Introduction
Stihl is one of the most trusted names in outdoor power equipment, and their weed eaters (also called string trimmers) are a staple for homeowners and landscaping professionals alike. If you’ve ever wondered How to String Weed Eater Stihl, you’re not alone—replacing the cutting line is one of the most routine maintenance tasks for these tools, and doing it yourself can save you $20 to $50 per service visit while keeping your equipment in peak condition. This comprehensive guide walks you through every step of the process, tailored to the two most common Stihl weed eater head types, plus tips, troubleshooting advice, and answers to frequently asked questions to ensure you get the job done right the first time.
- Why You Need to Replace Your Stihl Weed Eater String Regularly
- Types of Stihl Weed Eater String and Compatibility
- Tools and Safety Gear You’ll Need
- How to String Weed Eater Stihl: Step-by-Step for Bump Feed Models
- How to String Weed Eater Stihl: Step-by-Step for Fixed Line Models
- Comparison Table: Bump Feed vs Fixed Line Stringing for Stihl Weed Eaters
- Pro Tips for Extending Your Stihl Weed Eater String Life
- Common Mistakes to Avoid When Stringing a Stihl Weed Eater
- Troubleshooting Common Post-Stringing Issues
- Frequently Asked Questions
- Conclusion
Why You Need to Replace Your Stihl Weed Eater String Regularly
Your Stihl weed eater’s cutting line takes a beating with every use. Friction against grass, weeds, rocks, pavement, and even soil wears down the string over time, causing it to become frayed, thin, and eventually break. Worn string cuts less efficiently, leaving you with uneven edges and missed patches of weeds, and it also puts excess strain on the weed eater’s engine, which can lead to reduced performance and costly repairs over time. Additionally, frayed or broken string can throw debris unpredictably, creating a safety hazard for you, your family, and nearby property. Most casual users will need to replace their string every 2 to 4 weeks with regular use, while heavy-duty or commercial users may need to replace it every few days. Replacing the string regularly is one of the simplest and most cost-effective ways to keep your Stihl weed eater running like new.
Types of Stihl Weed Eater String and Compatibility
Not all weed eater string is created equal, and using the wrong type for your Stihl model can lead to poor performance, jams, and even damage to your tool. Stihl designs their equipment to work with specific string types, diameters, and materials, so it’s important to choose the right option for your needs:
- Round string: The most common and affordable option, round string has a smooth, circular cross-section. It’s ideal for light-duty use, such as trimming grass around sidewalks, gardens, and fences. It’s compatible with nearly all Stihl bump feed and fixed line heads, and is the best choice for most residential users.
- Square (serrated) string: Square string has sharp, angled edges that cut more aggressively than round string, making it perfect for thick weeds, overgrown brush, and dense vegetation. It wears down faster than round string, but delivers much cleaner cuts for heavy-duty jobs. It’s compatible with most Stihl bump feed and fixed line heads, but check your user manual to confirm.
- Octagonal string: Octagonal string has eight sharp edges, delivering the most cutting power of any Stihl string type. It’s designed for commercial use, thick brush, and very dense vegetation, but requires a high-powered Stihl model to operate effectively. It’s not recommended for small residential weed eaters, as it can overload the engine.
In addition to shape, string diameter is critical for compatibility. Most residential Stihl models use 0.080-inch (2.0 mm) diameter string, while commercial-grade models use 0.095-inch (2.4 mm) or 0.105-inch (2.7 mm) diameter. Using string that’s too thick will jam the head and overload the engine, while string that’s too thin will break easily and cut poorly. The correct diameter for your model is listed in your user manual and printed on a sticker on the side of the weed eater head.
Tools and Safety Gear You’ll Need
Before you start stringing your Stihl weed eater, gather the following tools and safety gear to make the process smooth and safe:
- Replacement Stihl-compatible string, cut to the correct length for your head type
- Work gloves (to protect your hands from sharp string edges)
- Safety glasses (to protect your eyes from debris when testing the weed eater)
- Small flathead screwdriver or the included Stihl spool removal tool (most Stihl heads come with a small plastic tool for removing the spool cap)
- Clean rag (to wipe away grass, sap, and debris from the head)
- Needle-nose pliers (optional, for gripping and removing stubborn spools)
- Tape measure (optional, for cutting string to the correct length)
Before you begin any work on your weed eater, follow these critical safety steps:
- Place the weed eater on a flat, stable surface to prevent it from tipping over while you work.
- Disconnect the spark plug wire from the spark plug to prevent accidental startup. This is the most important safety step, as an unexpected startup can cause serious injury.
