How to Restring a Weed Eater Step by Step Guide
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To answer how do I restring a weed eater: first switch the tool off and disconnect its power source. Then open the spool housing, remove the old line, and wind new line onto the spool in the direction the head markings show. The correct line diameter and length are printed on the trimmer head instruction card or in the owner’s manual, so check those before you cut any line. Most of the work takes about ten minutes once you have done it once, and the steps are the same for most string trimmer heads, although the exact clips and tabs vary by brand.
Quick answer
- Turn the trimmer off, remove the battery or unplug it, and keep the blade guard on while you work.
- Use the line diameter and length from the trimmer head instruction card or owner’s manual. STIHL, for example, says to refer to the head instruction card for both.
- Wind the line onto the spool in the direction the arrows or markings on the head indicate, with the two ends of the line even when you start.
- Feed the ends through the eyelets, reassemble the head, and test the feed by tapping the head on the ground while the trimmer is off.
What you need before you start
Gather a new spool or a length of trimmer line that matches your head, a pair of work gloves, and the owner’s manual or the instruction card that came with the head. If you no longer have either, look up the model number on the trimmer and check the manufacturer’s manual library. Line that is too thick can overload the motor, and line that is too thin can break quickly, so matching the diameter the manufacturer lists matters more than the brand of line.
Work on a flat surface where the spool and small parts will not roll away. A tray or a shallow bowl works well for the spring, washers, and the cap screws, because those parts are easy to lose on grass.
Step by step: restringing a bump-feed head
Most home trimmers use a bump-feed head, where a tap on the ground releases a little more line. The steps below cover that design, and they match the general process STIHL describes for its heads: power off, clean the head, and then load line to the length and diameter on the instruction card.
- Power off and disconnect. Turn the trimmer off, remove the battery on cordless models, or unplug a corded model. STIHL’s maintenance guidance says to make sure the equipment is completely powered off before any maintenance. Do not rely on the trigger alone.
- Clean the head. Brush off grass, dirt, and debris from the outside of the head and from the cap. Dirt in the eyelets or around the spool makes reassembly harder and can cause the line to bind.
- Open the head. Most heads have two tabs or a push-and-turn cap. Press the tabs in or turn the cap as the head markings show, then lift off the cover. Keep track of the spring and any washers.
- Remove the old spool. Take out the spool and remove any old line still wound on it. Check the spool for cracks or a worn eyelet before you reuse it.
- Measure the new line. Cut the length the instruction card gives. If the card does not list a length for your model, the owner’s manual is the next place to check. Do not use a length you guessed.
- Find the middle of the line. Fold the line in half so both ends are the same length. Hook the center of the line on the anchor point in the spool, as the spool design shows.
- Wind the line. Wind both strands onto the spool in the direction the arrow on the spool points. Keep the strands side by side and tight, so the spool does not bulge when it spins.
- Feed the ends through the eyelets. Pass each end through the matching eyelet on the spool housing. Leave about the length the manual specifies sticking out of the head, usually a short tail, so the head can feed the line when you tap it.
- Reassemble. Place the spool back in the housing, line up the arrows on the body and the cap, and press or turn the cap until it locks. Some heads need the spring and washers placed in a specific order, so follow the diagram on the instruction card.
- Test the feed. With the trimmer off, tap the head firmly on the ground and confirm that a small length of line feeds out. If nothing comes out, open the head again and check that the line is not trapped under the spool.
Choosing line size and length
The line diameter is the setting that matters most. A heavier line cuts thicker weeds, but it puts more load on the motor and can be harder to feed. A lighter line is easier on the motor, but it wears out faster in dense grass. Use the diameter on the head label or the manual, and do not go up or down a size because a neighbor uses a different one.
The line length matters for balance and feed. Too little line means the head will not reach the grass, and too much line can jam the feed mechanism. If you are unsure, use the length on the instruction card. STIHL’s guidance is to refer to the head instruction card for both diameter and length, and to check the trimmer line chart when you need to choose a line type.
Line type also matters. Round, twisted, and square profiles behave differently in tall grass and near edges. Pick the type that the manual lists for your head rather than the one that is cheapest, because a line the head was not designed for can slip out or feed poorly.
