How to Put Weed Eater String on Stihl? Complete Stihl Model Instructions

Introduction

If you own a Stihl trimmer, you’ve likely wondered How to Put Weed Eater String on Stihl? at some point. Stihl is one of the most trusted brands in outdoor power equipment, and their trimmers are built to last for years with proper maintenance. Replacing the trimmer string (also called line) is one of the most routine, cost-effective upkeep tasks you can perform, and it eliminates the need to buy a new spool or even a whole new trimmer when your line runs out. Many homeowners assume this task is complicated, but with the right guidance, you can load Stihl string in 5 minutes or less, regardless of whether you have a gas, electric, or battery-powered model, or a bump feed or fixed line trimmer head. This complete guide walks you through every step of the process, including model-specific instructions for popular Stihl trimmers, safety tips, common mistakes to avoid, and answers to frequently asked questions. By the end, you’ll have all the knowledge you need to tackle this task confidently and keep your Stihl trimmer running at peak performance.

Table of Contents

• Why You Should Master Replacing Stihl Weed Eater String
• Essential Tools and Materials You’ll Need
• Choosing the Right Weed Eater String for Your Stihl Model
• Safety Precautions Before You Start
• How to Put Weed Eater String on Stihl: General Step-by-Step Guide (Bump Feed Models)
• Loading String on Stihl Fixed Line Models
• Model-Specific Instructions for Popular Stihl Trimmers
• Common Mistakes to Avoid When Loading Stihl String
• Tips for Extending Your String’s Lifespan
• Troubleshooting Common String Issues
• Frequently Asked Questions
• Conclusion

Why You Should Master Replacing Stihl Weed Eater String

Learning how to replace your Stihl trimmer string isn’t just a convenience—it’s a smart way to save money and reduce waste over time. Pre-loaded replacement spools from Stihl can cost $15 to $30 each, and if you use your trimmer regularly, you’ll go through multiple spools per year. By loading your own string, you can cut that cost by 70% or more, as bulk Stihl-approved string costs just $5 to $10 for a 50-foot roll that will last for dozens of replacements. Beyond cost savings, mastering this task means you’ll never have downtime when your string runs out mid-yard work. You can swap it out in minutes instead of waiting for a replacement spool to ship or driving to the hardware store. Additionally, choosing your own string lets you customize your trimmer’s performance for your specific yard: if you have thick, overgrown weeds, you can opt for a heavy-duty square or star-shaped line, while light grass and edging work calls for a thinner, more flexible round line. Finally, proper string loading reduces wear and tear on your trimmer’s gearbox and engine, extending the overall lifespan of your Stihl equipment.

Essential Tools and Materials You’ll Need

Before you start loading string, gather these simple tools to make the process fast and frustration-free:

• Stihl-approved weed eater string: Always use the gauge and shape recommended for your specific Stihl model to avoid damage to the trimmer head or poor cutting performance. Using non-approved string can also void your warranty.
• Wire cutters or heavy-duty scissors: To cut the string to the correct length.
• Work gloves: To protect your hands from sharp string edges and any rough parts of the trimmer head.
• Safety glasses: To protect your eyes from flying debris or snapped string.
• Small flathead screwdriver (optional): For prying off stubborn spool caps that are stuck due to dirt or debris.
• Clean rag: To wipe down the trimmer head and remove any built-up grass or dirt before loading new string.

You won’t need any specialized mechanical tools for this task, which is part of what makes it so accessible for DIY homeowners and renters alike.

Choosing the Right Weed Eater String for Your Stihl Model

One of the most common mistakes people make when learning how to put weed eater string on Stihl is using the wrong type or size of string. Stihl designs their trimmer heads to work with specific string gauges (thickness) and shapes, and using the wrong option can cause poor cutting performance, frequent breakage, or even damage to the trimmer’s gearbox. First, check your Stihl manual for the recommended string size, which is typically listed in the specifications section. Common gauges for Stihl trimmers range from 0.065″ for light-duty residential models to 0.120″ for heavy-duty commercial-grade trimmers.

