How to Change Weed Eater String on Stihl? Beginner’s Guide

Introduction

Stihl trimmers are a top choice for homeowners and landscaping professionals, known for their durability, power, and consistent performance. Over time, the cutting line on your Stihl weed eater will wear down, fray, or break from regular contact with grass, weeds, and hard surfaces. Many beginners assume replacing this line requires a trip to a repair shop, but learning how to change weed eater string on Stihl is a simple, 10-minute task that saves you time and money. This beginner-friendly guide walks you through every step of the process, from gathering tools to troubleshooting common issues, for all Stihl gas, electric, and battery-powered models. We also cover how to pick the right replacement string, avoid common mistakes, and extend your line’s lifespan with expert best practices.

Table of Contents

• Why You Need to Change Your Stihl Weed Eater String Regularly
• Tools and Materials You’ll Need
• Safety Precautions Before You Start
• How to Identify Your Stihl Trimmer Model
• Step-by-Step Guide to Changing Weed Eater String on Stihl
• Replacing String on Bump Feed Stihl Models
• Replacing String on Fixed Line Stihl Models
• How to Choose the Right Replacement String for Your Stihl
• Comparison of Common Stihl Weed Eater String Types
• Tips and Best Practices for Extending String Life
• Common Mistakes to Avoid When Changing Stihl String
• Troubleshooting Common Post-Replacement Issues
• Frequently Asked Questions
• Conclusion

Why You Need to Change Your Stihl Weed Eater String Regularly

Many Stihl trimmer owners wait until their cutting line is completely broken or frayed beyond use before replacing it, but this habit can reduce your trimmer’s performance and cause costly long-term damage. Worn or dull line requires extra power from the motor to cut through vegetation, increasing fuel consumption for gas models, draining battery life faster for cordless units, and putting unnecessary strain on the engine and drive shaft. Over time, this extra strain can lead to expensive repairs, including worn bearings or a damaged trimmer head. Worn string also leaves uneven, ragged cuts on grass and weeds, and is far more likely to snap mid-use, leaving you with an incomplete job. Replacing your string as soon as you notice fraying, dullness, or reduced cutting power keeps your Stihl trimmer running at peak performance and extends its overall lifespan. For most users, replacing the line every 2-3 months of regular use is a simple maintenance habit that saves time and money in the long run.

Tools and Materials You’ll Need

Gathering all necessary tools before starting the replacement process will help you work quickly and avoid interruptions. You will need the following items:

• Replacement Stihl weed eater string: Confirm you purchase the correct diameter for your model (most Stihl trimmers use 0.080-inch or 0.095-inch line; check your owner’s manual to be sure).
• Sharp scissors or dedicated line cutter: Dull cutting tools fray string ends, leading to frequent jams and breakage.
• Flathead screwdriver: Used to loosen the screw securing the trimmer head to the drive shaft.
• Work gloves: Sharp new line can cut your fingers when pulling it through tight head holes.
• Safety glasses: Protect your eyes from flying debris while working.
• Small brush or rag: Used to clean grass and debris out of the trimmer head before installing new line.

You can purchase pre-cut line lengths or full spools at most hardware stores, home improvement centers, or Stihl dealerships. Avoid low-quality generic string, as it will wear out faster and may not fit properly in your Stihl trimmer head.

Safety Precautions Before You Start

Working with power tools requires basic safety steps to avoid injury, even for a simple task like string replacement. First, if you have a gas-powered Stihl trimmer, turn off the engine and let it cool completely before starting work, as hot engine components can cause serious burns. Disconnect the spark plug wire to prevent accidental starting while you work on the head. For battery-powered models, remove the battery pack from the trimmer base to ensure the tool has no power. Always wear safety glasses and work gloves during the process, as sharp line can cause cuts and debris can fly into your eyes. Finally, work in a well-lit, open area so you can see all parts of the trimmer head clearly and avoid tripping over tools or the trimmer itself.

