Direct Answer: How to String a Weed Wacker
To string a weed wacker, first turn off the machine and disconnect the power source (unplug the cord or remove the battery). For a bump-feed head, remove the spool cap, take out the old spool, and discard any leftover line. Cut a fresh piece of trimmer line to the length recommended in your owner’s manual, fold it in half, insert the loop into the anchor slot on the spool, and wind both halves evenly in the direction shown by the arrows on the spool. Feed the two loose ends through the eyelets in the spool housing, then snap the cap back on and gently tug the line to release the correct cutting length. For a fixed-line head, remove the old line, cut a new piece to the specified length, insert it through the anchor holes, and lock it into place. Always consult your specific model’s manual because line diameter, length, and winding direction can vary by brand.
Understanding Your Trimmer Head Type
Before you pick up a spool of line, you need to know which kind of trimmer head your weed wacker uses. The two most common designs are the bump-feed head and the fixed-line head, and each one requires a slightly different restringing process.
What Is a Bump-Feed Trimmer Head?
A bump-feed head, also called a tap-feed or automatic-feed head, stores a long length of trimmer line wound around an internal spool. When the line wears down, you tap the head on the ground while the trimmer is running at full speed. That bump releases a small amount of new line from the spool, and the spinning action cuts the line to the correct length. Bump-feed heads are the most common type found on residential gas, electric, and battery-powered string trimmers.
What Is a Fixed-Line Trimmer Head?
A fixed-line head uses one or more pre-cut pieces of line that are locked into slots or holes around the head. There is no spool and no bump mechanism. When the line wears out, you remove the old piece and insert a fresh one. Fixed-line heads are often found on lightweight electric trimmers and on brushcutter attachments, and they are popular with users who want a simple, no-fuss system.
How Do I Identify Which Type of Head My Weed Wacker Has?
Look at the bottom of the trimmer head. If you see a round cap with a small knob or a textured surface in the center, you almost certainly have a bump-feed head. If the head has visible slots, notches, or holes around the perimeter with short pieces of line sticking out, you have a fixed-line head. You can also check your owner’s manual or look for the brand name printed on the head and search for the model online.
Tools and Materials You’ll Need
Restringing a weed wacker is a simple DIY job, but having the right tools and materials on hand makes it faster and safer.
What Type of Trimmer Line Should I Use?
Trimmer line comes in several diameters, usually measured in inches or millimeters. Common residential sizes are 0.065, 0.080, 0.095, and 0.105 inches. The correct diameter depends on your trimmer’s engine or motor power. A small electric trimmer typically uses 0.065 to 0.080 inch line, while a gas trimmer with a larger engine may require 0.095 inch or thicker line. Using line that is too thick can overload the motor or jam the head; using line that is too thin will break frequently and cut poorly. Check the trimmer head or the owner’s manual for the recommended diameter.
Line is also available in different shapes. Round line is the most common and works well for general trimming. Twisted or star-shaped line cuts through thick weeds more aggressively but can be harder on the motor. If you are unsure, start with a round line in the manufacturer’s recommended diameter.
Do I Need Any Special Tools?
In most cases you only need a pair of scissors or a utility knife to cut the line to length. Some trimmer heads have a locking tab or a cap that is difficult to remove by hand, so a flathead screwdriver or a pair of pliers can help. A small brush or cloth is useful for cleaning grass and debris out of the head while it is open.
What Safety Gear Should I Wear?
Wear safety glasses or goggles to protect your eyes from flying debris and from the line itself when it snaps. Heavy-duty work gloves protect your hands from sharp edges on the trimmer head and from the line, which can be stiff and abrasive. If you are working with a gas trimmer, make sure the engine is off and cool before you begin. For electric trimmers, unplug the cord or remove the battery completely.
Step-by-Step Guide for a Bump-Feed Trimmer Head
Follow these steps carefully to restring a typical bump-feed trimmer head. The exact disassembly steps vary by brand, so refer to your manual if the head does not come apart as described below.
Step 1: Turn Off the Trimmer and Disconnect Power
Place the trimmer on a flat, stable work surface. Turn the switch to the off position. If it is a corded electric model, unplug it. If it is battery-powered, remove the battery pack. If it is a gas model, turn off the engine and disconnect the spark plug wire to prevent accidental starting.
Step 2: Remove the Spool Cap
Most bump-feed heads have a cap that you can twist off by hand. Press the two tabs on the side of the head, if present, and turn the cap counterclockwise. Some caps have a small arrow or a lock icon that shows which direction to turn. If the cap is stuck, use a flathead screwdriver to gently pry it loose, or wrap a cloth around the cap and use pliers for extra grip. Be careful not to damage the plastic.
