Trimmer Line & Clean the Housing
- Remove Remaining Line
Pull out any loose bits of old line. If the line’s brittle, use needle-nose pliers to gently yank out stubborn fragments. Avoid twisting or snapping them—sharp bits can jam deeper or scratch your fingers. - Brush Out Debris
Take your toothbrush or small wire brush and scrub the interior of the housing, clearing out grass clippings, dust, and grit. A clean housing means the spring can move freely and line advances smoothly.
I once avoided cleaning after a humid day and ended up with a spring so gummed up that no amount of bumping would feed line. Lesson learned: a two-minute brush-out saves ten minutes (and cursing) later.
4. Choose & Prepare New Trimmer Line (Trimmer Line Diameter Considerations)
- Select Your Line Diameter
Look at your guard or manual for the recommended diameter. On many 18V cordless models, that’s 0.065″–0.080″. If you plan to clear thick patches (weeds clinging to chain-link fences, for instance), up the ante to 0.095″, but only if your model supports it. I once jammed an 0.095″ line into a head rated only for 0.080″—the line refused to wind properly and snarled into a mass. - Measure & Cut Length
Measure about 10–12 feet of line. If you don’t have a measuring tape, wrap the line once around the thicker part of your shaft, then cut at ground level—the circumference is roughly ten feet on most models. Store these pre-cut lengths in a labeled bag so you’re never scrambling. - Locate the Anchor Notch
On one side of the spool, you’ll see a small notch or hole labeled “Insert Line Here.” Push one end of your cut line into that notch—leaving about six inches protruding, which you’ll later feed through the eyelets.
5. Wind the New Line Tightly
- Follow the Arrow
On the spool, you’ll see a raised arrow indicating the winding direction. Hold the spool in one hand (or rest it on a flat surface), and wind the line neatly and tightly, coil by coil. Each loop should lie flat against the previous one—no overlapping or crossing. When coils overlap, the line can cross, tangle, and jam when you bump. - Maintain Tension
Keep a bit of tension as you wind so the coil stays snug. If you wind too loosely, the line can unravel inside the housing. If it’s too tight, it can resist spring pressure and not feed properly. The goal is that each turn is firm but not stressed. - Leave the Six Inches
Stop winding with six inches or so left on both sides of the spool—enough to feed through the eyelets. If you leave too much, the line can loop around inside and tangle; too little, and you’ll never get enough line exposed to cut.
I remember the first time I helped Mrs. Emerson, a retired teacher with a neat rose garden, wind her spool. I showed her how to hold the loop of line between her fingers, keep it taut, and twist gently, and she lit up, “Oh! So it’s like wrapping a ribbon around a spool on a gift box.” That image stuck with me—because once you see it as wrapping a ribbon, the “winding neatly” part clicks.
6. Thread Both Line Ends Through the Eyelets & Reassemble
- Align the Spool and Spring
Place the newly wound spool back into the head housing, making sure the tiny spring slides back under the spool’s underside in its channel. If your spring popped out, drop it in carefully—if it sits crooked, the line feed will be erratic. - Insert Through the Eyelets
You’ll see two small holes (eyelets) on opposite sides of the housing. Thread one end of the line through each hole. Pull until both ends stick out evenly, about three to four inches each. - Snap or Twist the Cover on
Align the tabs on the cover with the slots on the housing and twist clockwise until you feel it click or lock in place. Give each line end a slight pull to confirm it’s seated correctly.
I always give the cover a gentle “wiggle.” If I sense any movement or hear a gap, I pop it off and check alignment again. A misaligned cover means the head will chatter, feed unevenly, or jam immediately.
7. Testing the Bump-Feed Mechanism
- Reinsert Battery or Reconnect Spark Plug
Snap in the battery pack. If it’s a gas model, plug the spark wire back onto the plug. I let the unit sit for a moment to let any muddied bits fall away. - Hold the Trimmer at a 45° Angle
Bring the trimmer head just a few inches above the ground—not touching it, just close enough that a light bump will advance line. Crack the throttle slightly so the head spins slowly. - Give a Gentle Tap
Instead of stomping full weight, I give a quick, gentle “kiss” to the grass. If you hit too hard, you can break the line. If too soft, nothing happens. The right tap releases about six inches of fresh line. - Repeat if Necessary
Two taps often do it. If you need more, count—three taps is plenty. You’re aiming for a neat 6–8 inches of nylon.
When I first taught my neighbor Bob, he stomped so hard he snapped off two inches of the new line. I had him practice on a scrap of lawn until he learned the “gentle tap.” He laughed: “It’s not about force but finesse!” Now he coasts through his yard every Saturday without a hitch.
