Introduction
Changing the cutting line on a Stihl weed eater is a routine maintenance task that keeps the tool performing at its best. Whether you own a homeowner model or a professional‑grade trimmer, knowing how to change Stihl weed eater string correctly saves time, reduces frustration, and extends the life of the cutting head. This guide walks you through every step, from identifying the type of head on your machine to selecting the right diameter line and winding it without tangles. By the end you will feel confident tackling the job yourself, without a trip to the service shop.
- Understanding the Trimmer Head
- Types of Trimmer Heads
- Tools and Materials Needed
- Safety Precautions
- Step‑by‑Step Guide
- Choosing the Right Trimmer Line
- Winding the Line Correctly
- Maintenance Tips for Longer Line Life
- Common Mistakes to Avoid
- Frequently Asked Questions
- Conclusion
Understanding the Trimmer Head
The trimmer head is the rotating assembly that holds the cutting line. On most Stihl models the head is either a bump‑feed, a fixed‑line, or an automatic‑feed design. Each style feeds line differently, so the replacement procedure varies slightly. Before you start, locate the model number on the housing and consult the owner’s manual for the exact head type. Knowing the head design prevents you from forcing components and damaging the spool or the drive shaft.
Types of Trimmer Heads
Stihl offers three common head configurations. The bump‑feed head releases new line when you tap the head on the ground. The fixed‑line head uses a pre‑cut length of line that you insert manually and does not advance automatically. The automatic‑feed head uses a spring‑loaded mechanism that advances line as it wears. Understanding the differences helps you choose the right replacement line and follow the correct winding method.
| Head Type | Line Feed Method | Typical Line Diameter | Ease of Reload |
|---|---|---|---|
| Bump‑Feed | Tap to advance | 0.080‑0.095 in | Moderate |
| Fixed‑Line | Manual insert | 0.080‑0.105 in | Easy |
| Automatic‑Feed | Spring‑loaded advance | 0.080‑0.095 in | Moderate |
Tools and Materials Needed
Gather the following items before you begin: a replacement spool of Stihl‑approved trimmer line (matching the diameter recommended for your head), a pair of heavy‑duty gloves, safety glasses, a clean rag, and a small flat‑head screwdriver or the proprietary Stihl head‑release tool if your model includes one. Having everything at hand prevents interruptions and keeps the work area tidy.
Safety Precautions
Always disconnect the spark plug wire or remove the battery pack before servicing the trimmer. Wear gloves to protect your hands from sharp line ends and safety glasses to shield your eyes from debris. Work on a stable, flat surface and keep the cutting head away from your body. Never attempt to change the line while the engine is running or the battery is connected.
Step‑by‑Step Guide
Follow the sequence below for a smooth line change. The steps are grouped by head type where the procedure diverges.
Preparing the Trimmer
- Turn off the engine and disconnect the spark plug wire or remove the battery.
- Lay the trimmer on a clean workbench with the cutting head facing up.
- Remove any debris or grass buildup from the head housing using a rag.
Removing the Old Line
- Locate the head‑release button or screw. Press the button or unscrew the retaining cap.
- Pull the spool straight out of the housing. On bump‑feed heads the spool may be held by a spring; compress the spring gently.
- Unwind any remaining line from the spool and discard it. Inspect the spool for cracks or excessive wear; replace the spool if damaged.
Installing New Line on Bump‑Feed Head
- Cut two equal lengths of line, each about 10‑12 feet long (or the length specified in the manual).
- Insert one end of each line into the anchor holes on the spool, following the directional arrows molded into the spool.
- Wind the line tightly and evenly in the direction indicated, keeping the two strands side by side without crossing.
- Leave about 6 inches of line protruding from each eyelet for the bump‑feed mechanism to grab.
- Reinsert the spool into the housing, ensuring the spring (if present) seats correctly.
- Snap the retaining cap back on or press the release button until it clicks.
Installing New Line on Fixed‑Line Head
- Cut a single piece of line to the length recommended by the manufacturer (usually 8‑10 feet).
