How to Replace a Lawnmower Bobbin

I want to devote today’s article to the sore topic of summer residents and gardeners of the entire post-Soviet space “How to refill a fishing line into a trimmer.” Not many trimmer manufacturers answer this question in their operating instructions. Therefore, it is difficult for ordinary gardeners to figure out how to do this correctly.

I want to start with a brief description of the technical characteristics of the trimmers.

So, trimmers are electric and gasoline. The cutting element of the trimmers can be a fishing line and a knife. The fishing line is ordinary, four. pentahedral and intertwined (in the form of a pigtail). Knives come in 2, 3 and four blade blades. Knives are also plastic and metal.

The feed system of the fishing line from the trimmer is manual, semi-automatic and automatic.

Development engineers who create new models of trimmers clearly calculate the diameter (thickness) of the fishing line and the number of knife blades according to the power of the trimmers. Otherwise, the engine is overloaded, which as a result leads to its breakdown. And this is an additional and significant cost.

Today on the market are trimmers:

With one nozzle. only fishing line.
With two nozzles. fishing line and three-four-blade knife.
With one nozzle. only a three-four-blade knife.

Our Kulibins long ago learned to improve any mechanisms. So, for example, some gardeners make successful, in their opinion, replacing the fishing line with a metal cable, or fishing line. But at the same time they do not think about the safety of their and their loved ones, because, as a cable with the power of a working trimmer, it can easily break out and not only injure the mower and others, but leave it crippled for life. Using fishing line can and gives a better effect, I have never personally tried it than fishing line for trimmer, but this work has a number of inconveniences: when it comes into contact with solid objects it dissolves or can simply be pulled out of the reel without limit.

So what is called closer to the topic. I give an example of how to fill a fishing line into a trimmer (BOSCH Art 30 trimmer). Everything is very simple. We started.

After you have chosen the fishing line for refueling, you need to cut off the necessary amount of fishing line, because all the fishing line in the skein is not wound into a reel.

Cut off and start winding.

Remove the coil and the protective cover from the coil.

They took off. We fix one end of the fishing line into the gap and carefully and evenly wind the fishing line.

The amount of fishing line should be such that the protective cover of the reel closes and the line on the reel unwinds itself a little.

The second end of the fishing line is planted in the hole on the protective cover.

Next, take the coil and the protective cover of the coil. We sink the end of the fishing line from the reel into the metal hole on the protective cover of the reel. Tighten the fishing line a little.

We put it all on the trimmer. Turn the coil clockwise until it clicks.

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Secured. Now connect the trimmer to the network. We put the trimmer in the starting position for the job. Turn on the trimmer. The excess length of the fishing line will be cut off on the cutting blade.

Trimmer Coil

That’s all starting work.

You can watch the video

A little tip. Make sure that the fishing line does not come into contact with solid objects when cutting. With this contact, the fishing line will be cut. And since, in this trimmer, the fishing line is not fed automatically, then you have to stop the work each time, remove the reel and re-release the fishing line.

In my trimmer, in addition to the standard line for mowing the lawn, there is still provided a thick fishing line for mowing coarse weeds. It has the shape of a pigtail, i.e. Three fishing lines are tightly intertwined. Such a fishing line has its own reel.

Thick fishing line

It is stored at the top of the trimmer body.

Spare coil storage space

Installing such a fishing line into the reel is very simple. according to the internal circuit inside the reel. We insert the center of the fishing line with a metal mount at the top of the reel, and draw the ends of the fishing line along the grooves and bring it out.

Reinforced Fishing Line

Such a coil is attached to the trimmer as well as a reel with ordinary fishing line.

The trimmer, whether it is gasoline or electric, is the only right solution for mowing grass in hard-to-reach places that cannot be handled by a wheeled lawnmower. As a cutting tool, trimmers use metal knives or a special fishing line, which is tucked into the trimmer coil. But, unfortunately, the trimmer heads during operation over time become unusable. Some malfunctions can be eliminated with your own hands, and some require a complete replacement of the mowing head.

Trimmer Coil Device

Mowing heads for trimmers come in many designs. both simple and complex. The picture below shows semi-automatic trimmer head from the Husqvarna lawn mowers (Husqvarna) disassembled.

How to Replace a Lawnmower Bobbin

This type of head is present in the configuration of most lawnmowers and trimmers, such as Stihl (Stihl), Patriot (Patriot), Champion (Champion), Bosch (Bosch), Huter (Huter) and others. The mower head is quite simple. It consists of the following details:

Video: How to Replace a Lawnmower Bobbin


  • mowing head base;
  • button for semi-automatic cord feeding;
  • a bobbin (reel) into which the fishing line is refueled;
  • spring;
  • eyes. through them the fishing line comes out;
  • trimmer head cover;
  • fishing line (cord).

There are also simpler trimmer heads shown in the following photo.

All these attachments do not allow changing the length of the fishing line in semi-automatic mode (after pressing the button). In the event of a break in the cord, you have to stop the mower and change it manually.

Basic coil faults

Trimmer users and lawn mowers often encounter a problem with a semi-automatic mowing head. Coil malfunctions can be as follows:

  • the fishing line does not automatically extend;
  • the cord spontaneously exits the coil.