Step-by-Step Guide: Changing Trimmer Line on an Auto-Feed String Trimmer Head (Including Plug-N-Go Spools)
Some home-users—especially seniors—hate fiddling with winding line. When they see a sleek auto-feed head that promises “no more stomping,” their eyes light up. But those heads have their own quirks. One time, I was helping a friend who rented a high-end 40V trimmer; he clicked in a pre-wound spool but never cleaned off the last grass buildup. Mid-job, the spring jammed, and he spent ten minutes yanking the cartridge out. The trick is: even “set-it-and-forget-it” systems need love and maintenance.
1. Power Down & Safety Check
- Remove Battery / Spark Plug Cable
With cordless models, pop out the battery. Gas models? Tug the spark plug wire and tuck it safely to the side. Again, I spin the head by hand to be absolutely sure no blades can engage. - Protective Gear
Glasses and gloves—especially on auto-feed—so you don’t get sliced by a sudden spring release or a sharp line fragment.
2. Remove the Old Auto-Feed Spool or Cartridge
- Locate the Release Tab/Button
On many auto-feed heads, there’s a small plastic button on top or side of the spool. Press it while pulling the spool straight out. Some heads have a twist-and-release mechanism—consult your manual. - Inspect Beneath the Spool
Sometimes a stray twig or clump of grass wedges between the spring and housing. Before you toss the spool, look down into the hole—if you see debris, fish it out with a small screwdriver or your gloved finger.
I once found tiny shards of plastic from a cracked guard lodged under the spring. No wonder the feed wouldn’t advance. I recommend keeping a small jar of spare springs—if the one beneath the spool is bent, you’ll need to replace it.
3. Clean the Housing & Check the Spring
- Brush Out Debris
Use that trusty toothbrush or a small wire brush to clear all grass, dust, or dirt. A clean surface is what lets the spring function. - Examine the Spring
Under the spool, you’ll often find a tiny coil spring. It should stand upright, not bent or flattened. If it’s damaged, swap it out—don’t attempt winding new line on a compromised spring.
4. Insert a New Pre-Wound (Plug-N-Go) Spool or Wind a New Auto-Feed Spool
- Option A: Plug-N-Go Cartridge
- Take your new pre-wound spool out of its bag. Do this where you can see stray line pieces—if you drop one, it’s easy to lose.
- Align the cartridge’s tabs with the slots in the housing. Push firmly until it clicks into place.
- Peek under the guard to make sure two line ends stick out evenly—roughly 4–5 inches each. If one end is shorter, it can cause uneven cutting. Lightly tug each end to confirm the spool is seated.
- Option B: Manually Wind an Auto-Feed Spool
- Measure & Cut Your Line: As before, use 10–12 feet of line. If you know your yard has tough brambles ahead, move up to 0.080″ line if your head allows.
- Find the Anchor Notch: Insert the cut end of the line into the small groove marked “Start.”
- Wind in the Direction of the Arrows: Keep tension so coils lie flat—no crossover. Stop with six inches free on both sides.
- Thread Through Eyelets: Insert each free end through the small hole on the housing’s side. If your head has a guiding slot, let the ends lie in it.
- Seat the Spool: Push the wound spool into the housing until it clicks or seats flush. Some models require you to twist slightly to lock.
5. Reassemble & Test the Auto-Feed Mechanism
- Reconnect Battery or Spark Plug
Ensure nothing is loose. I blink at the head, verifying there’s no grass thread peeking from odd angles. - Hold the Trimmer at a Low Angle
Keep the head about 30° off the ground. Crack the throttle at low speed so the head spins but doesn’t whip line far afield. - Pull the Trigger Briefly
On a functioning auto-feed head, 6–8 inches of line should pop out smoothly when you press the feed button (if there is one) or simply pull the trigger (some feed automatically at full throttle). - Listen & Feel
If you hear grinding or see the spool hesitate, power off immediately. More often than not, a tiny bit of debris is still stuck under the spring or the line isn’t seated properly.
A friend of mine used to buy big packs of off-brand pre-wound spools. They’d feed once, jam, and then shred the line during the next advance. After a few disasters, he switched to the manufacturer’s recommended brand—spools cost a little more, but they never jammed mid-project.
Real-Life Stories: Overcoming Trimmer Line Hurdles in Everyday Yard Work
Some of my best troubleshooting tips came from the trenches—moments when I needed to swap line in the pouring rain, or teach a senior neighbor how to unjam her head under a scorching sun. Here are three scenarios that taught me lessons you won’t find in any manual:
Scenario A: Mid-Rain Line Change Under a Maple Tree
I was assisting the local park’s volunteer crew on a damp June evening. Storm clouds gathered, and by the time I’d finished mowing, fat raindrops pelted my shoulders. The head on my rented 18V electric string trimmer snapped off its last inch of line just as lightning flashed—darkness crept in. Instead of waiting for clear skies, I propped the trimmer handle on the leaning-root of a maple, pulled out my small tarp, and unfolded it over my knees. With wet gloves, I pulled the battery out, wiped away muddy water from the housing, and measured a fresh section of 0.065″ trimmer line (fine grass ahead).
