How Do You Change the String on a Weed Eater? (Step-by-Step Guide)

Direct Answer: How to Change Weed Eater String

To change the string on a weed eater, first turn the tool off and disconnect the power source: unplug an electric model, remove the battery, or disconnect the spark plug wire on a gas model and let the engine cool. For most bump-feed heads, press the tabs on the spool cap, remove the cap and the empty spool, cut a new piece of trimmer line to the length recommended in your owner’s manual, thread it through the eyelets, and wind it onto the spool in the direction shown by the arrows. Reinstall the spool and cap, then pull both string ends to release the correct amount of line before restarting. For fixed-line heads, remove the old line, cut a new pre-measured length, insert it through the head, and secure it. Always use the line diameter specified for your model to prevent jamming and damage.

Understanding the Weed Eater String Replacement Process

Changing the string on a weed eater is one of the most common maintenance tasks for anyone who maintains a lawn, but it can be confusing because there is no single universal method. The process depends on the type of trimmer head, the power source, and the specific model you own. Understanding the basics before you start will save you time and frustration.

What Does “Weed Eater” Refer To?

The term “weed eater” is often used generically to describe any string trimmer, weed trimmer, or line trimmer, even though Weed Eater is also a brand name owned by Poulan. In this guide, “weed eater” refers to the tool itself, not a specific manufacturer. Whether you own a gas-powered trimmer, a corded electric model, or a battery-powered unit, the general principles of replacing trimmer line are the same, but the details can vary.

Why There Is No Single Universal Method

There are several reasons why changing the string is not identical on every machine:

• Head type: Bump-feed heads, auto-feed heads, and fixed-line heads all work differently and require different loading procedures.
• Line diameter: Different trimmers accept different line thicknesses, usually measured in inches, and using the wrong size can cause jamming or poor cutting.
• Line length: The recommended length of line to wind onto the spool varies by model, and overfilling the spool is a common mistake.
• Power source: Gas, corded electric, and battery trimmers have different safety requirements and disassembly steps.

Main Types of Trimmer Heads

Before you begin, identify which type of head your trimmer has:

• Bump-feed head: The most common type. You tap the head on the ground while the trimmer is running to release more line. The line is wound onto a spool inside the head.
• Fixed-line head: Uses pre-cut lengths of line that are inserted through holes or slots in the head. There is no spool and no automatic feeding mechanism.
• Auto-feed head: Releases line automatically when the trimmer starts or when the line becomes short. The loading procedure is usually similar to a bump-feed head, but the release mechanism differs.

If you are unsure which type you have, check your owner’s manual or look for a bump knob on the bottom of the head. A visible bump knob usually indicates a bump-feed design.

Key Factors to Consider Before You Start

Taking a few minutes to prepare before you touch the trimmer will make the job safer and easier. The most important factors are safety, line specifications, and the differences between gas and electric models.

Safety First

Regardless of the type of weed eater you own, follow these safety steps before changing the string:

• Turn off the trimmer completely. Never attempt to change the line while the engine or motor is running.
• Disconnect the power source. For corded electric trimmers, unplug the extension cord. For battery models, remove the battery pack. For gas trimmers, disconnect the spark plug wire to prevent accidental starting.
• Let a gas engine cool down. The muffler and engine housing can be hot enough to cause burns.
• Wear gloves and eye protection. Old line can be brittle, and the spool cap may be under spring tension.
• Work on a clean, flat surface. This prevents small parts like springs and washers from rolling away.

Finding the Correct Line Diameter and Length

Using the correct trimmer line is critical. The line diameter is usually printed on the old spool, on the trimmer head, or in the owner’s manual. Common diameters include:

These are general categories, not guarantees for your specific machine. Always confirm the exact diameter in your owner’s manual. Using line that is too thick can jam the spool, strain the motor, or prevent the line from feeding. Using line that is too thin will cut poorly and break frequently.

The correct length of line to wind onto the spool also depends on the model. Most spools hold between 10 and 25 feet of line, but the exact amount is listed in the manual. When in doubt, leave a small gap between the line and the outside edge of the spool. Overfilling is a leading cause of feeding problems.