- Remove the cutting guard if it obstructs access to the head, and set it aside in a safe place.
- Keep children and pets away from the work area to avoid accidents.
How to String Weed Eater Stihl: Step-by-Step for Bump Feed Models
Bump feed is the most common head type for residential Stihl weed eaters. It uses a pre-wound spool with two strands of string, and releases more line when you bump the head lightly on the ground. Follow these steps to string a Stihl bump feed weed eater correctly:
Preparing the Weed Eater
Lay the weed eater on a flat surface with the head facing up. Disconnect the spark plug wire to prevent accidental startup. Remove the plastic cutting guard if it blocks access to the spool cap, and set it aside. Inspect the feed holes in the head to make sure they are not clogged with grass, sap, or debris—clogged holes will prevent string from extending even if the spool is loaded correctly. Clear any blockages with a small screwdriver or your finger.
Removing the Old Spool
Locate the spool release knob at the base of the head, usually marked with a spool icon. Turn the knob counterclockwise to loosen it, then remove the spool cap and set it aside. Pull the old spool straight out of the head. If it’s stuck, gently wiggle it while pulling—do not use excessive force, as this can damage the internal feed mechanism. Remove any remaining old string from the spool, and wipe out the head housing with your clean rag to remove all grass and debris.
Winding the New String
Cut two equal lengths of Stihl-compatible string, each 10 to 15 feet long (check your user manual for the exact length recommended for your model). Look for the directional arrow on the bottom of the new spool—this arrow shows which direction to wind the string to ensure proper feeding. Insert one end of the string into the small anchor hole on the spool, then pull it tight so it does not slip out. Wind the string tightly and evenly in the direction of the arrow, overlapping each layer slightly to avoid gaps and tangles. Leave 4 to 6 inches of string sticking out of the winding, then repeat the process with the second strand, winding in the same direction. Make sure the two string ends are on opposite sides of the spool, not next to each other, to prevent tangling when you bump the head. (See Also:How To Take Head Off Milwaukee Weed Eater)
Reassembling the Spool
Align the small tabs on the edge of the spool with the slots in the head housing, then push the spool firmly into place until you hear a click, indicating it is seated correctly. Thread the two string ends through the eyelets on the spool cap, then screw the cap back on clockwise until it is tight. Reattach the cutting guard if you removed it earlier.
Testing the Feed
Reconnect the spark plug wire to the spark plug. Start the weed eater following the starting instructions in your user manual. Hold the weed eater with the head facing away from you and any bystanders, then bump the head lightly on a smooth concrete surface 2 to 3 times. You should see 2 to 3 inches of new string extend from the head with each bump. If the string does not feed, turn off the weed eater, disconnect the spark plug, and check that the string is wound tightly in the correct direction with no tangles. If the string feeds too much or too little, adjust the feed knob on the side of the head (if your model has one) to control the feed rate.
How to String Weed Eater Stihl: Step-by-Step for Fixed Line Models
Fixed line heads do not use a wound spool. Instead, you load a single solid strand of string directly into the head, and the line feeds out automatically as it wears down. Fixed line heads are most common on commercial-grade Stihl weed eaters, and are preferred by professional landscapers for their durability and resistance to tangling. Follow these steps to string a Stihl fixed line weed eater:
Preparing the Fixed Line Head
Lay the weed eater on a flat surface with the head facing up. Disconnect the spark plug wire to prevent accidental startup. Locate the line release lever or knob on the side of the head, usually marked with a line icon. Release the lever to open the line loading compartment. Inspect the feed slots and cutting blades at the end of the head for any burrs, sharp edges, or damage. Smooth out any burrs with a small file, and sharpen or replace dull cutting blades to prevent fraying the new line as it exits the head.
Removing the Old Line
Pull out any remaining old line from the head and discard it. Wipe out the loading compartment and feed slots with a clean rag to remove all grass, sap, and debris. Check the locking mechanism for the line to make sure it moves freely and is not clogged with dirt.
Installing the New Line
Cut a single length of Stihl-compatible string to the length specified in your user manual, typically 10 to 12 feet for most fixed line models. Insert one end of the string into the feed slot on the side of the head, pushing it through the slot and into the center of the head until it emerges from the opposite side. Pull the string tight to remove all slack, making sure it is seated properly in the feed slots.
Securing and Testing the Fixed Line
Engage the locking mechanism on the side of the head to hold the string in place. Trim the excess string with a pair of scissors or the edge of the cutting blade to match the length of the original line, usually 10 to 12 inches from the center of the head to the tip. Reconnect the spark plug wire, start the weed eater, and test the cut on a patch of grass to ensure the line feeds smoothly and cuts evenly. If the line does not feed, turn off the weed eater, disconnect the spark plug, and check that the string is seated correctly in the feed slots and the locking mechanism is engaged.