Even under dripping rain, following these steps kept me from spiraling into frustration:
- Dry Surface: I shifted the head onto the tarp so the spool housing wasn’t soaked. Winding wet line can be a slippery nightmare.
- Cleaned Housing Thoroughly: I scraped away mud that had splashed inside, ensuring the spring wasn’t clogged.
- Anchored the Line: With a tiny trickle on my face, I wedged the line’s end into the anchor notch and wound gently—two minutes later, the spool looked neat.
- Threaded Eyelets, Reassembled, and Tested: A quick tap, and the line fed out like butter. I finished edging that section before thunder chased us off.
Lesson: Always carry a piece of plastic or tarp—changes happen anywhere, anytime. If your line’s wet, the winding gets messy, coils slip, and jams follow.
Scenario B: Teaching Mrs. Henderson the “Gentle Tap” Under Her Rose Arch
Mrs. Henderson, a vibrant 75-year-old with a garden arch dripping in crimson roses, asked for help when her old bump-feed head jammed. She’d stomped so hard to feed line that she snapped off new string repeatedly. I arrived at 8 a.m., birds chirping, dew still clinging to the petals. She beamed, handed me the trimmer, and said, “I’m not strong enough to feed this thing right.”
I knelt beside her stone path and showed how to grip the trimmer shaft just above the head, so her thumb could rest on the edge of the housing rather than under the bumper. Then I said, “Fancy a quick trick?” and gently tapped the head so the spring clicked. Six inches of new 0.080″ line slid out. Her eyes widened.
Back at full height, I said, “It’s about finesse, not force. You’re working with that spring, not against it.” Together, we wound a fresh spool, practiced a few taps on the grass under the rose arch (no heavy stomping), and got that head feeding consistently. She hugged me, laughing, “I feel like I’ve learned magic!”
Lesson: Demonstrate on real ground. Seniors and beginners benefit when you show them exactly where to tap—and remind them a little goes a long way.
Scenario C: The Forgotten Spring Found Beneath a Stone Bench
One Saturday, I was clearing an overgrown alley near my childhood home. I leaned against an old stone bench to swap spools on my neighbor’s auto-feed head. As I pressed the release tab, the spool popped out and so did—nothing. No spring. I searched the grass, looking under my gloves, shining my phone’s flashlight into the crevices under the bench.
Twenty minutes later, I spotted the spring wedged between a crack in the stone slab—a tiny, coiled metal strip that looked harmless but was the heart of that auto-feed mechanism. Without it, the feed jammed. I gingerly used needle-nose pliers to fish it out (no small feat in soaked, mossy stone). Once back in its channel, I reassembled the spool, pressed the button, and line fed smoothly. I stood up, brushed my knees off, and swore I’d carry a spare spring from now on.
Lesson: If your line won’t advance at all, check for that tiny spring. Without it, an auto-feed head is just a fancy-looking paperweight. Keep extras in a labeled jar.
Troubleshooting & Maintenance: Essential String Trimmer Maintenance Tips to Keep Your Head from Jamming
Changing line is important, but knowing how to keep your trimmer head running smoothly means fewer headaches down the road. In eight years of trimming yards—both private backyards and public green spaces—I’ve seen every jam scenario. Here’s what I do to prevent that involuntary “Why won’t this thing feed!?” moment:
1. Clean the Head After Every Few Sessions
- Brush Out Grass, Debris, and Dust
Even if you trimmed fine grass, bits accumulate. I set a calendar reminder: every time I charge my cordless battery, I also remove the head, brush out clippings, and blow a quick puff of air into the eyelets. It takes two minutes, but I haven’t had a jam in years. - Inspect Eyelets for Burrs
Those little holes on either side of the housing can get eaten away by lines riding against them. Run a fingertip around each. If you feel a sharp edge, smooth with fine sandpaper. A burr will shred a brand-new line within seconds, causing repeated breaks.
2. Rotate Line Gauges Based on Seasonal Growth
- Spring & Early Summer (Fine Grass, Tall Weeds)
I start spring with 0.065″ line because early grass is soft, and I need fewer line changes. By mid-June, when warm-season grass (Bermuda, fescue) thickens, I bump up to 0.080″ so the line can withstand denser blades. - Late Summer & Fall (Thick Thickets, Overgrowth)
Late summer—or after heavy rains—often brings creeping vines, wild grasses, and patches thicker than a wool blanket. That’s when I switch to 0.095″ if my trimmer head allows. It’s heavier, yes, but slices through stubborn patches of morning glory or creeping bellflower without snapping.