Beyond gauge, string shape also impacts performance. Below is a comparison of the most common Stihl-compatible string types to help you choose the right option for your needs:

If you’re unsure which string to choose, opt for Stihl’s own branded line, which is engineered specifically for their trimmer heads and comes in all common gauges and shapes for every model they sell.

Safety Precautions Before You Start

While loading Stihl string is a low-risk task, taking a few basic safety steps will prevent injuries and damage to your trimmer. Follow these precautions every time you work on your equipment:

1. Disconnect power completely: For gas-powered Stihl trimmers, remove the spark plug boot from the spark plug to prevent accidental starting. For electric corded models, unplug the trimmer from the outlet. For battery-powered models, remove the battery pack fully—don’t just turn the trimmer off, as a faulty switch could still engage the head.
2. Wear personal protective equipment (PPE): Always wear work gloves and safety glasses, even for quick string swaps. Sharp string edges can cut skin, and snapped string can fly at high speed and cause eye injuries.
3. Work on a stable surface: Place your trimmer on a flat workbench or the ground in a well-lit area so you don’t have to balance it while loading string.
4. Let a hot trimmer cool down: If you just used your Stihl, wait 10 to 15 minutes for the engine and trimmer head to cool before handling them to avoid burns.
5. Keep children and pets away: Even with the power disconnected, keep small children and animals away from your work area to avoid accidents.

These simple steps take less than 2 minutes and will keep you safe while you work.

How to Put Weed Eater String on Stihl: General Step-by-Step Guide (Bump Feed Models)

Bump feed is the most common trimmer head type for Stihl residential and commercial trimmers. This system releases more string automatically when you bump the bottom of the trimmer head against the ground while cutting. Follow these steps to load string on any Stihl bump feed model:

1. Disconnect power and remove the spool cap: First, disconnect power using the steps outlined in the safety section. Locate the spool cap at the bottom of the trimmer head. Most Stihl bump feed heads have small release tabs on the side of the cap; press these in and twist the cap counterclockwise to remove it. If your cap is stuck, use a small flathead screwdriver to gently pry it loose.
2. Remove the old spool and clean the head: Pull the old spool out of the trimmer head. Use a clean rag to wipe away any built-up grass, dirt, or old string fragments from the inside of the head and the spool grooves. This ensures the new string feeds smoothly without tangling.
3. Cut the new string to the correct length: Measure out 10 to 15 feet of new string, or check your Stihl manual for the exact length recommended for your model. Most bump feed spools require enough string to wrap around the spool 2 to 3 times, plus an extra 6 inches for the free end. Use wire cutters to cut the string cleanly.
4. Anchor the string to the spool: Find the small anchor hole (also called a retention hole) in the center of the spool. Insert one end of the cut string into this hole and pull it through until there is about 1 inch of string left on the other side of the hole. This keeps the string from slipping as you wind it.
5. Wind the string around the spool: Look for an arrow printed on the top of the spool—this indicates the direction you should wind the string (almost always clockwise for Stihl spools). Wrap the string tightly and evenly around the spool, following the grooves if your spool has them. Do not overfill the spool: leave a 1/4-inch gap between the wound string and the edge of the spool to prevent jamming.
6. Leave a free end for feeding: Once you’ve finished winding, pull the free end of the string out of the anchor hole and leave 4 to 6 inches of string sticking out. This is the length that will feed through the trimmer head when you bump it.
7. Thread the string through the trimmer head: Insert the free end of the string into the eyelet (small hole) on the side of the trimmer head, and pull it through until the end reaches the bottom of the head.
8. Reinstall the spool and cap: Place the wound spool back into the trimmer head, making sure the string sits in the grooves of the head and the free end is aligned with the eyelet. Twist the spool cap clockwise until it clicks into place, making sure it is fully tightened to prevent the spool from falling out during use.
9. Test the feed: Reconnect power to your trimmer. Turn it on and bump the bottom of the head against the ground 2 to 3 times. You should see 6 to 8 inches of string extend automatically. If the string doesn’t feed, double-check that you wound it in the correct direction and that the free end is long enough.

