To add string to a weed eater, first disconnect the spark plug (or remove the battery) for safety. Remove the trimmer head, take out the spool, and cut a fresh length of trimmer line (typically 10–20 feet depending on the head type). Insert one end into the spool’s anchor hole, wind the line evenly in the direction indicated by arrows, leave about 6 inches of line protruding from each eyelet, then reassemble the head and test the feed mechanism. This process applies to most string trimmers, though the exact steps may vary slightly based on the head design.
Preparation and Safety
Before you begin adding string to your weed eater, safety should be your top priority. Even though you are not operating the tool, the cutting head can be under tension, and accidental starting could cause injury. Always disconnect the spark plug wire on gas-powered models to prevent the engine from firing. For battery-powered units, remove the battery pack entirely. This ensures that the trimmer cannot start while you are handling the head and spool.
Gather the necessary tools and materials. You will need the correct replacement trimmer line, which should match the diameter recommended by the manufacturer. Common diameters include 0.065, 0.080, 0.095, and 0.105 inches, but always check your owner’s manual. You may also need a screwdriver or a specialized tool to open the trimmer head, though many modern heads feature a push-tab or twist-off design that requires no tools. Wearing gloves is advisable, as the line can be stiff and the head may have sharp edges. Have a tape measure or ruler handy to cut the line to the proper length.
Work in a clean, well-lit area, preferably on a workbench or flat surface. If you are restringing an existing head, take a moment to inspect the spool and the head for any debris, cracks, or wear. Clean out any old line fragments and dirt to ensure smooth operation. Knowing your trimmer model and having the manual nearby can help you identify the specific procedure for your head type, as some are more complex than others.
Opening the Trimmer Head and Removing the Spool
With safety precautions in place, the next step is to access the spool where the line is stored. Trimmer heads come in several designs, but the most common are bump-feed, fixed-line, and automatic-feed models. The method for opening the head varies accordingly. For many bump-feed heads, you will find two tabs or buttons on the sides of the head. Press these inward while pulling the outer cover downward. This releases the cover and exposes the spool. Some heads require you to twist the cover counterclockwise to unscrew it. If you encounter resistance, double-check that you are twisting in the correct direction, as some threads are reversed.
On fixed-line heads, the design is often simpler. These heads typically have a cap that you unscrew or a retaining ring that you remove with a screwdriver. Once the cover is off, the spool should lift out easily. If the spool is stuck, gently tap the side of the head or use a small pry tool, but be careful not to damage the plastic. In some cases, you may need to remove a central bolt to free the spool, but this is less common on consumer-grade trimmers.
After removing the spool, take note of any old line that remains. Remove all remnants, as leftover pieces can interfere with the new line. Examine the spool for arrows or directional indicators that show the winding direction. These arrows are crucial for correct installation. Also, identify the anchor holes or slots where the ends of the line will be inserted. Some spools have a single continuous channel with a central anchor, while others have separate compartments for each line end. If your spool has a spring or other components, keep them organized so they can be reassembled correctly.
Measuring and Cutting the New Line
Choosing the right trimmer line is essential for effective cutting and to avoid damaging your weed eater. The diameter must match the specification for your model; using a line that is too thick can overload the engine or motor, cause excessive vibration, and possibly break the trimmer head. Conversely, a line that is too thin will break frequently and cut poorly. The owner’s manual is the most reliable source for the correct diameter. If you do not have the manual, you can often find the information on a label on the trimmer or by looking up the model online.
Once you have the correct line, you need to cut it to the appropriate length. Most trimmers require between 10 and 20 feet of line, depending on the size of the spool. A typical spool holds about 15 to 25 feet in total, but some larger commercial models may hold more. A good rule of thumb is to use the same length as the old line you removed, or to follow the measurement provided in your manual. If you are unsure, start with 20 feet; you can always trim off excess if it does not fit.
When cutting the line, use sharp scissors or a utility knife to get a clean, straight cut. Avoid using dull blades, as they can crush the line and make it difficult to thread. Many lines have a specific shape—round, twisted, square, or star-shaped—each offering different cutting characteristics. While round line is common and versatile, twisted or multi-edged lines may last longer and cut through thick grass more efficiently. However, these claims vary by brand, and it is best to stick with what your trimmer manufacturer recommends for consistent performance.