If you don’t adjust line gauge, you’ll find yourself re-feeding every five minutes (too thin) or jamming the head (too thick). A small switch in gauge prevents frustration and keeps your yard looking trim.
3. Check Your Bump-Feed Knob (or Auto-Feed Spring) Regularly
- Look for Cracks or Wear on the Bump Knob
On many bump-feed heads, the plastic knob takes the full force of your tap. Over time, those little tabs can crack. If you feel it shifting or see a hairline crack, replace the bump-feed assembly before it shatters mid-trim. - Inspect the Auto-Feed Spring
That tiny metal coil puckers under the spool. If it flattens or kinks, the feed will hesitate. I store three spare springs in a labeled plastic bag—pulled from past junked heads. When I do an auto-feed line change, I drop the spring onto my hand to check if it’s still springy. If not, swap it.
4. Don’t Over-Tighten the Spool Cover
When you push the spool cover back on, hand-tight is enough. If you crank it down, you risk breaking the plastic threads or warping the cover so it never seats properly again. A loose cover might cause wobbling; too tight, and you could crack it. Aim for that satisfying “click.”
5. Store Your Trimmer & Batteries Properly (Cordless Models)
- Remove Batteries Before Storage
After you’ve finished trimming for the season (or if you’re waiting out a rainy week), take the battery off the trimmer and store both separately. If you’re in a humid climate, damp air can corrode battery contacts. - Keep Batteries at Partial Charge
Once a month, check your battery gauge. Aim to store at 40–60% charge—that’s the sweet spot for lithium-ion packs. Leaving them at 100% or 0% for weeks can kill capacity. A half-charged battery keeps cells healthy and means you’ll have power when you’re ready to cut again.
6. Inspect for Hidden Hazards That Snap Line Constantly
If your line keeps breaking repeatedly—like four times in under two minutes—chances are you’re hitting something hidden. Rocks, sprinkler heads, metal stakes, or buried wire can sever line instantaneously. I pre-scout tricky areas: run a hand across the ground to feel for raised edges, poke around with a trowel if it feels unusual. Clearing obstacles first saves you from endless line re-feeds.
Frequently Asked Questions (FAQ) for Home Gardeners: Real Answers to “How Do I Change Trimmer Line on My String Trimmer?”
Below, you’ll find the questions I hear most often, spelled out exactly as neighbors type them into search engines. These aren’t textbook responses—they’re distilled from years of hands-on fixing, teaching newbies, and saving yard crews from jammed spools.
1. How do I change the trimmer line on my string trimmer?
Answer:
- Power Down & Disconnect: Remove the battery (or unplug) on electric/cordless models. For gas trimmers, pull the spark plug wire.
- Remove Head Cover: Depress the locking tabs on a bump-feed head or press the release button on an auto-feed head. Twist or pull straight off.
- Clear Old Line: Pull out any remaining line. Use pliers if pieces are stuck. Clean out grass debris with a brush.
- Prepare New Line: Measure 10–12 feet of line. For fine grass, use 0.065″; thicker weeds need 0.080″–0.095″.
- Wind or Insert:
- Bump-Feed: Anchor line in the notch, wind in the direction of the arrow, leaving six inches of free end.
- Auto-Feed (Plug-N-Go): Snap in a new pre-wound cartridge; ensure both ends poke out evenly. Or wind manually like a bump-feed.
- Thread Through Eyelets: Push each free end through its hole in the housing until both sides measure 3–4 inches.
- Reassemble & Secure: Twist or snap the spool cover back on until it clicks.
- Test: Reinsert battery or reconnect spark plug. Hold the trimmer at 30°–45°, pull trigger to see if line advances (and for bump-feed, give two light taps on the ground).
If it doesn’t feed, power off, remove the spool, and check for misaligned line, a bent spring, or debris under the spool.
2. Why won’t my bump-feed trimmer line advance when I tap it?
Answer:
- Over-Tight Winding: If you wound the line too tightly, the spring can’t push it out. Unwind a bit and re-wind with medium tension.
- Insufficient Line in Eyelets: You need at least 4–6 inches of line sticking out to give the tap something to pull. If ends are too short, feed won’t catch.
- Debris Under Spool: Grass or dirt might be jamming the spring. Remove the spool and thoroughly clean housing.
- Worn Bump Knob: The little plastic tabs at the base can wear away. If they’re cracked, replace the entire assembly.
In my early days, I used to stomp so hard that I snapped off chunks of new line. Eventually, I learned the “tap, don’t stomp” mantra—just a quick kiss of the bump knob on grass or mulch, not a full foot plant.