This general process works for nearly all Stihl bump feed models, including the popular FS 56 RC and FSA 90. For model-specific tweaks, see the dedicated section below.

Loading String on Stihl Fixed Line Models

Some Stihl trimmers, especially heavy-duty commercial models, use a fixed line head instead of a bump feed spool. Fixed line heads don’t use a wound spool; instead, you cut a length of string, thread it through eyelets on the head, and secure it with a knot. This design is more durable for heavy-duty use and reduces tangling. Follow these steps to load fixed line on your Stihl trimmer: (See Also:How To String A Greenworks Pro Weed Eater 2)

1. Disconnect power and remove the trimmer head cover: As with bump feed models, first disconnect all power to the trimmer. Locate the screws or clips holding the trimmer head cover in place, and remove the cover to access the eyelets.
2. Cut the string to length: Cut a 10 to 12 foot length of Stihl-approved string for your model. For most fixed line heads, you’ll need two equal lengths of string, one for each side of the head.
3. Thread the first string: Take one length of string and insert one end through the bottom eyelet on the trimmer head. Pull 6 inches of string through the eyelet so the end hangs below the head.
4. Tie a secure knot: Tie a tight overhand knot in the end of the string that is hanging below the eyelet. This knot prevents the string from slipping through the eyelet during use. Trim any excess string hanging below the knot, leaving only 1/4 inch of tail.
5. Thread the second string: Take the second length of string and insert one end through the top eyelet on the opposite side of the head. Pull the string through until both ends are equal in length (usually 6 to 8 inches each).
6. Reattach the head cover: Place the trimmer head cover back over the head and secure it with the screws or clips you removed earlier. Make sure the cover is tightened fully to prevent it from coming loose during use.
7. Test the trimmer: Reconnect power and turn on the trimmer. The string should be rigid and extend fully when you rev the engine. If the string slips, double-check that your knots are tight and that you’re using the correct string gauge for your model.

Fixed line heads are most common on Stihl’s commercial-grade trimmers like the FS 94 R and FS 130, but some residential models also offer fixed line as an optional head upgrade.

Model-Specific Instructions for Popular Stihl Trimmers

While the general steps above work for most Stihl trimmers, a few popular models have unique quirks that are worth noting. Below are step-by-step adjustments for the most common Stihl trimmers homeowners and renters use:

Stihl FS 56 RC (Gas, Bump Feed)

The FS 56 RC is one of Stihl’s best-selling residential gas trimmers, and it uses the AutoCut 2-2 bump feed head. To load string on this model:

1. Press the two release tabs on the side of the spool cap and twist it counterclockwise to remove.
2. Use 0.080″ square or round Stihl string, cut to 12 feet in length.
3. Wind the string around the spool in the direction of the arrow (clockwise) for 2 full turns, leaving 6 inches of free end sticking out of the eyelet.
4. Do not overfill the spool: the wound string should sit 1/4 inch below the top edge of the spool.
5. Reinstall the spool, twist the cap clockwise until it clicks, and test the feed by bumping the head on the ground.

Stihl FSA 90 (Battery, Bump Feed)

The FSA 90 is a popular battery-powered trimmer for homeowners, with a twist-lock spool system that’s even easier to use than gas models:

1. First, remove the battery pack from the bottom of the trimmer to fully disconnect power.
2. Twist the spool cap counterclockwise to unlock it, then pull it straight off the head.
3. Use 0.080″ Stihl string cut to 10 feet in length. The FSA 90’s spool is smaller than gas models, so you don’t need as much string.
4. Anchor the string to the center of the spool, wind it clockwise for 1.5 to 2 turns, and leave 5 inches of free end.
5. Thread the free end through the eyelet, reinstall the spool, twist the cap clockwise until it locks into place, and reattach the battery to test.