- Thread one end through the eyelet on the spool and pull it through until the line is centered.
- Wind the line in the direction of the arrow, keeping tension even.
- Leave a short tail (about 4 inches) extending from the eyelet for the initial cut.
- Place the spool back into the head and secure the cap.
Installing New Line on Automatic‑Feed Head
- Open the head cover by releasing the latch or unscrewing the cap.
- Remove the old spool and discard any remaining line.
- Insert a new pre‑wound spool designed for automatic‑feed heads, or wind fresh line onto the existing spool following the same winding direction as the bump‑feed method.
- Make sure the line passes through the feed eyelet and the spring tensioner is engaged.
- Close the cover and lock the latch.
Reattaching the Head and Testing
- Reconnect the spark plug wire or reinstall the battery pack.
- Start the trimmer and let it idle for a few seconds.
- For bump‑feed heads, gently tap the head on the ground to advance line; for automatic heads, the line should feed automatically.
- Check that the line cuts cleanly and that there is no excessive vibration.
Choosing the Right Trimmer Line
Line diameter, shape, and material affect cutting performance and durability. Stihl recommends using their own brand of line because it is engineered to match the head’s feed mechanism. Common diameters range from 0.080 inch for light residential work to 0.105 inch for heavy brush. Round line is standard, but twisted or serrated profiles can improve cutting efficiency on tough weeds. Always verify the maximum line diameter listed in the owner’s manual; using oversized line can jam the head and damage the motor.
Winding the Line Correctly
Proper winding prevents line crossover, which causes feeding problems and uneven wear. Keep the line under consistent tension as you wind, and follow the directional arrows on the spool. If the spool has two separate chambers (dual‑line), wind each strand into its own chamber without letting them intersect. After winding, press the line firmly into the spool’s retaining slots so it cannot unwind during operation. A well‑wound spool feeds smoothly and reduces the frequency of reloads.
Maintenance Tips for Longer Line Life
- Store the trimmer in a dry place; moisture makes line brittle.
- Clean the head after each use to remove grass sap that can glue line together.
- Inspect the spool and eyelets for wear every few sessions; replace worn parts promptly.
- Use the correct line diameter; undersized line wears quickly, oversized line stresses the motor.
- Sharpen the cutting edge of the line by lightly tapping the head on a hard surface if the line becomes dull.
Common Mistakes to Avoid
One frequent error is crossing the two strands on a dual‑line spool, which creates a jam that stops the bump‑feed action. Another mistake is over‑filling the spool; excess line can bind against the housing and cause the motor to stall. Using non‑Stihl line that is too soft or too hard also leads to premature breakage or feeding issues. Finally, neglecting to disconnect the power source before servicing is a safety hazard that can result in serious injury.
Frequently Asked Questions
How often should I change the trimmer line?
Line replacement frequency depends on usage intensity and vegetation type. For typical residential lawns, expect to reload every 2‑3 hours of cutting time. Heavy brush or commercial use may require a new spool every hour.
What line size does my Stihl model need?
Check the specifications plate on the trimmer or the owner’s manual. Most homeowner models use 0.080‑0.095 inch line, while professional units may accept up to 0.105 inch.
Can I use universal trimmer line instead of Stihl brand?
Universal line can work if it matches the exact diameter and shape recommended for your head. However, Stihl‑engineered line is optimized for the feed mechanism and generally lasts longer.
My bump‑feed head won’t advance line. What should I do?
First, ensure the spool is wound in the correct direction and that the two strands are not crossed. Clean any debris from the feed eyelet. If the problem persists, the internal spring may be worn and the head may need replacement.
Conclusion
Mastering how to change Stihl weed eater string empowers you to keep your trimmer running efficiently without costly service visits. By identifying your head type, gathering the proper tools, and following the step‑by‑step winding procedure, you ensure clean cuts and longer line life. Regular maintenance, correct line selection, and avoiding common pitfalls will keep your Stihl trimmer ready for any yard task. With practice, the process becomes second nature, letting you focus on a well‑manicured landscape.