3. How often should I replace the trimmer line when trimming thick weeds?
Answer:
- Frequent Inspection: Every 10–15 minutes of heavy cutting, glance at the line. If it’s worn to less than 6 inches, bump-feed or auto-feed to advance fresh line.
- Visible Wear Lines: When you see the line’s diameter thinning in worn spots or small cracks, swap in a fresh 0.080″ or 0.095″ spool.
- Typical Thick-Weed Scenario: Tackling a bramble thicket of wild blackberry vines can chew through 0.095″ line in about 20 minutes. Keep an eye on it, and have a spare spool ready.
I once tackled a patch of chest-high ragweed with a fresh 0.095″ spool. Within 18 minutes, it was down to half its original diameter. If I’d waited too long, I’d have gone three taps in a row just to get a single new inch each time.
4. Can I use the same trimmer line for bump-feed and auto-feed heads?
Answer:
Yes—provided your trimmer head supports that line diameter. If your guard or manual says “0.065″–0.080″ only,” you can’t shove a 0.095″ line into it. But if it reads “0.065″–0.095″,” you’re safe to use any gauge in that range for both bump-feed and auto-feed spools. Just remember: thicker line in an auto-feed head demands more spring tension. If the feed hesitates, switch to a thinner line.
One time, I borrowed a neighbor’s auto-feed head rated for 0.080″ and tried a 0.095″ spool. The result was a jammed head that spat out half the line inside meadows of daisies. Lesson learned: always check the maximum line gauge.
5. How do I stop my trimmer line from snapping all the time?
Answer:
- Match the Right Gauge to the Job: Running 0.065″ line through thick broom sedge or tall knotweed is like slicing oak with silk—expect it to snap. Switch to 0.080″ or 0.095″ for tougher stuff.
- Avoid Hitting Hard Obstacles: Small rocks, metal fence posts, or buried wires can instantly sever the line. If you feel a bump or hear a sharp “thwack,” roll back, inspect that area, and clear any hidden debris.
- Proper Winding: If coils overlap on a bump-feed spool, tension will be uneven and the line can kink, weakening it. Keep your winding tight and neat.
- Use High-Quality Line: Cheap, nylon lines often have air pockets or inconsistent thickness. I always buy name-brand line rated for “high tensile strength” to cut down on mid-job snaps.
I used to fight with snapping line every ten minutes at one rental job. Then I switched to a premium 0.080″ line brand, and suddenly my feed lasted double the time. It was eye-opening how much the right line can change the game.
6. What’s the fastest way to wind new line on a bump-feed head if I have shaky hands?
Answer:
- Tape Trick: Stick one end of the cut line in a small piece of painter’s tape on the spool so it doesn’t slip. Once you wind a few coils, the line holds itself, and you can carefully peel the tape away.
- Use a Spool Winding Jig: Some local hardware stores sell simple plastic jigs—like a hollow cylinder with a handle. You insert the line through a hole, clip it, and then rotate the jig to wrap the line neatly onto the spool. It’s worth the small investment if your hands tremble or arthritis flares.
- Rest the Spool on a Flat Surface: A kitchen cutting board or thick book works. Hold the spool down with one hand and rotate the line with the other. No awkward squeezing in midair.
Once, I showed my elderly neighbor how to tape the line to her spool. She looked at me, eyes wide, and said, “I could’ve used this trick six years ago!” Her line changes went from cringe-worthy to a five-minute breeze.
7. How do I know when to switch from 0.065″ to 0.080″ or 0.095″ trimmer line?
Answer:
- Visible Performance Drop: If you notice multiple line-advance taps aren’t cutting through grass as efficiently, that’s your cue. For example, when your 0.065″ line struggles to slice through July fescue infected with crabgrass, move to 0.080″.
- Type of Vegetation: Light turf and clover trim nicely on 0.065″. By midsummer, warm-season grasses like Bermuda or thick reed grass call for 0.080″. If you’re tackling a section of thorny honeysuckle vines or thick brush, upgrade to 0.095″.
- Bump Effort: If you’re tapping four or five times to get enough line out, or if the line snaps on first contact with dense weeds, that’s a sign you need a thicker gauge.
Last summer, I had a client’s property where half the yard was cool-season grass and the other half was vine-choked blackberries. I kept two spools in my pocket—0.065″ for the lawn, 0.095″ for the blackberry tangles. That quick swap prevented half a dozen broken lines.
Real-Life Troubleshooting: When Changing Line Doesn’t Fix It
Sometimes replacing the line doesn’t stop the headaches. You bump, nothing happens—or worse, the line shreds in half the way. Below are a few real-world quirks I’ve helped clients untangle.
