The line of your string trimmer refuses to come out, gets stuck in the spool, or breaks at the first contact with a border. This scenario recurs every season for most users of trimmers. The main cause is not the normal wear of the line, but a faulty winding or a misunderstood feeding system. Knowing how to diagnose the type of head on your machine radically changes the speed at which you can resume cutting.
Line stuck in the spool: the mechanical causes that are often overlooked
Before pulling on the line or hitting the head on the ground, it is important to understand why the blockage occurs. In most cases, the line has welded itself to itself inside the spool. This phenomenon occurs when the nylon heats up due to rapid rotation, then cools while remaining compressed against neighboring coils.
A winding that is too tight or loose exacerbates the problem. If the coils overlap instead of lying side by side, the line gets stuck at the first use. Field reports vary on this point: some users never experience a blockage with the same machine that a neighbor suffers from every week. The difference almost always comes down to the winding method.
Another common cause: a piece of vegetation or dirt infiltrates through the exit eyelets and blocks the rotation of the line in the head. A quick cleaning of the spool and the housing, by removing the lower cover, is often enough to resolve the issue without changing the line.
To understand how to get the line out of the string trimmer, you must first identify the type of head mounted on your device, as the handling differs completely from one system to another.
Ground contact head, Tap and Go, quick reloading: adapting the gesture to the system
Three main families of heads coexist on the market, and each requires a specific technique for extending the line.
Ground contact head (classic Tap and Go)
This is the most common system on consumer string trimmers. By pressing the head against the ground while the motor is running, a spring mechanism releases a few centimeters of line. The gesture must be brief and firm. A prolonged press unwinds too much line, which overloads the motor and causes an almost immediate breakage.
On most machines, a knife fixed to the housing automatically cuts the excess line to the correct length. If this knife is dull or broken, the line remains too long and the head vibrates abnormally. Check its condition at least once a season.
Quick reloading head without disassembly
Recent models, particularly from Husqvarna, offer heads where you simply insert the line across the spool and then rewind it by turning the head manually, without opening the cover. This system significantly reduces the risks of improper winding, which remains the major cause of line blockage.
- Cut a section of line to the length recommended by the manufacturer, fold it in half, and then insert the loop into the central slot of the spool.
- Turn the cover in the direction indicated by the arrow engraved on the head to wind the two strands evenly, without overlapping.
- Let the ends protrude through the exit eyelets before putting the head back on the shaft.
Automatic head (AutoCut, SuperCut, DuroCut)
The AutoCut and SuperCut heads from Stihl, or their equivalents from other brands, release the line through a centrifugal system: the force of rotation pushes the line outward with each acceleration. No ground contact is necessary. However, if the line is poorly wound or if the spool is overloaded, the centrifugal system will no longer work and the line remains stuck.
The DuroCut head, on the other hand, uses short segments of line inserted individually, which eliminates the winding problem. This system is particularly suitable for work on uneven terrain where breakages are frequent.
Choosing nylon line: diameter and profile influence the output
The diameter of the line must correspond to the range indicated by the manufacturer of your string trimmer. A line that is too thick does not pass through the exit eyelets. A line that is too thin breaks more quickly and winds unevenly in the spool.
Twisted or profiled lines reduce noise and vibrations compared to classic round lines. This comfort gain also has a mechanical effect: less vibration in the head means less micro-movement of the line inside the spool, leading to more regular unwinding and fewer blockages.
For areas close to homes or in semi-urban environments, a twisted line of a diameter suitable for your machine represents a good compromise between cutting efficiency and noise reduction. The available data does not allow for precise quantification of the sound gain, but the difference is noticeable to the ear within the first few minutes of use.
Maintenance of the spool and housing: actions that prevent recurring blockages
A string trimmer with poorly dispensing line does not necessarily need a new part. A few regular maintenance actions eliminate the vast majority of problems.
- After each use, remove the spool and blow out the plant debris stuck in the housing. A simple dry brush will also do the trick.
- Check that the return spring of the Tap and Go head is not deformed or clogged. A tired spring prevents the mechanism from releasing the line during ground contact.
- Store the replacement nylon line in a cool, dark place. Nylon becomes brittle with age, especially if exposed to UV light. Some users soak the line in water for a few hours before loading it to restore its flexibility.
- Check the cutting knife fixed to the housing at least once a season. If it is chipped, replace it: a poorly cut line fatigues the motor and causes excessive vibrations.
A neat winding and a clean housing resolve most line dispensing issues. Recent machines with quick reloading heads simplify this step, but do not eliminate the need for regular cleaning. Before suspecting an expensive mechanical defect, start by opening the head, cleaning, and rewinding correctly: in most cases, the line comes out again without difficulty.