Products with automatic line feed
If you change line often, a head with automatic feed saves time. The listings below mention a feed system in their bullets, so you can compare how each one describes its feed. The listing does not say how often a particular head needs reloading, and the feed description is the only detail from the pack that applies here.
BLACK+DECKER BESTA510 Weed Wacker with Auto Feed
This corded string trimmer’s listing says it uses automatic feed spool technology so the line feeds without bumping. It is a 14-inch cut path with a 6.5-amp motor. The listing states the cutting width is 14 inches and the speed is 8000 rpm. The listing also states a 2 Year Limited Warranty.
ALSO GO 21V Electric Weed Wacker with Auto Line Feed
The listing for this 12-inch cordless model says it has an auto line feed system that extends the line when more is needed, and that the built-in blade trims excess line at startup. The listing states two 2.5Ah batteries and an average life of 40 minutes. The listing states a weight of 5.3 lbs for the tool as shown in its bullets, and it says the model can be rotated to switch between trimming and edging.
DCA 20V 14-inch Cordless String Trimmer
This cordless listing describes a bump auto feed head that releases line with a tap. The listing states one 4.0Ah battery with an average life of 60 minutes, a cutting width of 14 inches, and a weight of about 7.6 lbs with the battery. The listing does not say how many feeds a spool holds, so check the head card for that figure.
Mistakes to avoid
- Winding in the wrong direction. The line can unwind or jam when the head spins if it is wound against the arrow on the spool.
- Using the wrong diameter. A line that is too heavy for the head can stop the feed completely.
- Skipping the power step. Opening a head with the battery in or the cord plugged in is the most common way to get hurt during this job. Remove the battery or unplug the tool first.
- Forgetting the cap screws. Keep the washers and spring in order. A missing washer can let the head come apart under load.
- Mixing parts between heads. Spools from different models often look alike but do not fit the same housing.
When a spool does not feed
If the line will not feed after you reassemble the head, open it and check three things. First, make sure the line is wound tight and evenly on the spool. Second, confirm the two ends came out through the correct eyelets. Third, check that the line is not caught under the spring or washers. A line that is too short will also stop feeding, so if the tails are very short after reassembly, wind a fresh length.
If the head still does not feed, the manual is the next step. The owner’s manual and the manufacturer’s manual library list the head type and the correct procedure for that model, which is more reliable than a general guide.
Safety while you work
Keep the blade guard in place when you test the head, and wear gloves because cut line and the head edges can scratch skin. Do not start the trimmer to check the feed. Tap the head on the ground with the power off, which tests the bump feed without any risk of the head spinning. Store the trimmer with the battery removed when it is not in use.
FAQ
How often should I restring a weed eater?
There is no fixed schedule. Restring when the line runs out, when the feed stops working, or when the line is worn down to a short stub. Heads that bump-feed usually need reloading more often in dense weeds than in soft grass.
Can I use any trimmer line?
Use the diameter and type listed in the manual or on the head instruction card. Line of the right diameter can still fail to feed if the profile is wrong for the head, so check the type as well as the size.
What line length should I load?
Load the length on the head instruction card. If the card is missing, the owner’s manual lists the length for that model. Guessing the length is the most common reason a head stops feeding.
Do I need to remove the head to restring it?
Many heads can be opened without removing them from the shaft. Some models need the head removed first. Check the model’s manual before you take the head apart.
Is it safe to restring a trimmer myself?
Yes, as long as the power is fully off. Remove the battery or unplug the tool before you touch the head. If you are unsure about the spool or the parts, ask a qualified small-engine or power-equipment repair shop, or check the manufacturer’s support line.
What if the spool keeps jamming?
A jam usually means the line is wound unevenly, is too thick for the head, or is caught under the spring. Reopen the head, remove the spool, and rewind the line carefully to the length on the card.
Bottom line
Restringing a weed eater comes down to three checks: power off, the right line diameter and length from the instruction card, and the spool wound in the direction the head markings show. If a head will not feed after reassembly, reopen it and check the winding and the eyelets before you buy a new head. For more background on choosing a trimmer, read Top 10 Battery Powered Weed Eaters: 6 Real Picks Compared, and for a related power-tool setup topic, see Best Ryobi ONE+ String Trimmers Compared.
