How to Put String on My Weed Eater? Complete Step-by-Step Guide

Introduction

If you’ve ever been mid-yard work when your weed eater sputters and stops because the cutting string is worn down or broken, you’ve probably wondered, How to Put String on My Weed Eater? This is one of the most common maintenance tasks for gas, electric, and battery-powered trimmers, and it’s a simple, cost-effective skill that can save you $50 or more on a replacement tool, plus hours of trip to the hardware store. Many homeowners assume that a broken or worn-out string means they need to buy a new weed eater entirely, but that’s rarely the case. Replacing the string takes just 5 to 10 minutes with basic tools, and once you learn the process for your specific model, you’ll be able to do it quickly every time your trimmer line wears down. This complete guide covers every type of common weed eater feed system, step-by-step instructions, safety tips, common mistakes to avoid, and answers to frequently asked questions, so you can get your trimmer back up and running in no time.

• Introduction
• Understanding Your Weed Eater’s String System
• Safety Precautions Before You Start
• Tools and Materials Required
• Step-by-Step: Bump-Feed Weed Eater
• Step-by-Step: Fixed-Line Weed Eater
• Step-by-Step: Dual-Line Weed Eater
• Tips for Extending String Life and Performance
• Common Mistakes to Avoid
• Feed System Comparison Table
• Frequently Asked Questions
• Conclusion

Understanding Your Weed Eater’s String System

Before you learn how to put string on your weed eater, it’s helpful to understand how the string system works, and what type of feed mechanism your model uses. All weed eaters rely on a rotating length of plastic string to cut through grass, weeds, and light brush. Over time, the string wears down from contact with hard surfaces, dense vegetation, and the friction of spinning at high speeds. When the string is worn down to less than 2 inches, or breaks completely, you’ll need to replace it to keep your trimmer working effectively.

Types of String Feed Mechanisms

There are three main types of string feed systems used in modern weed eaters, and the process for replacing the string varies slightly depending on which type you have:

• Bump-feed: This is the most common feed type for residential weed eaters. The string is stored on a spool inside the trimmer head, and you release more string by tapping the bottom of the head on the ground while the trimmer is running. A small clutch mechanism inside the head releases a set length of string (usually 2-3 inches) each time you tap.
• Fixed-line: Also called “manual feed,” this system requires you to manually pull out a set length of string each time it wears down. There is no automatic feed mechanism, so you’ll need to stop trimming, turn off the weed eater, and pull out new string when the existing line is too short.
• Dual-line: This system uses two separate strands of string, which cut more efficiently and cover a wider area than single-line models. Dual-line trimmers can be either bump-feed or fixed-line, depending on the model.

Common String Diameters and Materials

Weed eater string comes in a range of diameters and materials, and using the correct type for your model and use case will improve performance and extend the life of both the string and your trimmer. The most common string diameters are:

• .065 inch: Ideal for light grass and weeds in small, well-maintained yards. This thin string is easy to cut through soft vegetation but will break quickly if used on thick brush or near hard surfaces.
• .080 inch: The most versatile size, suitable for medium to thick grass, weeds, and light brush. This is the standard size for most residential weed eaters.
• .095 inch and larger: Designed for thick, woody brush, overgrown areas, and commercial use. This thick string is durable but puts more strain on smaller electric or battery-powered trimmers, so always check your manual before using it.

Most residential string is made of durable nylon. Round string is the most common and works well for general use, square string has sharp edges that cut through thick vegetation more efficiently, and serrated string has tooth-like edges that are ideal for dense, woody weeds.

Safety Precautions Before You Start

Working on a weed eater is generally low-risk, but taking a few basic safety precautions will prevent injuries and damage to your tool. Follow these steps before you begin any string replacement:

1. Disconnect the power source completely: For gas-powered weed eaters, turn off the engine, let it cool for at least 15 minutes (the muffler gets extremely hot during use), then disconnect the spark plug wire to prevent accidental starting. For electric models, unplug the cord from the outlet. For battery-powered models, remove the battery from the tool.
2. Wear protective gear: Put on a pair of work gloves to protect your hands from sharp string edges, and safety glasses to protect your eyes from flying debris when you test the trimmer after installing new string. Closed-toe shoes are also recommended to protect your feet if you drop the trimmer head.
3. Clear your work area: Make sure you’re working on a flat, stable surface, and remove any tripping hazards like hoses, toys, or garden tools from the area around you.
4. Inspect the trimmer for damage: Before you start, check the trimmer shaft, trimmer head, and spool for cracks or damage. If you notice any broken parts, replace them before installing new string to avoid further damage or injury.

