To replace the line on a string trimmer, first ensure the trimmer is powered off and disconnected from its power source—either by unplugging the cord, removing the battery, or disconnecting the spark plug wire. Remove the spool cap from the trimmer head by pressing the release tabs or unscrewing it. Measure and cut the trimmer line according to your manufacturer’s specifications. For bump-feed heads, anchor the line into the spool and wind it tightly in the direction of the arrows. Finally, thread the ends through the eyelets, reattach the cap, and test the feed mechanism.
Understanding Your String Trimmer Head Type
Before attempting to replace your trimmer line, it is essential to identify the type of trimmer head your machine uses. Using the wrong method can cause the line to tangle or fail to feed during operation.
What is a bump-feed trimmer head?
A bump-feed head is the most common design. It features a mechanism that releases more line when the user taps the bottom of the trimmer head against the ground while the engine or motor is running. These heads contain an internal spool that must be wound with new line periodically.
What is a fixed-line or speed-feed trimmer head?
Fixed-line heads do not use a spool; instead, you insert pre-cut lengths of line directly into the head. Speed-feed heads are a variation that allows you to thread the line through the head and crank a knob to wind it internally without disassembling the unit. Always check your specific trimmer model to determine if it supports these features.
How do I identify which type of head my trimmer has?
Inspect the trimmer head for a central button or knob on the bottom. If you see a button that moves when pressed, it is likely a bump-feed head. If the head has small holes or slots on the side and no central button, it is likely a fixed-line head. Consult your owner’s manual if you are unsure, as the manual will provide specific instructions for your model’s maintenance.
Step-by-Step Guide to Replacing Trimmer Line
Following a systematic approach will help ensure the line feeds correctly and does not tangle inside the housing.
How do I remove the old spool and line?
With the trimmer safely powered down, locate the release tabs on the sides of the trimmer head. Press them simultaneously to pop off the spool cap. Remove the spool by pulling it straight out. If the old line is tangled or fused, clear it out completely. Inspect the eyelets—the small holes where the line exits—to ensure they are not clogged with debris.
How do I measure and cut the correct length of new line?
The length and gauge (thickness) of the line are critical. Use only the line diameter recommended by the manufacturer, as a line that is too thick may jam the head, while one that is too thin may break prematurely. Check your manual for the recommended length, which typically ranges from 10 to 25 feet depending on the spool size.
How do I wind the new line onto the spool correctly?
Most spools have a divider in the middle to keep two strands of line separate. Insert the ends of the line into the anchor points on the spool. Wind the line tightly and evenly in the direction indicated by the arrows molded into the spool. Avoid overlapping the lines, as this can prevent the bump-feed mechanism from working properly.
How do I reassemble the trimmer head and feed the line?
Once the spool is wound, leave a few inches of line protruding from each side. Thread these ends through the eyelets in the trimmer head housing. Place the spool back into the head, ensuring the spring is properly seated. Snap the spool cap back into place until it clicks. Pull the ends of the line to ensure they move freely, then trim the excess if necessary.
Important Considerations Before You Start
Safety and precision are paramount when performing routine maintenance on outdoor power equipment.
Why is it critical to check my owner’s manual for the correct line gauge?
The line gauge determines the cutting performance and the stress placed on the trimmer’s motor. Using a gauge thicker than the manufacturer’s recommendation can cause the motor to overheat or the feed mechanism to seize. Always refer to the manual to ensure compatibility.
What safety steps should I take before beginning?
Never perform maintenance while the trimmer is connected to a power source. For gas trimmers, wait for the engine to cool completely to avoid burns. For electric models, ensure the battery is removed or the cord is unplugged to prevent accidental activation. Wear work gloves to protect your hands from sharp line ends or rough plastic edges on the trimmer head.
When should I consider replacing the entire spool head instead of just the line?
If the plastic housing of the head is cracked, the eyelets are worn down, or the bump-feed mechanism no longer clicks or releases line, you may need to replace the entire trimmer head assembly. If you are unsure about the integrity of the parts, consult a professional technician to ensure the trimmer remains safe to operate.