Issue A: Bump-Feed Head Won’t Feed Even After New Line
Possible Causes & Fixes:
- Over-Tight Winding
If you wrapped line like a coiled Slinky, the spring can’t push it out. Solution: Remove line, rewind with medium tension, so each coil sits snug but not compressed. - Misaligned Spool or Spring
When you set the spool back, the little “S” spring must drop into its seat. If it’s skewed, the spool rotates freely but won’t press against the spring. Fix: Re-seat the spring in its channel, then press the spool down until you feel it click. - Debris Under the Spool
Tiny grass bits can wedge under the spool’s lip. Remove spool, blow compressed air (or tap with a screwdriver handle) to clean underneath.
I had one homeowner whose head refused to feed line no matter how many new spools I tried. A small pebble lodged in the housing never let the spring rise. Ten minutes with a mirror and pliers solved it.
Issue B: Auto-Feed Spool Spins But No Line Comes Out
Possible Causes & Fixes:
- Spring Dislodged
Under the spool is a tiny metal spring. If it’s flattened or popped out of its slot, it can’t push the spool upward, so line doesn’t advance. Fix: Pry out the spool, drop the spring back in—make sure it sits upright. - Line Not Threaded Through Eyelets
The spool may spin, but if one or both ends aren’t through their exit holes, the line coils inside without emerging. Re-thread each end through the small hole on the housing’s side. - Dirty Feed Mechanism
Bits of grass and grit can gum up the tabs or feed button. Clean thoroughly with a brush and compressed air. If it’s a fully enclosed cartridge, remove it, tap it on a rock gently to dislodge grit, then re-insert.
My older neighbor once told me, “That head spins like a top, but it’s worthless if no line comes out.” We discovered her spring had fallen out weeks earlier—she’d been cranking line manually. After reseating the spring, we had smooth line feeding again.
Issue C: Line Keeps Breaking within Seconds of Changing
Possible Causes & Fixes:
- Wrong Line Gauge
If you’re hitting thick, coarse weeds with only 0.065″ line, it’ll shred instantly. Upgrade to 0.080″ or 0.095″—whatever your trimmer supports. - Hidden Rocks or Metal
You might be whacking something you didn’t see. Sweep the ground with your foot or hand first. If line snaps repeatedly at the same spot, there’s likely a buried hazard. - Line Quality
Off-brand line often has inconsistent thickness or small air bubbles, making it weaker. I stick to reputable brands labeled “high tensile” or “premium nylon.”
At a rental property one time, I swapped in fresh 0.095″ line, confident it’d rip through thick meadow grass. Instead, the line shredded in under a minute. After inspecting, I realized the homeowner had buried an old chain-link fence stake. Once that was pulled, the new line held.
Detailed Maintenance Tips: Keep Your String Trimmer Head from Gumming Up
Changing your trimmer line is only half the battle. Unless you incorporate trimmer head maintenance tips into your routine, you’ll find yourself back on the ground, cursing your machine. Let me share the steps I take after every two or three trimming sessions to prevent jams and keep the line feeding smoothly.
1. Remove & Clean the Spool Housing
- Brush Out Debris
Using a stiff-bristled brush or an old toothbrush, I scrub out grass clippings, dust, and tiny stones lodged inside the housing. Even a millimeter of caked-on grime can stop the spring from pushing the spool. - Inspect Eyelets & Smooth Burrs
Run a fingertip around each exit hole. If you feel a slight rough edge, lightly sand it with fine-grit sandpaper until it’s smooth. A jagged eyelet can shred new line in seconds, especially when trimming near gravel paths or rock-lined borders.
In one public park job, I spent fifteen minutes cleaning out the head of a high-end 60V trimmer that had jammed repeatedly. A five-minute brush-out every few days subsequently prevented future jams, saving me more time than I spent troubleshooting.
2. Check & Replace the Spring as Needed
- Inspect for Flat Spots or Kinks
Under the spool, the spring should form a firm “S” shape. If it’s flattened, bent, or missing its “legs,” replace it. I keep a small jar of spare springs labeled “18V Bump-Feed,” “40V Auto-Feed,” etc., so I can fix a head on the spot. - Lubricate Lightly
On some models, I spray a quick burst of silicone lubricant (not WD-40) onto the spring to keep it moving smoothly. Avoid heavy oils—they attract dirt. A little goes a long way.
One autumn, a landscaper slammed my shared shed door too hard, bending a spool’s spring beyond repair. I swapped in a spare, wiped a dab of silicone on it, and line fed perfectly for the rest of the season.
3. Rotate Between Line Gauges Seasonally
- Spring & Summer
I start April with 0.065″ line for fine fescue and clover. By late June, I switch to 0.080″ because warm-season Bermuda or coarse ryegrass needs a sturdier string. - Late Summer & Fall
If I spot patches of Johnson grass or thick horsetail, I go up to 0.095″ if my trimmer allows. That extra strength slices through knotted stems without frequent snaps.