Comparison Table: Bump Feed vs Fixed Line Stringing for Stihl Weed Eaters
Bump feed and fixed line heads each have their own advantages and disadvantages, depending on your use case. Use the comparison below to decide which system is right for you, and to understand the differences in the stringing process:
| Feature | Bump Feed | Fixed Line |
|---|---|---|
| String Type Used | Pre-wound spools with 2 strands of round, square, or octagonal line | Single solid strand of square or octagonal line, cut to length by the user |
| Replacement Frequency | Every 2-4 weeks with regular residential use, more often for heavy-duty cutting | Every 4-6 weeks with regular use, with a longer overall lifespan for most users |
| Ease of Stringing | Very simple, no special skills required, takes 5 to 10 minutes for most users | Moderate difficulty, requires precise cutting and alignment, takes 10 to 15 minutes for most users |
| Best Use Case | Residential use, light grass and weed trimming, edging around sidewalks and gardens | Commercial use, thick brush, heavy weeds, large properties, and professional landscaping |
| Cost per Replacement | $5 to $15 for pre-wound Stihl-branded spools | $3 to $10 for bulk string sold by the roll |
| Durability | Moderate, prone to tangling if not wound correctly, and can jam if overfilled | High, very resistant to tangling and jamming, even with heavy use |
Pro Tips for Extending Your Stihl Weed Eater String Life
With a few simple habits, you can extend the life of your Stihl weed eater string by 50% or more, reducing how often you need to replace it and saving you money on replacement parts. Follow these pro tips to get the most out of your string: (See Also:How To Change Milwaukee Weed Eater Head)
- Always use string that meets the exact diameter and type specifications for your Stihl model, as listed in your user manual. Using thicker or heavier string than recommended puts excess strain on the engine and wears the string down much faster.
- Wipe the string and head clean after each use to remove grass, sap, dirt, and other debris that can cause fraying and premature wear. A quick wipe with a clean rag takes less than a minute and can double the life of your string.
- Avoid bumping the head on concrete, gravel, or other abrasive surfaces excessively when using bump feed models, as this frays the string ends and causes them to break more quickly. Bump the head only on smooth, soft surfaces like grass when possible.
- Store replacement string in a cool, dry place away from direct sunlight, as UV exposure can make plastic string brittle and prone to breaking over time. Avoid storing string in hot garages or sheds where temperatures can exceed 100°F.
- For fixed line models, sharpen the cutting blades at the end of the head every 10 to 15 hours of use. Dull blades fray new line as it exits the head, causing it to break much faster than it would with sharp blades.
- If you only use your weed eater occasionally or are storing it for the winter, remove the string entirely from the head. String left in the head for long periods can develop a “set” or warp, leading to poor feeding and tangling when you use the tool again.
Common Mistakes to Avoid When Stringing a Stihl Weed Eater
Even experienced users make avoidable mistakes when stringing their Stihl weed eater, leading to poor performance, jams, and even damage to the tool. Avoid these common errors to make the process faster and ensure your weed eater works perfectly after restrung:
- Winding the string in the wrong direction: Nearly all Stihl spools have a small directional arrow printed on the bottom, indicating which way to wind the string for proper feeding. Winding in the opposite direction will cause the string to jam and not extend when you bump the head. Always check the arrow before you start winding, and wind in the exact direction it points.
- Using the wrong string diameter or type: Stihl designs each model to work with a specific string size and shape, and using the wrong option will cause poor performance and damage. Check your user manual for the correct specifications, and never use string that is thicker, thinner, or heavier than recommended.
- Overfilling the spool: It may seem like a good idea to wind as much string as possible onto the spool to reduce how often you need to replace it, but overfilling causes the string to overlap and tangle, leading to jams and poor feeding. Leave a small 1/8-inch gap between the wound string and the edge of the spool to allow for smooth movement.
- Failing to disconnect the spark plug wire: Skipping this critical safety step can lead to accidental startup while you’re working on the head, which can cause serious lacerations or other injuries. Always disconnect the spark plug wire first, before touching any internal parts of the weed eater.
- Misaligning the spool tabs when reassembling: Bump feed spools have small tabs on the edge that must align with slots in the head housing to seat correctly. If you push the spool in without aligning the tabs, it will not sit properly, and the string will not feed. Make sure the tabs click into the slots before pushing the spool all the way in.
