How to Change the String on a Weed Wacker: Step-by-Step Guide for Any Trimmer

What is the direct answer for changing the string on a weed wacker?

To change the string on a weed wacker, you must first turn off and disconnect the trimmer. Next, remove the trimmer head or spool cover to access the old line. Take out any remaining old line and clean the spool. Cut a new piece of replacement line to the manufacturer’s recommended length, typically between 10 and 25 feet. Wind this new line onto the spool in the direction indicated by arrows, maintaining firm tension. Leave 6 to 12 inches of line extending from each eyelet, then reassemble the head and test the feed mechanism.

Understanding Your Trimmer Head Type

Before you begin, it is critical to identify the type of trimmer head on your weed wacker. The restringing method varies significantly between designs. The most common types are bump feed, fixed line, and automatic feed.

• Bump Feed Head: This is the most prevalent type for residential use. It features a spool of line inside a housing. You “bump” the head on the ground during operation to feed more line. Restringing involves winding line onto an internal spool.
• Fixed Line Head: This head has pre-cut lengths of line that are inserted into specific slots or holes. There is no internal spool to wind. Restringing is a matter of cutting new line segments and securing them in place.
• Automatic Feed Head: Also called a “power feed” or “easy feed,” this head automatically advances line when the motor is running or when a specific button is pressed. The restringing process can be more complex and often requires specific line types or spool cartridges.

To identify your head type, look for a bump knob on the bottom (bump feed), multiple line ports around the perimeter (fixed line), or a button on the side of the head (automatic feed). Always consult your owner’s manual for the definitive method for your specific model.

Tools and Materials You’ll Need

Gathering the right supplies beforehand ensures a smooth process. You will need:

• Replacement Trimmer Line: Use the diameter specified in your trimmer’s manual. Common diameters are 0.065 inch, 0.080 inch, and 0.095 inch. Thicker line is for more powerful trimmers. Line material is usually nylon.
• Scissors or Line Cutters: For cutting the new line to length.
• Pliers (Optional): Can help grip and remove stubborn old line.
• Screwdriver or Socket Set (If Needed): Some trimmer heads require a tool to remove a retaining bolt or screw.
• Clean Cloth: For wiping debris from the spool area.

Check your trimmer’s manual or the spool itself for markings that indicate the maximum line diameter and length it can hold.

Step-by-Step Guide to Restringing a Bump-Feed Trimmer Head

This is the most common procedure. Follow these steps carefully.

Step 1: Prepare the Trimmer Safely

Turn off the trimmer and disconnect the spark plug wire (for gas models) or remove the battery (for electric models). This prevents accidental startup. Allow the engine to cool if it was recently running.

Step 2: Remove the Trimmer Head or Spool Cover

Depending on your model, you may need to press tabs on the side of the head to release the spool, or unscrew a bump knob. Some heads require you to hold the outer housing and turn the inner spool counter-clockwise. Refer to your manual. Once released, carefully lift out the spool.

Step 3: Remove Old Line and Clean the Spool

Pull out any remaining old line. Clean away grass clippings, dirt, and debris from the spool and the inside of the head housing. Ensure the line feed channels are clear.

Step 4: Cut and Prepare New Line

Cut a new length of line. A good rule of thumb is 10 to 15 feet for residential trimmers, but check your manual. If the spool has two separate winding sections, you will need two equal lengths of line.

Step 5: Wind the New Line onto the Spool

Look for arrows or text on the spool indicating the winding direction. Secure the starting end of the line in the anchor slot or hole at the center of the spool. Wind the line tightly and evenly in the direction shown. Maintain firm, consistent tension to prevent tangles. If your spool has two lines, wind each one onto its designated half, keeping them separate.

Step 6: Secure the Line Ends

Once wound, secure the line ends into the notches or clips on the edge of the spool. Leave 6 to 12 inches of line extending from each eyelet. This length is what you will initially feed through the head.

Step 7: Reassemble the Head

Carefully place the wound spool back into the trimmer head housing. Align it correctly so it seats properly. Reattach the bump knob or cover, ensuring any tabs click into place or screws are tightened. Pull the line ends to ensure they feed freely through the eyelets.

Step 8: Test the Feed Mechanism

Reconnect the power source. With the trimmer held safely off the ground, start it and gently tap the bump knob on a hard surface (like concrete) to test if the line feeds. If it doesn’t, disassemble and check that the line is wound in the correct direction and is not tangled.

Restringing Other Trimmer Head Types

The process differs for other designs.

• Fixed-Line Head: Remove the old line segments. Cut new line to the length specified for your head (often 10-14 inches per side). Insert the center of the line into the designated slot or wrap it around the center post, then thread each end through the outer eyelets and secure them in the locking notches.
• Automatic-Feed Head: These often use pre-wound spool cartridges or require a specific winding pattern. You may need to remove a cap, insert a new cartridge, and ensure it clicks into place. If winding manually, follow the precise instructions in your manual, as incorrect winding will prevent automatic feeding.

Troubleshooting Common Issues

If you encounter problems after restringing, here are common solutions:

• Line Won’t Feed: The line is likely wound in the wrong direction. Disassemble and rewind it according to the arrows. Also, check that the line is not tangled on the spool.
• Line Tangles or Welds Together: This is often caused by insufficient tension during winding. The line gets too hot from friction and melts together. Disassemble, clean the spool, and rewind with tighter, more even tension.
• Line Breaks Immediately: You may be using a line diameter that is too thin for your trimmer’s power, or the line is hitting a hard object like a fence. Ensure you’re using the recommended diameter. Also, check that the line is feeding smoothly and not catching on the housing.
• Head Won’t Reassemble: The spool is likely not seated correctly. Ensure it is aligned with any tabs or guides inside the housing before attempting to secure the cover.

Maintenance Tips for Longer Line Life

To reduce how often you need to restring:

• Use the Correct Line: Always use the diameter and type recommended for your trimmer model.
• Trim at the Right Speed: Running the trimmer at full throttle when not cutting can cause unnecessary line wear.
• Avoid Hard Obstacles: Line breaks quickly on concrete, rocks, and fences. Trim carefully around these areas.
• Store Properly: Store your trimmer in a dry place. Extreme heat or cold can degrade nylon line over time.

Frequently Asked Questions

What type of replacement line should I buy for my weed wacker?

You should buy the line diameter specified in your trimmer’s owner’s manual or on the spool itself. Common residential diameters are 0.065 to 0.080 inch. Commercial or heavy-duty trimmers may use 0.095 inch or thicker. The material is typically nylon.

How do I know which direction to wind the line on the spool?

Look for arrows or text printed directly on the spool or inside the trimmer head housing. These indicators show the correct winding direction. Winding against this direction will prevent the line from feeding properly.

Can I use any brand of trimmer line?

Yes, as long as the line diameter and shape (round, square, etc.) match your trimmer’s specifications. However, always prioritize the diameter requirement for safety and performance.

Why does my trimmer line keep breaking so quickly?

Common causes include using a line diameter that is too thin for your trimmer’s power, frequently hitting hard surfaces like concrete or rocks, or using low-quality line. Ensure you are using the manufacturer-recommended diameter and try to avoid contact with hard obstacles.