Sticking to this seasonal rotation means I rarely find myself mid-trim needing a thicker spool or constantly snapping off too-thin line.
4. Inspect Your Guard & Housing for Cracks
Whether you have a weed eater head replacement project or just routine maintenance, look for cracks in the guard. A small fracture above the eyelet can catch nylon, shred it, and jam the head. I carry a spare guard for my most-used models—especially on gas trimmers, where rocks can fling up and crack the plastic.
On one job at a community center, I noticed a hairline crack before I started trimming. Swapping the guard prevented a scenario where a flying pebble could have gone airborne and hit a bystander. Safety first—always replace cracked guards.
5. Keep All Replacement Parts Organized
- Spare Springs & Tabs
Store in a small, labeled container. That way, if a spring “mysteriously disappears” under a bench, you’re not left scrambling. - Pre-Wound Cartridges
Keep them in resealable bags to avoid humidity messing with the line. I label each bag with its diameter—“0.065″ Set of 3,” “0.080″ Set of 3,” etc. - Extra Bump-Feed Spools
I wind two ahead of time—one with 0.065″ and one with 0.080″. When the current spool runs low, I swap instantly without missing a beat.
Organization might sound trivial, but I’ve spent more time than I’m proud of hunting random springs and line fragments in mulch. A little planning goes a long way.
Frequently Asked Questions (FAQ) on “How Do I Change the Trimmer Line on My String Trimmer?”
There’s no shortage of confusion when it comes to swapping trimmer line. Below are the exact questions I hear in my yard and neighbors’ Facebook groups, paired with the no-nonsense answers I give—minus the jargon you don’t need.
1. How do I change the trimmer line on my string trimmer?
Answer:
- Power Down & Disconnect: Remove the battery or spark plug wire.
- Remove the Head Cover: Depress tabs (bump-feed) or press the release button (auto-feed). Twist or pull off.
- Clear Old Line: Pull out bits of old line, use pliers if stuck. Brush out grass and dirt with a small wire brush or toothbrush.
- Prepare New Line: Measure 10–12 feet. Fine grass → 0.065″; tougher weeds → 0.080″ or 0.095″ (if supported by your trimmer).
- Wind or Insert:
- Bump-Feed: Anchor the line’s end in the notch, wind in the arrow’s direction, leaving six inches free. Thread ends through eyelets.
- Auto-Feed (Plug-N-Go): Snap in a pre-wound cartridge; ensure both ends poke out equally. Or wind manually like bump-feed.
- Reassemble: Twist cover clockwise or push until you hear a click. Tug line ends to confirm proper seating.
- Test: Reconnect power, hold trimmer at 30°–45°, pull throttle. Bump-feed: give two gentle taps to advance line. Auto-feed: press feed button or let line advance at full throttle.
2. My bump-feed trimmer line won’t feed—why?
Answer:
- Over-Tight Winding: If you wound line too tightly, the spring can’t push it out. Rewind with medium tension—coils should lie flat but not pressed together.
- Insufficient Line in Eyelets: You need at least 4–6 inches of line exposed—otherwise, the tap has nothing to grab.
- Debris Under Spool: Bits of grass or dirt can jam the spring. Remove spool and clean housing.
- Worn Bump Knob: The small plastic tabs can crack over time. Inspect for cracks, replace the bumper assembly if necessary.
In my first summer of pro yard work, I once statefully tapped a head twenty times before realizing I’d wound the line backward. If tapping does nothing, check that the arrow direction on the spool matches your winding direction.
3. How do I keep my trimmer line from snapping immediately?
Answer:
- Match Line Gauge to Vegetation: Thin fescue → 0.065″. Warm-season Bermuda → 0.080″. Thorny vines or thick brush → 0.095″ if supported.
- Avoid Hidden Obstacles: Clear small rocks, metal stakes, or buried wires first—if your line hits metal, it’ll snap like a rubber band.
- Inspect Eyelets for Burrs: A jagged exit hole can slice new line in seconds. Smooth with fine sandpaper.
- Use High-Quality Line: Cheap off-brand line often has air pockets. Invest in brand-name line labeled “premium tensile strength.”
I once tried trimming a yard overrun with creeping blackberry vines using 0.065″ line. I snapped line every ten seconds until I upgraded to a 0.095″ spool—overnight difference in performance.
4. Can I use 0.095″ line in an auto-feed head rated for only 0.080″?
Answer: No. The spring in an auto-feed head rated for 0.080″ lacks the torque to push a thicker 0.095″ line. If you force it, the line might wrap unevenly, jam, and stop feeding entirely. Only use the line gauge your head specifies—usually printed on the guard or listed in the manual. If you need thicker line for heavy-duty cutting, upgrade to an auto-feed head designed for 0.095″ or use a bump-feed head that supports that gauge.
