Direct Answer: How to Put String on a Weed Eater

To put string on a weed eater, first identify your trimmer head type (bump-feed or manual-feed). The universal process is to remove the spool, wind new trimmer line in the direction shown by the arrows on the spool, thread the line ends through the eyelets or exit holes, and reassemble the head. For bump-feed heads, secure the line in the spool’s notch, wind it tightly, and feed the ends out; for manual-feed or fixed-line heads, cut the line to the specified length and thread it through the holes. Always use the line gauge (diameter) listed in your owner’s manual to prevent jamming, tangling, or damage to the cutting head.

Understanding Your Weed Eater Head Type

Before you start, you need to know which kind of trimmer head you have, because the loading method is different for each. The term “weed eater” is often used generically for any string trimmer, but it can also refer to the Weed Eater brand, so check the label on your tool and its manual. The two main categories are bump-feed heads and manual-feed (fixed-line) heads.

What Is a Bump-Feed Head?

A bump-feed head, also called a tap-feed or automatic-feed head, holds a spool of line inside a covered housing. When the line gets too short, you gently tap the head on the ground while the trimmer is running, which releases a small amount of new line. The cutting blade on the guard then trims the line to the correct length. Most residential trimmers use this design, and it is the most common type you will encounter when learning how to put string on a weed eater.

What Is a Manual-Feed or Fixed-Line Head?

A manual-feed head requires you to stop the trimmer and manually pull more line out of the head when it wears down. Some manual-feed heads use a spool, while fixed-line heads have no spool at all. Instead, they use pre-cut lengths of line that you insert into holes or slots on the head. These are often found on lightweight electric trimmers and some commercial models.

Single-Line vs. Dual-Line Trimmers

Some trimmer heads use one strand of line, while others use two. A dual-line head has two exit holes (eyelets) on opposite sides of the head, and the spool is divided into two chambers so each line winds separately. A single-line head has one exit hole and one chamber. Knowing which type you have matters because you will need to cut two equal lengths of line for a dual-line spool and only one for a single-line spool.

Can You Use a Pre-Wound Replacement Spool?

Yes. Many manufacturers sell pre-wound replacement spools, which are cartridges that already have the line wound on them. These are the easiest option: you simply remove the old spool, drop in the new one, thread the line ends through the eyelets, and reassemble the head. Pre-wound spools are usually brand- and model-specific, so check the packaging or your owner’s manual to confirm compatibility. If you cannot find a pre-wound spool for your model, you can buy bulk trimmer line and wind it yourself using the steps below.

What You’ll Need: Preparation and Line Selection

Gathering the right materials before you start makes the job much easier. You will need the correct trimmer line, a pair of scissors or a utility knife, and possibly a screwdriver or a small Allen wrench to remove the spool cover, depending on your head design. Some heads have a tab or button you press to remove the cover, so no tools are required.

How to Find the Correct Line Gauge (Diameter)

The line gauge is the thickness of the line, measured in inches or millimeters. Common sizes include 0.065, 0.080, 0.095, and 0.105 inches. Using line that is too thick can jam the head or overload the motor, while line that is too thin will break easily and cut poorly. The correct gauge is printed on the spool, in the owner’s manual, or on a sticker near the trimmer head. If you have lost the manual, look up your model number online and check the manufacturer’s specifications. Do not guess: the wrong size is the most common cause of feeding problems.

How Much Line Should You Cut?

For a bump-feed spool, you typically need a single long piece of line, usually between 10 and 25 feet, depending on the spool size. For a dual-line head, you will cut two equal lengths, one for each chamber. For a fixed-line head, the manual will specify a precise length, often between 8 and 15 inches per strand. When in doubt, cut a little more than you think you need for a spool, because you can always trim the excess after winding. For fixed-line heads, follow the manual exactly, because the line must fit the head without protruding too far.

What Tools Are Needed?

In most cases, no tools are required. Many heads have a push-tab or a twist-lock cover that you can remove by hand. If your head has screws, you will need a screwdriver or Allen wrench that matches the fastener. A clean, flat work surface is helpful, and a pair of sharp scissors makes cutting the line easier than using a knife.

Step-by-Step Guide for a Bump-Feed Trimmer Head

This is the most common type of head, so follow these steps carefully. The key to success is winding the line in the correct direction, which is always indicated by arrows on the spool.

Step 1: Remove the Spool Cover and Old Spool

Turn the trimmer off and disconnect the power source. For an electric trimmer, unplug it or remove the battery; for a gas trimmer, disconnect the spark plug wire. Press the tabs on the sides of the head to release the cover, or unscrew it if your model uses a screw. Lift the cover off and remove the old spool. If there is old line left, pull it off the spool and discard it. Take a moment to clean out any grass, dirt, or debris from inside the head, because buildup can cause the line to jam later.

Step 2: Prepare the New Line

Cut a single long piece of line of the correct gauge. For a dual-line head, cut two equal lengths. Check the spool for arrows or a diagram showing the winding direction; this arrow is the direction the line must be wound so that it feeds correctly when the head spins. Winding in the wrong direction is one of the most common mistakes and will cause the line to tangle or fail to feed.

Step 3: Secure the Line in the Spool Notch

Most spools have a small notch, slot, or hole near the center on each side. Insert the middle of the line into the notch, or insert one end of the line into the anchor hole, depending on your spool design. For a dual-line spool, place the middle of the line in the center divider so that one length goes to each chamber. Hold the line in place with your thumb so it does not slip while you wind.