- Not tightening the spool cap enough: If the spool cap is not screwed on tightly, the spool can come loose while the weed eater is running, leading to damage to the head or even injury from flying parts. Always turn the cap clockwise until it stops turning, and give it an extra quarter turn to ensure it is secure.
Troubleshooting Common Post-Stringing Issues
If you’ve just restrung your Stihl weed eater and it’s not working as expected, don’t worry—most issues are easy to fix with a few simple adjustments. Here are the most common post-stringing problems and their solutions:
- String won’t extend when bumping the head (bump feed models): This is almost always caused by tangled string, winding in the wrong direction, or overfilling the spool. Turn off the weed eater, disconnect the spark plug, remove the spool, and check that the string is wound tightly in the correct direction with no tangles. If the spool is overfilled, remove a few layers of string and try again.
- String breaks immediately after starting: This is usually caused by using string that’s too thin for your model, or dull cutting blades at the end of the head. Replace the string with the correct diameter for your model, and sharpen or replace the cutting blades if they are worn or damaged.
- Weed eater runs but doesn’t cut: If the engine runs but the string isn’t cutting grass, the string is likely worn down to less than 2 inches long, or the cutting blades are dull. Replace the string, and sharpen or replace the blades to restore cutting performance.
- String feeds too much or too little at once: For bump feed models, adjust the feed knob on the side of the head (if your model has one) to control how much string is released per bump. For fixed line models, trim the excess line to the length specified in your user manual to ensure consistent feeding.
- String jams in the head: Jams are usually caused by tangled string, debris in the head housing, or using string that’s too thick. Turn off the weed eater, disconnect the spark plug, remove the spool or line, clear out any debris, and reload the string correctly with the proper diameter.
Frequently Asked Questions
How often should I change the string on my Stihl weed eater?
The frequency of string replacement depends on how often you use your weed eater and what you’re cutting. For light residential use (trimming grass around sidewalks and gardens once a week), you’ll typically need to replace the string every 3 to 4 weeks. If you’re cutting thick weeds or using the weed eater on abrasive surfaces like gravel, you may need to replace it every 1 to 2 weeks. You’ll know it’s time to replace the string when it becomes frayed, worn down to less than 3 inches long, or when cutting performance drops significantly.
What size string does my Stihl weed eater use?
The correct string size for your Stihl weed eater is listed in your user manual and printed on a sticker on the side of the head or near the engine. Most residential models use 0.080-inch (2.0 mm) diameter string, while commercial models use 0.095-inch (2.4 mm) or 0.105-inch (2.7 mm). Using the wrong size can cause jams, poor performance, and engine damage.
Can I use third-party string instead of Stihl branded string?
Yes, as long as it meets your model’s exact specifications for diameter, shape, and material. Stihl’s branded string is optimized for their heads, but high-quality third-party options work just as well and are more affordable. Avoid cheap, low-quality string, as it can break easily, jam the head, and damage internal components.
Why is my Stihl weed eater string eating itself?
This is usually caused by winding the string in the wrong direction, overfilling the spool, or using string that’s too thick for your model. To fix it, remove the spool, unwind the string, and rewind it tightly in the correct direction (follow the arrow on the bottom of the spool) without overfilling. If the problem persists, confirm you’re using the correct string diameter for your model. (See Also:How To Wind Husqvarna Weed Eater)
How long should the string be on a Stihl weed eater?
For bump feed models, 4 to 6 inches of string should stick out of the head after bump feeding. For fixed line models, trim the string to 10 to 12 inches from the center of the head to the tip. Too-long string strains the engine and causes overheating, while too-short string requires frequent bumping and wears out the feed mechanism faster.
Can I string a Stihl weed eater without the included winding tool?
Yes, a small flathead screwdriver works just as well as the official Stihl tool for removing the spool cap and winding the string, as long as you’re careful not to damage plastic components. Many users also wind the string by hand, which is fine for most models as long as it’s wound tightly and evenly.
Conclusion
Knowing How to String Weed Eater Stihl is a simple but valuable skill that every Stihl owner should have. Replacing the cutting line yourself saves you money on professional service calls, reduces downtime when your string breaks mid-job, and helps extend the overall lifespan of your weed eater by preventing unnecessary strain on the engine. This guide covered everything you need to know, from choosing the right string type for your model to step-by-step instructions for both bump feed and fixed line heads, a comparison of the two systems, pro tips to extend string life, common mistakes to avoid, and troubleshooting advice for common issues. By following these steps and using the right parts for your model, you can keep your Stihl weed eater performing at its best for years to come. Bookmark this guide for future reference, and always consult your model’s user manual for specific specifications and safety guidelines.