Gas vs. Electric Trimmers

The string-changing procedure itself is similar on gas and electric trimmers, but the preparation differs:

• Gas trimmers: Always disconnect the spark plug wire before working on the head. The engine must be cool. Some gas trimmers have a straight shaft with a gearbox at the head, and the head may be attached with a locking pin or wrench.
• Corded electric trimmers: Unplug the cord. There is no risk of the motor starting as long as the cord is disconnected, but be careful not to cut the cord with the trimmer line or tools.
• Battery trimmers: Remove the battery pack. This is the safest option because it completely isolates the motor from power.

In all cases, the head assembly is usually removed or opened the same way, but consult your manual for any model-specific locking mechanisms.

Step-by-Step Guide for Bump-Feed Trimmer Heads

Bump-feed heads are the most common type found on residential weed eaters. The line is stored on a spool inside the head, and tapping the head on the ground releases a small amount of line. Here is the complete process for replacing the string.

Step 1: Power Down and Prepare

Turn off the trimmer and disconnect the power source as described above. Lay the trimmer on its side on a clean work surface so you can access the head. If the head is dirty or caked with grass, wipe it off with a rag. This prevents debris from falling into the spool housing.

Step 2: Remove the Spool Cap

Look at the bottom of the trimmer head. Most bump-feed heads have a cap that is held in place by two or three tabs. Press the tabs inward with your fingers or a flat-head screwdriver, then pull the cap straight off. Some caps are threaded and must be turned counterclockwise. If the cap does not come off easily, check for a tab or arrow that indicates the release direction. Never force the cap, as you can break the plastic tabs.

Step 3: Take Out the Old Spool and Remove Old Line

Once the cap is off, the spool will either lift out freely or be held by a spring and washer. Note the order of the parts as you remove them so you can reassemble them correctly. Take a photo with your phone if helpful. Remove all old line from the spool. If the line is tangled or broken, cut it away with scissors. Inspect the spool for cracks and inspect the spring for damage. Replace any damaged parts before installing new line.

Step 4: Cut the New Line to Length

Cut a single piece of new trimmer line to the length recommended in your owner’s manual. If you do not know the length, a common starting point is about 10 to 15 feet, but check the spool’s capacity. The line should be wound evenly and should not exceed the outer rim of the spool. Using a sharp pair of scissors or a utility knife will give you a clean cut.

Step 5: Thread Through the Eyelets

Most spools have a small hole or slot, called an eyelet, on each side of the spool flange. Insert one end of the line through one eyelet and push it until it comes out the other side. The line should be centered, with equal lengths sticking out on both sides. This step is important because it anchors the line to the spool and prevents it from slipping during winding.

Step 6: Wind the Line

With the line threaded through the eyelets, hold both ends together and begin turning the spool. Look for arrows on the spool or the head that indicate the correct winding direction. Wind the line tightly and evenly, layer by layer, keeping the two halves separate. Do not cross the line over itself. Continue winding until the line is about a quarter-inch from the outer edge of the spool. Leave the two ends sticking out of the eyelets.

Step 7: Reinstall the Spool and Cap

Place the spool back into the head, aligning any tabs or notches. If there was a spring, place it back in position first. Thread the two loose line ends through the slots or notches in the outer head so they exit through the eyelets on the head. Press the spool down until it clicks into place. Replace the cap and press down until the tabs snap securely. Give the cap a gentle tug to confirm it is locked.

Step 8: Pull to Release the Correct Length

Before restarting the trimmer, pull both line ends firmly to release the line from the spool. The line should extend to the cutting length recommended in your manual, usually around 4 to 6 inches from the head. If the line does not pull out, the spool may be wound in the wrong direction or the line may be pinched. Recheck the winding direction and the alignment of the eyelets.

Step-by-Step Guide for Fixed-Line Trimmer Heads

Fixed-line heads are simpler than bump-feed heads because they do not use a spool. Instead, they hold one or two pre-cut pieces of line in place with a locking mechanism. The exact steps vary by brand, but the general process is as follows.

Step 1: Remove the Old Line

Turn off the trimmer and disconnect the power source. Examine the head to find the slots or holes where the line exits. Some fixed-line heads have a small release button or a tab that you press to release the line. Others require you to pull the line out with pliers. Remove all old line fragments from the head.