Stihl FS 94 R (Gas, Fixed Line Optional)

The FS 94 R is a heavy-duty commercial trimmer that can use either a bump feed spool or a fixed line head. For fixed line loading:

1. Remove the 4 screws holding the trimmer head cover in place and pull the cover off.
2. Use 0.110″ or 0.120″ star-shaped Stihl string for maximum durability. Cut two 12-foot lengths of string.
3. Thread one end of each string through the bottom and top eyelets respectively, tie tight overhand knots below each eyelet, and trim excess tails.
4. Reattach the head cover and tighten the screws fully. The FS 94 R puts more strain on the string than residential models, so make sure your knots are extra tight to prevent slipping.

If you have a different Stihl model, consult your owner’s manual for the exact string size and loading instructions, as some older or specialty models may have unique requirements.

Common Mistakes to Avoid When Loading Stihl String

Even experienced DIYers make these common errors when loading Stihl string, which can lead to poor performance, frequent breakage, or damage to your trimmer. Avoid these pitfalls:

• Winding the string in the wrong direction: If you wind the string counterclockwise instead of following the arrow on the spool, the string will not feed properly when you bump the head, and it may even tangle inside the spool. Always double-check the arrow before you start winding.
• Overfilling the spool: It’s tempting to add as much string as possible to the spool to avoid frequent replacements, but overfilling causes the string to jam and prevents it from feeding smoothly. Leave a 1/4-inch gap between the wound string and the top of the spool at all times.
• Using the wrong string gauge: String that is too thick will not fit through the eyelet or will jam in the spool, while string that is too thin will break frequently and not cut effectively. Always use the gauge recommended in your Stihl manual.
• Not leaving enough free string: If you leave less than 4 inches of string sticking out of the eyelet, the bump feed mechanism will not be able to grab the string to release more. Always leave at least 4 to 6 inches of free end after loading.
• Skipping the cleaning step: Failing to wipe down the trimmer head and spool before loading new string can cause dirt and grass to get trapped between the spool and head, leading to jamming and uneven string feed.
• Not tightening the spool cap: A loose spool cap can cause the spool to fall out mid-use, leading to lost string and potential damage to the trimmer head. Always twist the cap until it clicks or feels fully tightened.

Avoiding these mistakes will make the string loading process faster and ensure your trimmer works as intended for weeks after each replacement.

Tips for Extending Your String’s Lifespan

Once you’ve mastered how to put weed eater string on Stihl, you can take a few extra steps to make your string last longer, reducing how often you need to replace it:

• Avoid hitting hard obstacles: The #1 cause of premature string breakage is hitting rocks, concrete, curbs, or tree trunks while trimming. If you need to edge along a hard surface, adjust the trimmer’s cutting angle so the string barely touches the surface, or use a dedicated edger for those areas.
• Use the right string for your terrain: If you have rocky soil or lots of thick brush, upgrade to a heavier star-shaped string that resists breakage better than round line.
• Keep the string trimmed to the correct length: Most Stihl bump feed trimmers work best with 6 to 8 inches of extended string. If the string gets too long, it can whip around and break more easily, or put extra strain on the engine. Use wire cutters to trim it back to the recommended length if needed.
• Store extra string in a cool, dry place: UV light and moisture can weaken string over time, making it more prone to breakage. Keep your extra string in a sealed plastic bag in a garage or shed away from direct sunlight.
• Don’t overload the trimmer: Trying to cut through thick, woody brush or dense, wet grass will put extra strain on the string and cause it to break faster. For heavy vegetation, use a brush cutter attachment instead of the standard trimmer line.

With these tips, you can extend the life of your Stihl string by 2 to 3 times, saving you even more money and time over the course of a year.

Troubleshooting Common String Issues

Even after loading your string correctly, you may run into occasional issues with your Stihl trimmer. Here are fixes for the most common problems: (See Also:How To Use Black And Decker Weed Eater)

String won’t feed when I bump the head

This is almost always caused by one of three issues: you wound the string in the wrong direction, there is not enough free string sticking out of the eyelet, or the spool is jammed with dirt. First, check the direction the string is wound—if it’s counterclockwise, rewind it correctly. Next, make sure at least 4 inches of string is sticking out of the eyelet. If both of these are correct, remove the spool and clean out any built-up grass or dirt from the head and spool grooves.

