How to String a Stihl Fs50c Weed Eater? Easy Start Spool

Introduction

Learning how to string a Stihl Fs50c weed eater is a fundamental maintenance skill that keeps your trimmer running smoothly and extends the life of the cutting head. The Stihl FS 50C features the Easy Start spool system, which simplifies line replacement but still requires the correct technique to avoid jams, uneven feed, or premature wear. This guide walks you through every stage—from gathering the right tools to testing the finished spool—so you can confidently restring the trimmer yourself. Whether you are a homeowner tackling weekend yard work or a landscaping professional looking for a quick refresher, the step‑by‑step instructions, practical tips, and common‑mistake warnings below will help you achieve a clean, reliable line feed every time.

• Understanding the Stihl FS 50C Trimmer Head
• Tools and Materials Needed
• Safety Precautions
• Removing the Old Spool
• Preparing the New Line
• Step‑by‑Step: Stringing the Easy Start Spool
• Reinstalling the Spool and Testing
• Comparison Table: Stihl FS 50C vs. Other Models
• Tips and Best Practices
• Common Mistakes and How to Avoid Them
• Frequently Asked Questions
• Conclusion

Understanding the Stihl FS 50C Trimmer Head

The FS 50C uses a dual‑line, bump‑feed head that relies on centrifugal force to advance the cutting line. The Easy Start spool is a pre‑wound cartridge that snaps into the head without the need for manual winding. Inside the spool, two line channels guide the nylon strands outward; a spring‑loaded retainer holds the line in place until the head spins fast enough to release a measured length. Knowing the geometry of these channels helps you insert the new line correctly and prevents the line from crossing or binding. The head also features a small inspection window that lets you verify line length without fully disassembling the unit. Familiarity with these components makes the restringing process faster and reduces the chance of damaging the delicate spring mechanism.

Tools and Materials Needed

Before you begin, gather the following items to ensure a smooth workflow:

• Replacement trimmer line (typically .095 in. diameter for the FS 50C)
• Easy Start spool cartridge compatible with the FS 50C
• Clean shop rag or paper towels
• Small flat‑head screwdriver (for any retaining clips)
• Protective gloves and safety glasses
• Owner’s manual for reference specifications

Having the correct line diameter is critical; using a thicker line can overload the motor, while a thinner line may break prematurely. The Easy Start spool eliminates the need for a separate winding tool, but a screwdriver may be required to release the spool lock on some production runs.

Safety Precautions

Always treat the trimmer as a powered cutting tool even when the engine is off. Follow these safety steps before you start:

1. Disconnect the spark plug wire to prevent accidental ignition.
2. Allow the engine to cool completely if it has been running.
3. Wear safety glasses to protect your eyes from stray line fragments.
4. Use gloves to avoid cuts from the sharp nylon line.
5. Work on a stable, flat surface with good lighting.

These precautions reduce the risk of injury and protect the trimmer’s internal components from debris that could enter during disassembly.

Removing the Old Spool

Start by locating the spool release button on the side of the trimmer head. Press the button firmly while turning the spool counter‑clockwise; the spool should detach from the drive shaft. If the spool is stuck, gently tap the head with a rubber mallet to loosen any corrosion. Once free, pull the spool straight out and set it aside. Inspect the old line for wear patterns—uneven wear often indicates a misaligned feed or a damaged spring. Clean the head cavity with a rag to remove grass clippings, dirt, and old line fragments that could interfere with the new spool’s operation.

Preparing the New Line

If you are using a bulk spool rather than a pre‑wound Easy Start cartridge, cut two equal lengths of line, each about 12 feet long. This length provides enough material for several feed cycles without excessive waste. Thread one end of each line through the corresponding eyelet on the spool body, following the directional arrows molded into the plastic. Pull the line through until roughly 6 inches protrude from each side. Ensure the line lies flat in the channel without twists; twisted line can cause feeding problems and premature breakage. For the Easy Start cartridge, simply verify that the line is already seated correctly in the channels and that the retaining tabs are intact.