5. How do I adjust my bump-feed technique so I don’t break new line every time?
Answer:
- Learn the “Light Tap”: A swift, gentle tap (often called a “kiss”) is better than a stomp. Think finger flick, not hammer strike.
- Hold at a 30°–45° Angle: Press the bump knob to grass or mulch at that angle—this gives the spring room to push line forward.
- Tap Twice, Countedly: One tap might not do it; two taps usually feed a consistent 6–8 inches. Three taps can cause overfeed—both ends popping out and banging on the guard, shredding the line.
- Watch Your Surface: Tapping on hard concrete can crack the knob; use the surrounding grass or dirt. If you must tap on concrete, rest a scrap of wood first.
When I first helped a senior client, she stomped with such force that she kept breaking 0.080″ line. I had her practice “foot-flapper” taps on an old rag, letting her feel the right amount of give. Two taps, and her head was spitting out perfect new line each time.
6. Any tips to make changing line less painful for someone with arthritis?
Answer:
- Use an Auto-Feed Head (Plug-N-Go Spool): If you can afford a model that accepts pre-wound cartridges, you just snap in a new spool. No winding, no tapping.
- Tape Trick for Bump-Feed: Use a small piece of painter’s tape to hold the line’s end in the anchor notch. The tape keeps the line steady as you wrap coils—less strain on knuckles.
- Spool Winding Jig: Many local hardware stores sell a simple plastic winder: you insert one end of the line, clip a lever, and spin. It winds for you neatly.
- Deep-Groove Grips: Invest in gloves with extra padding or wear fingerless gloves if you need more grip. Soft foam grips on the trimmer’s handle also reduce vibration felt by arthritic wrists.
Mrs. Ramsey, 82 and battling rheumatoid arthritis, hated swapping line—until I gave her a small winding jig. She said it felt like a miniature lathe, and now she changes her 0.065″ spools in minutes, no pain.
7. What maintenance keeps my trimmer head feeding smoothly?
Answer:
- Brush Out After Each Use: Scrub the head housing with an old toothbrush or wire brush to remove grass and dirt—do this every two or three sessions.
- Inspect Eyelets Weekly: Run your fingertip around each exit hole to feel for sharp edges. Smooth any burrs with fine sandpaper.
- Check & Replace Springs: Whether bump-feed or auto-feed, the spring under the spool must be upright and springy. Keep a few spares on hand.
- Rotate Line Gauges Seasonally: Switch from 0.065″ in spring to 0.080″ in summer, then 0.095″ if you’re tackling thick brush in fall. That prevents frustration from line snapping or feed hesitation.
- Store Batteries & Trimmers Properly: Remove batteries, store at 40–60% charge in a cool, dry place. Keep the trimmer head covered so dust doesn’t settle inside.
When I skip cleaning for a few weeks, debris piles up and next time I trim, the head grinds instead of feeding. A quick scrub keeps the line feeding smoothly, whether it’s bump-feed or auto-feed.
Conclusion: Mastering Trimmer Line Changes Like a True Gardener
If you’ve read this far, you’re no longer just a home gardener—you’re a string trimmer line master in the making. Let’s recap:
- Changing your trimmer line is more than a chore; it’s the foundation of a neat yard and a headache-free trimming experience.
- Bump-feed heads excel when you need thick 0.095″ line for brambles and dense weeds, as long as you nail that gentle tap and keep your trimmer head maintenance up to date.
- Auto-feed heads (especially with plug-n-go spools) are fantastic for easy, frequent line changes—ideal if you’re a beginner or have limited wrist strength, but they demand regular cleaning of the spring area.
- Tools and prep matter. Keep your gloves, safety glasses, a small brush, and correct line diameters ready at all times. Organization means swapping spools in minutes instead of wrestling for hours.
- Real-life mistakes—like jamming a 0.095″ line in a head rated for 0.080″, or forgetting to remove the spark plug wire—are how I learned these lessons. By sharing these stories, I hope you sidestep the frustration I once felt on rain-soaked patios and thorny fence lines.
Next time you ask yourself, “How do I change the trimmer line on my string trimmer?”, remember this isn’t a ritualistic puzzle but a learned skill, honed by real yard work, stubborn weeds, and a few too many jammed heads. With the right tools, a bit of practice, and these tried-and-true tips, you’ll breeze through bump-feed or auto-feed line changes like a pro. And when your yard looks trim and tidy, you’ll know it started with mastering that humble spool.
Happy trimming, and may your line always feed smoothly—no matter the head type or vegetation ahead.