String breaks constantly while trimming

Frequent breakage is usually due to using the wrong string gauge, hitting hard obstacles, or having a dull trimmer head. First, confirm you’re using the correct string size for your model. If you are, check if you’re hitting rocks or concrete while trimming. If not, the cutting blades on your trimmer head may be dull and need to be replaced.

String tangles inside the spool

Tangling happens when the spool is overfilled, the string is wound unevenly, or the free end is not threaded correctly through the eyelet. Remove the spool, cut off the tangled string, and reload it following the steps in this guide, making sure to wind it tightly and evenly, and leave the correct amount of free string.

String feeds too much or too little when bumping

Adjust the feed rate by turning the adjustment knob on the bottom of the bump feed head (if your model has one). Turning the knob clockwise reduces the amount of string released per bump, while turning it counterclockwise increases the feed rate. If your head doesn’t have an adjustment knob, make sure you’re only leaving 4 to 6 inches of free string, as longer free ends will release too much string per bump.

Frequently Asked Questions

Below are answers to the most common questions about loading Stihl weed eater string:

How often should I replace my Stihl weed eater string?

For most residential users, you’ll need to replace your string every 2 to 4 weeks, depending on how often you use the trimmer and what type of vegetation you’re cutting. If you notice the string is frayed, broken, or not cutting effectively, it’s time to replace it, even if it hasn’t been a full month.

Can I use third-party string on my Stihl trimmer?

Yes, you can use third-party string as long as it matches the gauge and shape recommended for your Stihl model. However, Stihl’s own branded string is engineered specifically for their trimmer heads and tends to last longer and perform better than generic options. Using non-approved string may also void your trimmer’s warranty if it causes damage.

What size string does my Stihl model use?

The recommended string size for your model is listed in your owner’s manual, on a sticker on the trimmer body, or on the original replacement spool packaging. Common sizes range from 0.065″ for light-duty residential models to 0.120″ for heavy-duty commercial trimmers. If you can’t find the information, contact Stihl customer support with your model number for assistance. (See Also:How To Remove Homelite Weed Eater Head)

Why does my string keep coming loose after loading?

A loose string is almost always caused by not tightening the spool cap fully, or not anchoring the string securely to the spool before winding. Make sure you insert the string fully into the anchor hole and pull it tight before winding, and twist the spool cap until it clicks into place. For fixed line models, make sure your knots are tight and the head cover is fully secured.

Can I load Stihl string in the rain?

It’s best to load string in a dry, covered area. Moisture can cause the string to slip while you’re winding it, and dirt or water can get trapped in the trimmer head, leading to jamming and corrosion over time. If you must load string in damp conditions, wipe the trimmer head and spool dry with a clean rag first.

How do I know if my Stihl uses bump feed or fixed line?

Check your owner’s manual, or look at the trimmer head: bump feed heads have a round, spool-shaped base with a bump knob on the bottom, while fixed line heads have a flat base with two small eyelets on the sides for threading string. If you’re still unsure, Stihl’s website has a model lookup tool that will tell you what head type your trimmer uses.

Conclusion

Learning how to put weed eater string on Stihl is a simple, valuable skill that will save you time, money, and hassle for as long as you own your trimmer. Whether you have a small residential bump feed model like the FSA 90 or a heavy-duty commercial fixed line trimmer like the FS 94 R, the steps outlined in this guide will help you load string quickly and correctly every time. Remember to always use the right string for your model, follow safety precautions, and avoid common mistakes like overfilling the spool or winding the string in the wrong direction. With a little practice, you’ll be able to swap out your Stihl string in 5 minutes or less, keeping your yard looking neat and your trimmer running like new. If you run into any issues that aren’t covered here, consult your Stihl owner’s manual or contact Stihl’s customer support team for model-specific guidance.