How to Identify Your Stihl Trimmer Model

Stihl produces a wide range of weed eaters, including gas-powered, electric corded, and battery-powered models, each with slightly different trimmer head designs. Identifying your specific model will help you confirm the correct string size, feed type, and any model-specific replacement steps. The model number is printed on a label on the trimmer’s shaft below the handle, or on the bottom of the trimmer head. Common Stihl models include the FS 56 RC (gas-powered, bump feed), FS 94 R (heavy-duty gas bump feed), and FSA 90 (battery-powered bump feed). If you can’t find the model number, check your owner’s manual, which will also list the recommended string diameter for your unit. Most Stihl trimmers use either 0.080-inch (2.0 mm) or 0.095-inch (2.4 mm) line, with larger diameters reserved for heavy-duty models designed to cut thick brush and weeds.

Step-by-Step Guide to Changing Weed Eater String on Stihl

Once you have your tools ready and have taken safety precautions, you can start the replacement process. The exact steps vary slightly depending on whether your Stihl trimmer uses a bump feed system (the most common type, where you tap the head on the ground to release more line) or a fixed line system (where you manually feed line through holes in the head). We cover both types below.

Replacing String on Bump Feed Stihl Models

Bump feed trimmers are the most popular Stihl models for residential and light commercial use, as they let you release more line mid-use without stopping work. Follow these steps to replace the string on your bump feed Stihl trimmer:

1. Remove the trimmer head from the shaft: Locate the screw securing the head to the drive shaft. Use your flathead screwdriver to loosen the screw, then pull the head straight off the shaft. Set the screw aside in a safe place to avoid losing it.
2. Remove the old line spool: Press the tabs on the side of the head cover to release it, then pull the spool out of the head. If the spool is stuck, gently wiggle it back and forth to loosen it. Discard any remaining old line from the spool.
3. Clean the trimmer head: Use your brush or rag to remove built-up grass, dirt, and debris from inside the head and spool. Gunk buildup is a leading cause of line jams, so this step is critical for smooth operation.
4. Prepare the new line: Cut a 10-15 foot length of replacement string with sharp scissors or a line cutter. A clean, smooth cut prevents frayed ends that cause jams.
5. Wind the line onto the spool: Thread one end of the new line through the small hole in the center of the spool, leaving 6 inches of line sticking out. Wind the line evenly around the spool in the direction of the arrow printed on the spool (all Stihl spools have a directional arrow to indicate correct winding). Do not overfill the spool; leave 1/2 inch of space between the wound line and the spool edge to avoid jams. Tuck the loose end into the small notch on the spool to hold it in place once fully wound.
6. Reassemble the trimmer head: Thread the loose end of the line through the exit hole in the head, then slide the spool back into the head, making sure it seats in the grooves. Snap the head cover back into place until the tabs click securely.
7. Reattach the head to the shaft: Slide the head back onto the drive shaft, aligning the holes. Insert the screw you removed earlier and tighten it securely, but do not over-tighten, as this can crack the plastic head.
8. Test the feed: Reconnect the spark plug or reinsert the battery, then turn on the trimmer. Tap the head on the ground while running; 4-6 inches of line should release with each tap. If the line does not feed, turn off the trimmer and double-check that you wound the line in the correct direction and the spool is seated properly.

Replacing String on Fixed Line Stihl Models

Fixed line trimmers do not use a wound spool; instead, you manually feed short lengths of line through small holes in the head, securing the ends with tabs or knots. These models are less common for residential use but are popular for heavy-duty commercial applications. Follow these steps to replace the string on your fixed line Stihl trimmer:

1. Remove the trimmer head from the shaft: Loosen the screw securing the head to the drive shaft with your flathead screwdriver, then pull the head off the shaft and set the screw aside.
2. Remove the old line: Pull the old line out of the holes in the head. If it is stuck, use your screwdriver to gently pry it out, being careful not to damage the plastic head or holes.
3. Clean the trimmer head: Brush out any debris, grass, or dirt from the holes in the head to ensure the new line feeds smoothly.
4. Cut the new line to length: Measure the distance between the two line holes in the head, then add 4-6 inches to that length. Cut two equal lengths of replacement string with sharp scissors or a line cutter.
5. Feed the line through the holes: Insert one end of a line length into one of the head holes, pushing it through until it sticks out 2 inches on the other side. Repeat with the second line length, feeding it through the opposite hole. Both ends should stick out roughly the same distance on both sides of the head.
6. Secure the line ends: Tuck the loose ends into the small tabs or notches on the outside of the head holes, or tie a small overhand knot in each end if your head does not have tabs, to prevent the line from pulling through during use.
7. Trim the line to the correct length: Use your line cutter to trim both ends so they are even and extend no more than 6 inches from the head (check your owner’s manual for the recommended length for your model). Excessively long line causes excess vibration and reduces cutting efficiency.
8. Reassemble the trimmer: Slide the head back onto the drive shaft, align the holes, insert the screw, and tighten it securely. Test the trimmer on a patch of grass to ensure the line cuts evenly and does not wobble.

How to Choose the Right Replacement String for Your Stihl

Using the correct string for your Stihl trimmer is critical for performance and longevity. When shopping for replacement line, focus on three key factors: diameter, shape, and material.

First, confirm the correct diameter for your model. Most residential Stihl trimmers use 0.080-inch (2.0 mm) line, while heavy-duty commercial models use 0.095-inch (2.4 mm) line. You can find this information in your owner’s manual, on the label on your trimmer’s shaft, or printed on your existing line spool. Using a line that is too thick will overload the motor and jam the head, while a line that is too thin will break frequently and cut poorly.

Second, choose the right shape for your use case. Round string is the most affordable option, ideal for light grass and edging on residential lawns. Square or star-shaped string has sharp edges that slice through thick weeds and brush more efficiently, making it a better choice for overgrown yards or commercial use. Twisted string is more durable than round line and resists fraying, making it a great all-around option for mixed vegetation.

Finally, opt for high-quality nylon string. Low-quality nylon becomes brittle in cold weather and frays quickly when cutting abrasive surfaces like concrete or rocky soil. Stihl’s branded string is designed to work seamlessly with their trimmer heads, but there are many reliable third-party options that meet the same quality standards.

Comparison of Common Stihl Weed Eater String Types

To help you choose the best string for your needs, here is a comparison of the most common types of cutting line compatible with Stihl trimmers:

For most beginners, a 0.080-inch twisted or square string is the best all-around choice, as it balances durability and cutting efficiency for typical residential use. If you regularly cut thick brush or woody weeds, opt for a 0.095-inch star or square string to avoid frequent breakage.

Tips and Best Practices for Extending String Life

Follow these simple tips to get the most out of your Stihl weed eater string and reduce how often you need to replace it:

• Cut string to the correct length: For bump feed models, cut a 10-15 foot length before winding. For fixed line models, cut the line 4-6 inches longer than the distance between the two head holes. Excessively long line causes excess vibration and reduces cutting efficiency.
• Wind line evenly and tightly: When winding bump feed spools, wrap the line tightly with no gaps or overlapping layers. Even winding prevents the line from catching and jamming during use.
• Leave space in the spool: Always leave at least 1/2 inch of space between the wound line and the edge of the spool. Overfilling blocks line movement and causes frequent jams.
• Clean the head during every replacement: Brush out grass, dirt, and debris from the trimmer head before installing new line. Built-up gunk is a leading cause of line jams and feeding issues.
• Store spare string properly: Keep unused spool in a cool, dry, shaded place. Nylon line becomes brittle when exposed to direct sunlight or extreme temperatures, reducing its lifespan.
• Use high-quality string: Opt for Stihl-branded or high-quality third-party nylon string. Low-quality string frays quickly, breaks easily, and wears out far faster than premium options.