Step 3: Remove the Old Spool and Clean the Head
Lift the old spool out of the housing. Unwind any remaining line and discard it. Check the spool for cracks or wear; if it is damaged, replace it with a new spool designed for your trimmer model. Use a small brush or cloth to remove grass clippings, dirt, and debris from inside the head and from the eyelets where the line exits.
Step 4: Measure and Cut the New Line
Check the trimmer head or the owner’s manual for the recommended line length. Many heads require 15 to 25 feet of line, but some spools hold less. If you do not know the exact length, a good rule of thumb is to cut a piece that is about 15 to 20 feet long, or roughly the distance from the ground to your waist. Cut the line cleanly with scissors or a knife. Avoid using line that is longer than the spool can hold, because overfilling causes jams and poor feeding.
Step 5: Fold the Line in Half and Insert the Loop
Take the cut piece of line and fold it exactly in half so both ends are even. You should see a small loop at the midpoint. Look at the spool and find the anchor slot, which is usually a small notch or groove in the center flange. Insert the loop into the anchor slot and pull it snug so the line is held in place. Some spools have two separate anchor holes instead of a single slot; in that case, insert one end into each hole and pull the line through until both sides are even.
Step 6: Wind the Line Around the Spool
Look for the directional arrows printed on the spool or on the head housing. The arrows indicate the direction in which the line must be wound so that it feeds correctly when the head spins. Hold the loop in the anchor slot with your thumb, then wind both halves of the line around the spool in the direction shown by the arrows. Keep the line taut and wind it evenly, layer by layer, so it does not cross over itself. Do not twist the two halves together. Wind until you have about 6 to 8 inches of line left on each end.
Step 7: Secure the Loose Ends in the Notches
Most spools have small notches or slots on the outer rim that hold the loose ends in place while you install the spool. Press each loose end into one of these notches. This step prevents the line from unwinding when you put the spool back into the head.
Step 8: Feed the Line Through the Eyelets
Hold the spool with the line wound in the correct direction and lower it into the head housing. Align the loose ends with the two eyelets, which are the small holes or slots on the outside of the housing. Push each loose end through its eyelet from the inside to the outside. If the line will not go through, trim the ends at a slight angle to make a point. Pull the line through until it comes out the other side.
Step 9: Reinstall the Cap and Test the Feed
Press the spool down into the housing and make sure it clicks into place. Replace the cap and turn it clockwise until it locks. Give each loose end a firm tug to release it from the notches and pull a little extra line out of the head. Reconnect the power source or spark plug wire. Hold the trimmer away from your body and start it. Tap the head lightly on the ground to test the bump-feed mechanism. The line should advance and the cutting blade on the guard should trim it to the correct length.
Step-by-Step Guide for a Fixed-Line Trimmer Head
Fixed-line heads are simpler than bump-feed heads, but they still require care to install the line securely.
Step 1: Remove the Old Line
Turn off the trimmer and disconnect the power source. Look at the fixed-line head and find the slots or holes where the line is held. Pull the old line out by hand, or use pliers if it is jammed. If the head has a removable cover, unscrew or unclip it to access the line channels. Clean out any debris from the slots.
Step 2: Cut a New Piece of Line
Check the owner’s manual for the recommended line length and diameter. Most fixed-line heads use one piece of line that is between 10 and 18 inches long, depending on the head diameter. If you are replacing two separate pieces, cut two identical lengths. Use scissors or a knife to make a clean, straight cut.
Step 3: Insert the Line Through the Anchor Points
Look for the small holes or notches near the center of the head that hold the midpoint of the line. Insert one end of the line through the first anchor hole and push it through until the midpoint sits in the groove. Then thread each end through the corresponding exit slots on the outer edge of the head. Some heads require you to push the line through a central channel and then out through two side openings. Follow the arrows or raised guides on the head to confirm the correct path.
Step 4: Lock the Line in Place
Once both ends are through the exit slots, pull them evenly so the line is snug against the head. Some fixed-line heads have a locking collar that you twist to pinch the line. Others use a spring-loaded button or a small screw that you tighten. Make sure the line is held firmly and cannot slide out when the head spins. If the head has a cover, reinstall it and secure any clips or screws.
