Your Stihl Trimmer Line Is Worn Out. Here’s the Fix
You’re halfway through edging the driveway when your Stihl trimmer starts making that awful slapping sound. Instead of a clean cut, it’s just whipping the grass. The line is worn down to a nub, and your work grinds to a halt.
Knowing how to change the line on your Stihl trimmer is a basic but essential skill for any homeowner. It’s not hard, but doing it wrong can lead to frustration, wasted line, or even a jammed trimmer head. This guide walks you through the entire process, from identifying the right line to winding it perfectly for a smooth restart.
What You Need Before You Start
Gathering the right tools and materials makes the job faster and safer. You don’t need much.
– Replacement Trimmer Line: This is the most important part. Check your Stihl trimmer’s manual for the correct diameter (common sizes are .080″, .095″, or .105″). Using the wrong size can cause poor performance or head damage.
– Scissors or a Sharp Knife: For cutting the line to the proper length.
– Safety Gloves: To protect your hands from sharp edges and hot surfaces if the trimmer was recently used.
– Safety Glasses: Always a good idea when dealing with any power tool maintenance.
– A Clean Workspace: A flat bench or table is ideal.
Step-by-Step Guide to Changing the Line
The process varies slightly depending on whether you have a bump-feed head or a fixed-line head. Most common Stihl homeowner trimmers use a bump-feed system. We’ll cover both.
For Bump-Feed Trimmer Heads (Most Common)
This is the head where you tap it on the ground to advance fresh line. The goal is to remove the spool, wind new line onto it, and reassemble.
1. Disconnect the Spark Plug. This is the cardinal rule of safety. Locate the spark plug wire and pull it off the plug. This ensures the trimmer cannot accidentally start while your fingers are near the head.
2. Remove the Trimmer Head. Press down on the retainer at the center of the head (often a button or cap) and unscrew the entire head assembly from the drive shaft. It usually turns clockwise to loosen. Some models have a locking hole for a pin or Allen key to hold the shaft.
3. Open the Head. Hold the head with the bump button facing down. Depress the tabs on the sides of the head and lift off the cover to reveal the spool inside.
4. Remove and Clean the Spool. Take out the spool. This is a good time to clear out any old, tangled line fragments or grass clippings from inside the head housing.
5. Prepare the New Line. Cut two lengths of line, each about 15-25 feet long, depending on your spool’s capacity. Check the spool for an arrow indicating the winding direction.
6. Load the Spool. Find the two small holes or notches on the spool. Insert one end of a line piece into a hole, leaving about 6 inches sticking out. Wind the line tightly and evenly onto that half of the spool, following the directional arrow. Repeat for the second line in the other hole on the opposite side of the spool.
7. Secure the Lines. Most spools have small clips or slots near the exit eyes. Hook the ends of your lines into these to prevent them from unwinding during assembly.
8. Reassemble the Head. Place the loaded spool back into the lower housing. Feed the two line ends out through the two exit holes (or eyelets) on the head. Pull them until they are even. Snap the cover back on until it clicks securely.
9. Reattach the Head. Screw the head back onto the drive shaft. It typically tightens counter-clockwise. Reconnect the spark plug wire.
10. Advance the Line. With the trimmer on a safe surface, start the engine. Tap the head firmly on the ground to bump out the fresh line until it reaches the proper cutting length, about the diameter of the guard.
For Fixed-Line or Manual Heads
These are less common but simpler. The head doesn’t open; you feed new line directly through an eyelet.
1. Follow the same safety step: disconnect the spark plug.
2. Locate the line hole on the side of the trimmer head.
3. Cut a single, longer piece of line (check manual for length).
4. Feed one end of the line into the hole and push it through until an equal amount protrudes from both sides of the head.
5. Manually wind the head (or use the starter) to wrap the line around the spool inside until the ends are short, even, and ready to cut.
Choosing the Right Trimmer Line
Not all line is created equal. Using the correct type improves performance and durability.
– Diameter: Never use a line thicker than your trimmer is rated for. It can overload the engine and damage the drive system. Thinner line cuts tender grass well; thicker line is for tough weeds and brambles.
– Shape: Round line is standard and economical. Square, star, or serrated line offers a more aggressive cut for thick vegetation but can wear faster.
– Material: Most line is nylon. Look for lines labeled “professional” or “high-impact” for better resistance to breaking and abrasion.
Common Problems and Troubleshooting
Even with careful winding, you might run into issues. Here’s how to solve them.
The Line Won’t Advance When You Bump
This usually means the line is wound in the wrong direction on the spool. The line must be wound opposite the direction the head spins. Take the spool out and re-wind it, ensuring you follow the directional arrow molded into the spool.
The Line Breaks Constantly
Frequent breakage is frustrating. Common causes include hitting rocks, fences, or concrete. But if it’s breaking too easily, check your line. Old, sun-damaged line becomes brittle. Ensure you’re using a diameter your trimmer can handle without strain. Also, avoid letting the line get too long, as the extra length creates more centrifugal force and stress.
The Head Jams or Won’t Spin
If the head locks up, stop immediately. First, check for a massive tangle of line wrapped around the spool or drive shaft—this is often caused by incorrect winding or a missing spring inside the head. Disassemble, clear all debris, and reassemble correctly. Also, ensure the head is screwed on tightly.
Uneven Line Wear
If one line wears down much faster than the other, the likely culprit is an uneven length. When you bump the head, the longer line hits the ground first and takes all the wear. During assembly, always pull both lines out evenly before snapping the cover shut.
Pro Tips for Easier Maintenance
A few simple habits will keep your trimmer running smoothly all season.
– Pre-Cut Several Sets of Line. During the off-season, cut and wind a few extra spools. Store them in a zip-top bag. When you run out, you can swap the entire spool in under a minute.
– Keep the Head Clean. After each use, tap out any debris and occasionally rinse the head (with the spark plug disconnected) to prevent grass and mud from gumming up the mechanism.
– Don’t Force the Bump. A firm tap on flat ground is all that’s needed. Slamming the head on concrete can damage the advance mechanism and break the line prematurely.
– Store Line Properly. Keep unused trimmer line in a cool, dry place out of direct sunlight to prevent it from becoming brittle.
When to Consider a New Trimmer Head
If you’re constantly fighting jams or the advance mechanism is broken, it might be more cost-effective to replace the entire head. Stihl offers easy-replace heads that use pre-wound spools you simply click in, eliminating winding altogether. For heavy users, this can be a worthwhile upgrade for convenience.
Get Back to a Perfect Edge
Changing the line on your Stihl trimmer is a straightforward task that saves you time and money. By following these steps—prioritizing safety, winding the spool correctly, and using the right line—you’ll eliminate a common point of frustration.
The next time your trimmer starts struggling, you won’t have to stop your yard work. You’ll have the confidence to reload it quickly and get back to creating those crisp, clean lines that define a well-kept property. Grab your line and gloves, and give it a try.