Step‑by‑Step: Stringing the Easy Start Spool

1. Align the spool: Hold the new Easy Start spool with the label facing up. Match the spool’s drive lugs to the slots on the trimmer head.
2. Insert the spool: Push the spool onto the drive shaft until you hear a click, indicating the locking tabs have engaged.
3. Secure the spool: If your model uses a retaining screw, tighten it with the flat‑head screwdriver just enough to hold the spool firmly—over‑tightening can crack the plastic.
4. Feed the line: Pull the free ends of the line outward until they extend about 3 inches beyond the head’s cutting radius. This initial feed ensures the bump‑feed mechanism has line to advance on the first tap.
5. Check line tension: Gently tug each line; it should feel snug but not overly tight. Excessive tension can cause the line to snap under load.
6. Reconnect the spark plug: Reattach the spark plug wire, ensuring a solid connection.
7. Test run: Start the engine and let it idle. Tap the head lightly on the ground to engage the bump feed. Observe that line advances evenly on both sides.

Adjusting Line Length and Tension

If the line feeds too much or too little, adjust the length by pulling or releasing a small amount of line from the spool before the next test run. The ideal cutting length is typically 4–5 inches beyond the head’s outer edge. Proper tension prevents the line from slapping against the guard, which reduces vibration and improves cutting efficiency.

Reinstalling the Spool and Testing

After confirming the line feeds correctly, reinstall any protective covers or guards that were removed. Double‑check that all screws are snug and that the spool rotates freely without wobble. Run the trimmer at full throttle for a minute, then perform a few test cuts on light grass. Listen for unusual noises—rattling or grinding often signals a misaligned spool or a damaged spring. If everything sounds smooth and the line advances cleanly, the job is complete. Record the date and line type in your maintenance log for future reference.

Comparison Table: Stihl FS 50C vs. Other Models

Tips and Best Practices

• Use only Stihl‑approved .095 in. line for optimal performance.
• Store spare line in a cool, dry place to prevent brittleness.
• Replace the spool annually or after 50 hours of use, whichever comes first.
• Clean the head cavity after each major job to avoid debris buildup.
• When re‑spooling manually, wind the line in the direction indicated by the arrows to maintain proper feed orientation.
• Keep a spare Easy Start cartridge in your tool kit for quick field changes.

Common Mistakes and How to Avoid Them

One frequent error is installing the line backward, which causes the feed to jam. Always follow the molded arrows on the spool. Another mistake is over‑tightening the retaining screw, leading to cracked spool housing; tighten only until resistance is felt. Users sometimes forget to disconnect the spark plug, creating a safety hazard. Finally, using the wrong line diameter—either too thick or too thin—results in poor cutting and excessive engine strain. By double‑checking each step against the owner’s manual, you can avoid these pitfalls and keep your FS 50C running reliably.

Frequently Asked Questions

What line diameter should I use for the Stihl FS 50C?

The manufacturer recommends .095 in. (2.4 mm) nylon line. Using a different diameter can affect feed reliability and engine load.

How often should I replace the Easy Start spool?

Replace the spool at least once per season or after approximately 50 hours of operation, whichever occurs first. Inspect the spool for cracks or worn channels each time you change the line.

Can I use bulk trimmer line instead of the Easy Start cartridge?

Yes, you can wind bulk .095 in. line onto the spool manually, but you must follow the directional arrows and ensure even tension on both strands to maintain proper bump‑feed function.

Why does the line not feed when I tap the head?

Common causes include a tangled line inside the spool, a broken spring retainer, or the spool not fully seated on the drive shaft. Disassemble, inspect, and re‑install following the steps above.

Is it safe to operate the trimmer without the line guard?

No. The guard protects the operator from thrown debris and limits line length to the designed cutting radius. Always keep the guard installed.

Conclusion

Restringing the Stihl FS 50C with the Easy Start spool is a straightforward task when you follow the proper sequence: prepare the correct line, remove the old spool, seat the new cartridge, and verify feed operation. By adhering to the safety precautions, using the recommended .095 in. line, and applying the tips and best practices outlined above, you will maintain consistent cutting performance and extend the life of your trimmer. Remember to inspect the spool regularly, keep the head clean, and replace worn components promptly. With these habits, the question of how to string a Stihl Fs50c weed eater becomes a routine you can complete quickly and confidently, keeping your lawn edges sharp all season long.