Step 5: Trim the Ends to the Correct Length
Use scissors to trim both ends of the line so they extend about 4 to 6 inches beyond the head, or the length recommended in your manual. If the ends are uneven, the head will vibrate and cut poorly. Start the trimmer and test it on a small patch of grass to confirm the line stays in place.
Choosing the Right Line: Diameter and Shape
Selecting the correct trimmer line is just as important as winding it properly. The table below summarizes common line sizes and their typical uses.
| Line Diameter | Typical Trimmer Type | Best Use |
|---|---|---|
| 0.065 inch | Light electric trimmers | Light grass and weeds around the yard |
| 0.080 inch | Mid-size electric and small gas trimmers | General residential trimming |
| 0.095 inch | Gas trimmers with larger engines | Thick grass, overgrown weeds |
| 0.105 inch and up | Heavy-duty gas trimmers and brushcutters | Brambles, brush, and tough vegetation |
Round line is the most versatile and forgiving choice for beginners. Twisted or serrated line cuts faster but wears out faster and can strain the motor. If your trimmer manual specifies a maximum diameter, never exceed it. Using oversized line is one of the most common causes of trimmer head failure.
Troubleshooting and Pro Tips
Even when you follow the steps exactly, you may run into problems. Here are the most common issues and how to fix them.
Why Does My Line Keep Jamming or Not Feed?
Jamming is usually caused by winding the line in the wrong direction, overfilling the spool, or crossing the line over itself. Unwind the spool and start again, making sure to follow the arrows and keep the line tight and even. Also check that the loose ends are fully seated in the eyelets and that the cap is locked on correctly. If the line still will not feed, the spool may be damaged or the spring in the bump-feed mechanism may be broken.
What Causes the Line to Break So Quickly?
Rapid line breakage is often caused by using line that is too thin for the job, hitting hard surfaces like concrete or stone, or letting the line wear down to the point where the head hits the ground. Use the recommended diameter, avoid striking curbs and sidewalks, and advance fresh line frequently. Also check the cutting blade on the guard; a dull blade can fray and snap the line.
How Can I Prevent Line from Welding Together on the Spool?
Line can fuse together when the head gets hot from prolonged use, especially with thin line or heavy loads. To reduce welding, do not overfill the spool, wind the line loosely enough to allow slight movement, and take breaks during long trimming sessions. Some users lightly coat the line with silicone spray before winding, but check your manual first because some coatings can damage plastic parts.
How Often Should I Restring My Weed Wacker?
There is no fixed schedule. Restring when the line becomes so short that the head no longer cuts effectively or when the bump-feed mechanism stops advancing new line. With normal residential use, a full spool can last several weeks. Keeping a spare spool or a roll of line on hand means you can restring in minutes whenever needed.
Can I Use Any Brand of Trimmer Line?
In most cases, yes. Trimmer line is largely interchangeable as long as the diameter matches your head and the line is designed for string trimmers. Avoid using wire, rope, or fishing line, which can shatter or cause serious injury. If your trimmer head is a proprietary design, the manual may recommend a specific brand or spool replacement.
Frequently Asked Questions
Do I need to remove the spool to restring a bump-feed trimmer head?
Yes. On nearly all bump-feed heads, you must remove the cap and lift out the spool to install new line. Some newer heads allow you to thread line through a hole without removing the spool, but that is rare. If your head has a quick-load feature, follow the instructions printed on the head or in the manual.
How much line should I put on the spool?
Use the amount recommended in your owner’s manual, which is usually between 15 and 25 feet. If you do not have the manual, wind the line until you have about 6 to 8 inches left on each end. Overfilling causes jams, and underfilling means you will have to restring sooner.
Which direction should I wind the line on the spool?
Always wind the line in the direction shown by the arrows printed on the spool or the head housing. The direction is usually the same as the rotation of the head when the trimmer is running. Winding the wrong way prevents the line from feeding and can cause the head to jam.
Why does my trimmer line come out too long after I tap the head?
If the line advances too far, the cutting blade on the guard should trim it to the correct length automatically. If it does not, the blade may be dull or missing. You can also manually trim the line with scissors. If the line keeps advancing excessively, the spool may be wound too tightly or the feed mechanism may be faulty.
Final Tips for a Smooth Restringing Experience
Restringing a weed wacker becomes much easier once you understand the mechanics of your specific head. Always work with the trimmer off and disconnected, use the correct line diameter, and follow the directional arrows on the spool. Keep the head clean, inspect the spool for wear, and replace damaged parts promptly. With these steps, you will spend less time fighting with the trimmer and more time keeping your yard neat.