Common Mistakes to Avoid When Changing Stihl String

Even experienced users make errors when replacing Stihl string, leading to jams, breakage, and poor performance. Avoid these common pitfalls:

• Winding line in the wrong direction: This is the top cause of bump feed jams. Always wind the line in the direction of the arrow printed on the spool to ensure smooth feeding.
• Using the wrong string diameter: A line that is too thick jams the head and overloads the motor, while a line that is too thin breaks frequently. Always confirm the correct size for your model before purchasing replacement string.
• Overfilling the spool: Packing the spool tightly with line leaves no room for movement, causing the line to bind and jam. Stick to the 1/2 inch gap rule to avoid this.
• Not securing the line end: After winding the line onto the spool, tuck the loose end into the notch on the spool. A loose end will unravel mid-use, leaving you without cutting line unexpectedly.
• Using dull cutting tools: Dull scissors or cutters fray the ends of the string, creating weak points that break easily during use. Sharpen your cutting tools regularly for clean, smooth cuts.
• Skipping the head cleaning step: Failing to remove grass and debris from the trimmer head before installing new line will almost always lead to jams within a few uses.

Troubleshooting Common Post-Replacement Issues

Even with correct installation, you may encounter minor issues after replacing your Stihl string. Here are quick fixes for the most common problems:

• Line does not feed when bumping the head: First, confirm you wound the line in the direction of the arrow on the spool. Next, check that the spool is seated correctly in the head and the cover is snapped shut. Overfilled spools can also block line movement, so unwind 1-2 feet of line if the spool is packed tightly.
• Line breaks frequently during use: This is usually caused by using string that is too thin for the vegetation you’re cutting, or frayed ends from dull cutting tools. Switch to a thicker diameter line, and always cut new string with sharp scissors to avoid frayed ends that weaken the line.
• Excessive vibration after replacement: Unevenly wound line or overly long line will cause the trimmer to vibrate. Turn off the tool, remove the head, and check that the line is wrapped tightly and evenly on the spool. Trim the line to the recommended length for your model if it extends more than 6 inches from the head.
• Line feeds too much or too little per bump: If too much line releases, you overfilled the spool; remove the spool and unwind a few feet of line. If too little line releases, check that the spool is not stuck in the head and that the line is wound tightly enough to move freely.

Frequently Asked Questions

How often should I change my Stihl weed eater string?

For most residential users, replace the string every 2-3 months of regular use, or as soon as you notice fraying, dullness, or reduced cutting power. Commercial users cutting thick vegetation may need to replace it every 4-6 weeks. Replacing it early avoids unnecessary strain on the trimmer’s motor.

Can I use generic string on my Stihl trimmer?

Yes, as long as the generic string matches the correct diameter and shape for your model. Low-quality third-party string frays quickly and breaks easily, but high-quality options work well for most users. Stihl’s branded string is engineered for their heads to reduce jams and extend line life.

What size string does my Stihl trimmer use?

Most residential Stihl models use 0.080-inch (2.0 mm) line, while heavy-duty commercial models use 0.095-inch (2.4 mm) line. Check your owner’s manual, trimmer shaft label, or existing spool to confirm the correct size. Using the wrong diameter causes jams and poor performance.

Why does my Stihl string keep jamming?

Jams are almost always caused by winding the line in the wrong direction, overfilling the spool, using frayed low-quality string, or failing to clean debris from the trimmer head. Fix these issues to eliminate most jams.

Do I need to break in new Stihl string?

No, Stihl string is ready to use immediately after installation. Minor fraying during the first 1-2 uses is normal as the line’s sharp edges wear down. Excessive breakage usually indicates you are using the wrong diameter string or dull cutting tools.

Conclusion

Learning how to change weed eater string on Stihl is a simple, valuable skill that every Stihl trimmer owner should master. Not only does it save you the cost and hassle of professional repairs, but regular string replacement also keeps your tool running at peak performance, extends its lifespan, and ensures clean, even cuts every time you use it. By following the step-by-step guide in this article, gathering the right tools, and avoiding common mistakes, even complete beginners can replace their Stihl trimmer string in 10 minutes or less. Remember to always use the correct string size and type for your model, clean the trimmer head before installing new line, and wind the line in the correct direction to avoid jams. With proper maintenance, your Stihl weed eater will stay reliable and efficient for years to come, making yard work faster and easier every season.