Step 4: Wind the Line Tightly in the Arrow Direction

Begin winding the line onto the spool in the direction of the arrow. Keep the line taut and wind it neatly, layer by layer, without crossing over itself. If you are winding a dual-line spool, wind each side separately: wind one length into its chamber, then turn the spool and wind the other length into the opposite chamber. Leave about 4 to 6 inches of line unwound at the end of each length. Do not overfill the spool; most spools have a small line guide or a set of notches that show where to stop. Overfilling causes the line to bind inside the head.

Step 5: Thread the Line Ends Through the Eyelets

Once the spool is wound, place it back into the head housing. Feed each loose end of the line through the eyelet or exit hole on the head. For a dual-line head, each end goes through its own eyelet on opposite sides. Pull the line ends until they stick out about 4 to 6 inches beyond the head. If the line will not pull through easily, check that the spool is seated correctly and that the line is not caught under the spool.

Step 6: Reassemble the Head and Test the Feed

Press the spool down into the housing until it clicks or seats firmly. Align the cover with the tabs or screw holes and press it into place until it locks. Reconnect the power source and start the trimmer. Let the head spin and check that the line is being cut to the correct length by the blade on the guard. If the line does not advance, stop the trimmer, disassemble the head, and verify the winding direction and that the line ends are properly threaded.

Loading a Manual-Feed or Fixed-Line Trimmer Head

If your trimmer does not have a bump-feed head, the loading process is different. Some manual-feed heads still use a spool, but you advance the line by hand instead of tapping the head. Others are fixed-line heads that use pre-cut pieces of line with no spool at all.

How to Load a Manual-Feed Spool Head

Remove the cover the same way you would on a bump-feed head. Take out the old spool and remove any remaining line. Wind new line onto the spool in the direction of the arrows, leaving a few inches of slack. Feed the loose end through the eyelet, then reassemble the head. To advance the line, stop the trimmer, press the spool release button if your model has one, and pull the line out manually until it reaches the desired length.

How to Thread a Fixed-Line Head

Fixed-line heads do not have a spool. Instead, they have holes or slots on the head body where you insert pre-cut lengths of line. Cut the line to the length specified in your owner’s manual. Insert one end of the line into the hole until it comes out the other side, then pull it through so an equal length protrudes from each side, if the head is designed that way. Some fixed heads require the line to be threaded through a center hole and out two side holes. Make sure the line is seated securely and that both ends are long enough to cut effectively but not so long that they hit the motor housing. Reassemble any covers and test the trimmer.

Tips and Troubleshooting

Even with the correct steps, you may run into issues. The following tips address the most common problems people face when putting string on a weed eater.

What Happens If You Wind the Line in the Wrong Direction?

If the line is wound opposite to the arrow direction, it will not feed out when the head spins. Instead, the line may unwind, tangle, or break. The head is designed so that centrifugal force pulls the line out only when it is wound in the correct direction. If your line will not advance, the first thing to check is the winding direction. Remove the spool and rewind it following the arrows.

Why Does the Line Keep Tangling or Jamming?

Tangling and jamming are usually caused by one of four problems: winding the line too loosely, overfilling the spool, using the wrong line gauge, or threading the line through the wrong eyelet. Wind the line tightly and evenly, stop at the fill line on the spool, and check your owner’s manual for the correct diameter. Also make sure each line end goes through its own eyelet and that the line is not caught between the spool and the housing.

How Do You Prevent the Line from Welding Together on the Spool?

Trimmer line can soften and fuse together when the head gets hot from prolonged use. To prevent this, avoid winding the line too tightly against itself in overlapping layers, and do not overfill the spool. Some manufacturers recommend soaking the line in water before loading, but this is not necessary for all brands, so follow the instructions in your manual. If the line welds together, remove the spool, separate the line carefully, and rewind it more loosely.

Why Does the Line Break Immediately After Loading?

Immediate breakage usually means the line is too thin for the head, the line is old and brittle, or the line is catching on a sharp edge inside the head. Check the gauge against the manual, use fresh line, and inspect the eyelets for burrs or damage. If the eyelets are worn, the line will fray and snap, and the head may need to be replaced.

Frequently Asked Questions

Do I need to remove the entire trimmer head to put on new string?

Usually not. For most bump-feed and manual-feed heads, you only need to remove the cover and the spool, not the whole head assembly. The cover is held by tabs or a screw. Only fixed-line heads may require you to access the head body directly, but even then you usually do not need to detach the head from the shaft.

Can I use any brand of trimmer line?

In most cases, yes. Trimmer line is largely interchangeable as long as the diameter (gauge) matches what your trimmer requires. However, pre-wound replacement spools are often brand- and model-specific, so check compatibility before buying. If you are winding bulk line, focus on the correct gauge rather than the brand.

How often should I replace the string on my weed eater?

There is no fixed schedule. Replace the line when it becomes too short to cut effectively, when it breaks frequently, or when it has worn down to the minimum length recommended by the manufacturer. Many people replace the line at the start of the season and then top it up as needed. If you notice the line is brittle or cracked, replace it even if it is still long enough.

What is the difference between a bump-feed head and a fixed-line head?

A bump-feed head stores a long length of line on a spool and releases more line when you tap the head on the ground while the trimmer is running. A fixed-line head uses pre-cut lengths of line that you insert directly into the head; when the line wears down, you stop the trimmer and replace the pieces. Bump-feed heads are more convenient, while fixed-line heads are simpler and lighter.