Tools and Materials Required

You don’t need any special tools to replace weed eater string, and most of the items you’ll need are either included with your trimmer or easy to find at any hardware store. Gather these items before you start:

• Replacement weed eater string (correct diameter for your model, as specified in your user manual)
• Scissors or a dedicated string trimmer line cutter
• Clean, dry rag
• Flathead screwdriver or the trimmer head wrench that came with your weed eater (most models include this in the box)
• Work gloves and safety glasses

Note: Some newer weed eater models have a quick-release trimmer head that lets you remove and replace the spool without tools. If your model has this feature, you won’t need the wrench or screwdriver.

Step-by-Step: How to Put String on My Weed Eater (Bump-Feed Model)

Bump-feed trimmers are the most common type for residential use, and replacing the string is a straightforward process. Follow these steps carefully to ensure the string feeds correctly:

1. Remove the trimmer head: Use the trimmer head wrench or flathead screwdriver to loosen the retaining nut or bolt that holds the trimmer head to the drive shaft. Turn the nut counterclockwise to loosen it, then remove the nut and pull the trimmer head straight off the shaft. Set the nut aside in a safe place so you don’t lose it during the process.
2. Empty any remaining old string: Pull out all leftover broken, worn, or tangled string from the spool inside the trimmer head. Discard the old string in the trash.
3. Clean the spool and trimmer head: Wipe away any grass clippings, dirt, or old string residue from the spool and the inside of the trimmer head with a clean rag. Buildup of debris can cause the string to jam or feed unevenly, so this step is important for smooth operation.
4. Measure and cut the new string: Most bump-feed models require 10 to 15 feet of string, but check your user manual for the exact recommended length for your model. Cut the string to length with scissors or a line cutter. If you have a dual-line bump-feed model, cut two equal lengths of string.
5. Thread the string through the spool eyelet: Locate the small hole (eyelet) on the side of the spool. Thread one end of the string through the eyelet, leaving about 2 to 3 inches of string sticking out the opposite side to hold it in place while you wind.
6. Wind the string onto the spool: Wind the string tightly and evenly around the spool, following the direction of the arrow printed on the spool (almost always clockwise). Do not overlap the string as you wind, as this will cause jams and uneven feeding. Leave about 6 inches of string hanging out the bottom of the spool, which will be the portion that extends when you tap the head on the ground.
7. Secure the string end: Tuck the loose end of the string into the small notch on the edge of the spool to keep it from unraveling while you reassemble the trimmer head.
8. Reassemble the trimmer head: Align the spool with the trimmer head, making sure the string feeds through the small exit hole at the bottom of the head. Place the retaining nut back on the drive shaft, hand-tighten it first to avoid cross-threading, then use the wrench to tighten it securely. Do not overtighten the nut, as this can crack the plastic trimmer head.
9. Test the feed: Reconnect the spark plug, power cord, or battery, then turn on the weed eater. Tap the bottom of the trimmer head on the ground while it’s running – you should see 2 to 3 inches of string extend each time you tap. If the string does not feed, double-check that you wound the string in the correct direction and that the end is tucked into the notch properly.

Step-by-Step: How to Put String on My Weed Eater (Fixed-Line Model)

Fixed-line trimmers don’t have an automatic feed mechanism, so you’ll need to manually pull out new string each time it wears down. The replacement process is similar to bump-feed models, with a few small differences:

1. Disconnect power and remove the trimmer head: Just like with bump-feed models, first disconnect the power source, then use the wrench or screwdriver to loosen the retaining nut, remove the nut, and pull the trimmer head off the drive shaft.
2. Remove the old string: Pull out all remaining string from the spool and the small line port on the side of the trimmer head housing.
3. Clean the spool and line port: Wipe away any grass, dirt, or debris from the spool and the line port with a clean rag. A clogged line port will prevent new string from feeding correctly.
4. Cut the new string to length: Most fixed-line models require 10 to 12 feet of string, but check your user manual for the exact length. Cut one long piece of string to size.
5. Thread the string through the line port: Locate the small line port on the side of the trimmer head housing (not the spool itself). Thread one end of the string through this port, leaving about 2 inches of string sticking out the opposite side of the port.
6. Wind the string onto the spool: Wind the string tightly and evenly around the spool, following the clockwise direction indicated on the spool. Leave about 6 inches of string hanging out the bottom exit hole of the trimmer head.
7. Secure the string end: Tuck the loose end of the string into the notch on the spool to prevent it from unraveling while you work.
8. Reassemble the trimmer head: Align the spool with the trimmer head, making sure the string feeds through the bottom exit hole. Replace the retaining nut and tighten it securely, but do not overtighten.
9. Test the line: Reconnect the power source and turn on the weed eater. Let it run for a few seconds – the string should extend automatically as it wears down. If it does not, check that the string is properly seated in the line port and wound in the correct direction.

Step-by-Step: How to Put String on My Weed Eater (Dual-Line Model)

Dual-line weed eaters use two strands of string for more cutting power and coverage, making them ideal for thick weeds and large yards. The replacement process is similar to single-line models, but you’ll need to wind two separate spools:

1. Disconnect power and remove the trimmer head: Follow the same steps as with single-line models to disconnect the power source and remove the trimmer head from the drive shaft.
2. Remove old string: Pull out all remaining string from both spools inside the trimmer head, and from the line ports on the side of the head.
3. Clean the spools and head: Wipe away all debris from both spools, the line ports, and the inside of the trimmer head to prevent jams.
4. Cut two equal lengths of string: Most dual-line models require two 10 to 15 foot pieces of string of the same diameter. Cut them to exactly the same length to ensure even cutting and feeding.
5. Thread each string through its respective eyelet: Each spool has its own small eyelet on the side. Thread one end of each string through its corresponding eyelet, leaving 2 to 3 inches of string sticking out the opposite side to hold it in place while you wind.
6. Wind each string onto its spool: Wind each string tightly and evenly around its respective spool, following the clockwise direction indicated on the spool. Leave about 6 inches of string hanging out the bottom of each spool.
7. Secure both string ends: Tuck the loose end of each string into the notch on its respective spool to prevent unraveling.
8. Reassemble the trimmer head: Align both spools with the trimmer head, making sure each string feeds through its own separate exit hole at the bottom of the head. Replace the retaining nut and tighten it securely, but do not overtighten.
9. Test the feed: Reconnect the power source and turn on the weed eater. If you have a bump-feed dual-line model, tap the head on the ground to extend both lines. If you have a fixed dual-line model, let it run for a few seconds to check that both lines extend evenly. If one line does not feed, double-check that it is wound in the correct direction and seated properly in its exit hole.

Tips for Extending String Life and Improving Performance

Once you know how to put string on your weed eater, you can take a few simple steps to extend the life of your string and keep your trimmer running at peak performance:

• Use the correct string size for your needs: Always use the string diameter recommended by your trimmer’s manufacturer. For light grass and small yards, .065 inch string is sufficient. For thicker weeds and larger yards, use .080 inch string. Only use .095 inch or larger string if your trimmer is designed for heavy-duty use, as it can damage smaller electric or battery-powered motors.
• Avoid cutting near hard surfaces: Rocks, pavement, fences, and tree trunks wear down weed eater string much faster than soft grass and soil. Try to trim a few inches away from these surfaces to extend the life of your string.
• Keep the string at the recommended length: Most weed eaters perform best with 4 to 6 inches of string extending from the trimmer head. Longer string creates extra drag on the motor, reducing power and wearing the string out faster. If your string extends longer than this after feeding, trim it to the correct length with scissors.
• Clean the trimmer head regularly: Grass clippings, dirt, and debris can build up inside the trimmer head, causing jams and uneven string wear. Wipe out the head after every few uses to keep it running smoothly.
• Use the right string shape for your use case: Round string works well for general grass trimming, but if you regularly cut thick, woody weeds, use square or serrated string, which cuts more efficiently and wears down slower.