Threading the Line onto the Spool
With the line cut to length, you are ready to thread it onto the spool. This step requires attention to the winding direction. Look for the arrows molded into the spool—these indicate the direction you must wind the line so that it feeds correctly during operation. Typically, the line winds in the same direction as the arrow, which usually matches the rotation of the cutting head. If you wind in the wrong direction, the line will not feed properly, and the trimmer may not cut effectively.
Begin by inserting one end of the line into the anchor hole on the spool. Some spools have two anchor holes, one for each end of a single continuous line, while others have a central slot where you place the middle of the line. For a two-hole design, push the end through the hole until it comes out the other side, then pull it until the line is seated securely. For a central slot, fold the line in half and place the bend into the slot, ensuring it locks in place. Once anchored, start winding the line onto the spool in the direction of the arrow. Keep tension on the line to ensure it lays flat and evenly, without crossing over itself.
Continue winding until only about 6 inches of line remains on each end. If your spool has two separate ends, you will need to wind both sides, typically by placing the line in a groove and winding each half separately. Many spools have a divider that separates the two sections. Make sure the line is distributed evenly across the spool to prevent jamming. After winding, insert each free end into the corresponding eyelet or slot on the spool cover or the head, leaving the 6-inch tails exposed. These tails will be the cutting portions when the trimmer is reassembled.
Reassembling and Testing
Now that the line is properly wound and the ends are protruding from the eyelets, it is time to put the trimmer head back together. Place the spool back into the housing, making sure it sits flush and that the spring (if present) is correctly positioned. Reattach the outer cover by aligning any tabs or slots. For bump-feed heads, you will typically press the cover down firmly until it clicks into place. For screw-on caps, turn them clockwise until they are snug, but do not overtighten, as that can strip the threads or make future removal difficult.
After reassembly, test the feed mechanism before using the trimmer on your lawn. Reconnect the spark plug or install the battery. Turn the trimmer on and let it run for a few seconds. Then, gently tap the bump-feed knob on the ground while the head is spinning—this should release additional line if the mechanism is functioning correctly. For fixed-line heads, you may need to manually pull the line to extend it, or the line will advance automatically as the head rotates. If the line does not feed, check that you have not wound it too tightly or that the ends are not caught in the housing.
If the line fails to feed despite correct assembly, the issue may be with the winding direction or the anchor points. Disassemble and check that the line is seated in the anchor holes properly and that the winding matches the arrows. Also, ensure that the line is not twisted around itself inside the spool. With a little patience, you should be able to get the line feeding smoothly. Remember to always keep your hands clear of the cutting head when the trimmer is running, and wear appropriate eye protection during operation.
Bump-Feed vs. Fixed-Line Heads
Understanding the differences between bump-feed and fixed-line heads can save you time and frustration. Bump-feed heads are the most common on consumer trimmers. They allow you to advance the line by tapping the bottom of the head on the ground while the trimmer is running. This action releases a mechanism that lets out a little more line. When restringing a bump-feed head, the winding process is straightforward but must follow the directional arrows precisely. The spool usually has two separate compartments for the two line ends, and you wind each section individually. The bump-feed mechanism relies on a spring and a ratchet; when you tap, the spring pushes the spool downward, allowing the line to unwind slightly. This design is popular because it lets you control the line length without stopping.
Fixed-line heads, on the other hand, do not have a bump-feed feature. Instead, the line is either pre-cut to a specific length and replaced as a unit, or the head uses a manual feed where you pull the line out to the desired length before cutting. Some fixed-line heads have a single-piece spool that you wind completely, and the line is advanced by the centrifugal force of the spinning head or by manually pulling it. Restringing a fixed-line head is often simpler because there is no spring mechanism, but you may need to cut the line to exact lengths or use pre-measured replacement spools. Some models have a quick-load feature that eliminates winding altogether—you simply push the line through a hole and turn the head to wind it automatically.
Regardless of the head type, always consult your owner’s manual for the manufacturer’s recommended procedure. Using a line diameter thicker than recommended can damage the trimmer head, and certain line shapes may last longer than round line, but this depends on the cutting conditions. If you are unsure which type of head you have, look for a bump knob on the bottom—if it has a spring-loaded bump knob, it is bump-feed; if the bottom is flat and smooth, it is likely fixed-line or automatic-feed. With practice, restringing your weed eater becomes a quick and routine maintenance task that keeps your trimmer performing at its best.