Step 2: Cut the New Line

Cut a new piece of line to the length specified in your owner’s manual. Fixed-line heads typically use shorter lengths than spool-based heads, often between 8 and 12 inches per side. Use the correct diameter for your model. A clean, angled cut makes it easier to insert the line through the head.

Step 3: Insert and Secure the Line

Insert one end of the line into the slot or hole on the head and push it through until it exits on the opposite side. Center the line so that equal lengths protrude from both sides. Some heads have a locking collar that you twist or snap closed to secure the line. Others use a small screw or clamp. Follow the arrows on the head to determine the correct position. Make sure the line is held firmly and cannot slide out.

Step 4: Test the Installation

Give both ends of the line a firm tug to confirm they are locked in place. Rotate the head by hand to make sure the line does not catch on the housing. Reconnect the power source and test the trimmer at low speed before moving to full speed. If the line whips or vibrates excessively, the lengths on each side may be uneven; trim them to match.

Auto-Feed and Other Trimmer Head Types

Some trimmers use auto-feed heads that release line automatically when the engine starts or when the line becomes too short. The loading procedure is usually identical to a bump-feed head: remove the cap, replace the spool, and wind the new line in the correct direction. The main difference is that there is no bump knob, and the line is released by centrifugal force or a mechanical sensor. After reinstalling the spool, do not pull the line out manually on some auto-feed models, because the line is supposed to feed only when the trimmer is running. Check your owner’s manual for the specific release procedure.

There are also specialty heads, such as those that accept pre-wound spools or quick-load cartridges. With these, you simply remove the old cartridge and snap in a new one, which eliminates the need to wind line by hand. Always verify that the replacement cartridge matches your trimmer model.

Troubleshooting and Final Tips

Even when you follow the steps correctly, you may run into common problems. Here is how to solve them.

Line Jams or Won’t Feed

• Check the winding direction. If the line is wound opposite to the arrows, it will not feed. Remove the spool and rewind it correctly.
• Check for crossed line. Overlapping line on the spool can lock the spool in place. Rewind the line evenly, keeping the layers flat.
• Check for overfilling. Too much line on the spool prevents it from turning. Remove a few feet of line.
• Clean the head. Dried grass and dirt can block the line exit holes. Remove the spool and clean the head with a rag or compressed air.

Line Keeps Breaking

• Use the correct diameter. Line that is too thin breaks easily on heavy weeds.
• Check for sharp edges. A damaged head or spool can fray and cut the line. Inspect the eyelets for burrs.
• Do not force the trimmer into thick growth. Let the line do the cutting and advance it as needed.

Spool Won’t Reinstall

• Align the tabs. The spool and head have alignment features that must match.
• Make sure the spring is seated. A misaligned spring will prevent the spool from sitting flush.
• Check that the line is not pinched. The line must pass through the exit slots before the spool is fully seated.

Final Tips

• Keep a spare spool. Pre-wound replacement spools are convenient and reduce downtime.
• Use quality line. Cheaper line may be brittle and break more often.
• Store the trimmer properly. Avoid leaving the head in direct sunlight, which can degrade the line.
• Check the manual. The owner’s manual is the most reliable source for line diameter, line length, and head-specific instructions. If you lost the manual, many manufacturers post PDF copies online.

Frequently Asked Questions

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

There is no fixed schedule. Replace the string when it becomes too short to cut effectively, when it breaks repeatedly, or when the spool runs out of line. Many users change the line several times per season, depending on how often they trim and the thickness of the vegetation.

Can I use any trimmer line on my weed eater?

No. You must use the line diameter recommended by the manufacturer. Using line that is too thick can jam the spool and damage the motor, while line that is too thin will cut poorly and break quickly. Check the owner’s manual or the label on the trimmer head for the correct diameter.

Why does my trimmer line keep coming out of the spool?

This usually happens when the line is wound in the wrong direction, when the spool is overfilled, or when the line was not anchored properly through the eyelets. Remove the spool, rewind the line in the direction indicated by the arrows, and make sure the line is locked in the eyelets before reinstalling.

Do I need to remove the entire trimmer head to change the string?

Usually not. On most bump-feed and auto-feed heads, you only need to remove the spool cap to access the spool. Fixed-line heads do not require head removal either. However, some models require removing the head to access a screw or locking pin, so check your owner’s manual if the cap does not come off easily.