Common Mistakes to Avoid When Replacing Weed Eater String

Even experienced DIYers make mistakes when replacing weed eater string, but avoiding these common issues will save you time and frustration:

• Winding the string in the wrong direction: This is the most common mistake, and it will prevent the string from feeding correctly. Always wind the string in the clockwise direction indicated by the arrow on the spool. If you wind it counterclockwise, the feed mechanism will not be able to release the string when you tap the head or pull it out.
• Overlapping the string while winding: Winding the string loosely or overlapping layers will cause jams and uneven feeding. Wind the string tightly and evenly, with no gaps or overlaps between layers.
• Using the wrong string size: As mentioned earlier, using a string that’s too small will break easily, while a string that’s too large will damage the trimmer head and motor. Always check your user manual for the recommended size before buying replacement string.
• Overtightening the retaining nut: It’s tempting to tighten the nut as much as possible to keep the trimmer head from falling off, but overtightening can crack the plastic trimmer head or strip the threads on the drive shaft. Hand-tighten the nut first, then use a wrench to snug it gently – it should be tight enough that the head doesn’t wiggle, but not so tight that you have to force it.
• Skipping the safety step of disconnecting power: Never work on a weed eater that’s still connected to a power source or has a hot engine. Accidental starting is one of the most common causes of injury when working on power equipment, so always disconnect the spark plug, unplug the cord, or remove the battery before you start.

Comparison: Bump-Feed vs Fixed-Line vs Dual-Line Systems

If you’re shopping for a new weed eater or trying to decide which type is best for your yard, this comparison table breaks down the key differences between the three most common feed systems:

Frequently Asked Questions

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

The frequency of string replacement depends on how often you use your trimmer and the type of vegetation you cut. For light use (trimming a small yard once a week), you’ll likely only need to replace the string every 2 to 3 months. For heavy use (cutting thick brush weekly), you may need to replace it every few weeks. You’ll know it’s time to replace the string when it’s worn down to less than 2 inches, or breaks frequently during use.

Can I use any size string on my weed eater?

No, always use the string size recommended by your weed eater’s manufacturer. Using a string that’s too small will break easily and won’t cut effectively. Using a string that’s too large will put extra strain on the motor, cause the trimmer head to overheat, and can damage the drive shaft. You can find the recommended size in your user manual or printed on the trimmer head.

Why does my weed eater string keep breaking?

Frequent string breakage is almost always caused by one of a few common issues: using the wrong string size, cutting too close to hard surfaces like rocks or pavement, winding the string incorrectly on the spool, a damaged or misaligned trimmer head, or using old, brittle string. To fix the issue, first confirm you’re using the correct string size, then inspect the trimmer head for damage, and make sure you’re winding the string tightly and evenly in the correct direction.

Do I need to wear gloves when handling weed eater string?

Yes, it’s highly recommended to wear work gloves when handling and installing weed eater string. The edges of new string are extremely sharp, and can easily cut your hands. Gloves also protect your hands from sharp edges on the trimmer head while cleaning the spool. Safety glasses are also recommended to protect your eyes from flying debris when testing the trimmer after installation.

Can I use a weed eater without string?

No, never operate a weed eater without string installed. The string is the cutting component of the tool, and running it without string will cause the internal mechanism to spin without resistance, which can loosen the spool, overheat the drive shaft, and cause permanent motor damage. Always ensure you have the correct length of string installed and feeding properly before use.

Conclusion

Learning how to put string on your weed eater is a simple, practical skill that every yard maintenance enthusiast should master. Instead of spending money on a new trimmer when your string wears down, you can replace it in minutes with basic tools and a few dollars worth of replacement line. We covered the three most common feed systems – bump-feed, fixed-line, and dual-line – with step-by-step instructions for each, plus safety tips, best practices for extending string life, common mistakes to avoid, and answers to common questions. Remember to always disconnect the power source before starting work, use the correct string size for your model, and wind the string in the clockwise direction indicated on the spool to avoid jams. With these tips, you can keep your weed eater running smoothly all season long, no matter how much yard work you have to do.