The fishing line does not automatically extend

If the line does not lengthen with a light touch of the trimmer coil button on the ground, the reasons for this may be as follows.

Option 1. a bite occurred, i.e. clamping cord between turns. This problem usually occurs if the user wound the fishing line on the reel unevenly, with the intersection of turns, or wound it with insufficient tension. In the latter case, when the mowing head rotates at high speeds under the influence of centrifugal force, the cord begins to drag out, as a result of which it is possible to twist the fishing line. To fix the problem, you will have to disassemble the coil on the trimmer and rewind the cord correctly, that is, in even turns with good tension.

Option 2. too short ends protrude from the head. The fishing line may not come out when it hits the ground, if its ends protruding from the head are of insufficient length (short). In this case, centrifugal force is not enough to stretch the line. Therefore, it is necessary to stop the unit (turn off the engine or disconnect the trimmer from the mains) and pull out the fishing line manually by first pressing the button.

Option 3. fishing line soldered inside the mowing head. This causes the coil to stop and not spin when the button is pressed. Basically, this happens for several reasons: poor quality of the cord, overheating of the coil during continuous operation of the unit, impact of fishing line on solid objects.

  1. In the first case, the cord of third-party manufacturers can be made of low-quality and low-melting materials that do not withstand mechanical and thermal stress. Therefore, preference should be given to “branded” fishing lines.
  2. But, if you nevertheless acquired a fishing line of unknown quality, and it often gets soldered during operation, then you can follow the example of some users who, after refueling the cord into a coil, moisten it either silicone grease (from spray can), or mineral oil. This procedure greatly reduces the likelihood of soldering between each other turns of fishing line.
  3. Also, the fishing line can be soldered if during mowing it hits a solid object (stone, fence, dry branch, etc.). As a result of this, it stretches a little and is pulled back into the head at high speed. The cord heats up due to friction, and its coils stick together. The only thing that can be done to eliminate this malfunction is to open the trimmer coil and rewind the fishing line.

Cord spontaneously lengthens

There are situations when the trimmer user notices very fast consumption of fishing line. However, he never hit a button on the ground to lengthen the fishing line. The reason that the fishing line spontaneously lengthens, cutting off a special knife on the casing of the device, can serve lack of spring in the mowing head. Often, novice users of mowers, trying to charge the fishing line into a reel, forget to install the hold-down spring in the head, or even lose it when the lid is opened, and in the future, they are not even aware of its existence.

How to remove the reel and replace the fishing line

Owners of trimmers, mostly novices, are confused, bordering on panic when it becomes necessary to change the cutting tool or fishing line in the reel. Very often, when trying to unscrew the mowing head, users simply render it unusable, not suspecting that it is unscrewing in the opposite direction. To prevent this, if you need to replace the tool, it is recommended that you read the step-by-step instructions below.

  1. Before putting the fishing line into the reel, turn off the engine of the lawn mowers or de-energize the trimmer to avoid injuries that might occur if the cutting tool is accidentally started to rotate.
  2. Unscrew the nozzle attached to gear shaft. To do this, the shaft must be locked by aligning the holes on the washer and on the axis, and inserting a metal rod or screwdriver into them.
  3. Unscrew the nozzle. You should know that the thread on the shaft is left. Therefore, twist the trimmer coil to the right, that is, clockwise.
  4. Disassemble the mowing head. Most often, the head cover is attached on clips. To remove it, you will need to drown these clips into the body, squeezing the edges of the lid. If your trimmer has a semi-automatic mowing head with a button on the bottom, disassembling the nozzle should be done carefully, since you can lose the spring, which sometimes flies out when the cover is removed.
  5. Cut the required amount of fishing line. Usually its length is 5 meters. Use a cord of the diameter specified in the tool manual. It is not recommended to exceed the maximum diameter of the fishing line, as this will lead to increased engine load and higher gas mileage.
  6. Find the middle of the cord segment, folding it in half. You will get a loop.
  7. Cut through the coils special grooves (there may be holes). Insert a loop from the fishing line into this groove.
  8. Wind the line onto the reel by turning it counterclockwise. It is necessary to refuel the cord as evenly as possible, the turns should lie down without overlapping and with good tension. When the winding is finished, leave the free ends of the fishing line about 20 cm long and fix them in the grooves located on the sides of the reel.
  9. Assemble the mowing head. Before you finally assemble the nozzle, do not forget insert spring and washer (if available). Install the coil in the housing, and thread the ends of the cord through holes or eyes.
  10. Put on the cover and fix it with the latches.
  11. Screw the nozzle back onto the gearbox shaft, also locking it with a screwdriver. Spin the trimmer coil to the left (against the clockwise arrow).

Is it possible to make a coil on a trimmer with your own hands

  1. Take a piece of plywood or textolite and draw a circle on it with a diameter of about 14 cm.
  2. Cut the disc with a jigsaw or hacksaw for metal.
  3. Drill a hole in the center of the disk that matches the diameter of the gearbox shaft. Before installing the disk on the shaft, do not forget to put the washer on it.
  4. On the edges of the disk, you can screw small corners or make 1-2 holes on opposite sides. They will serve to refuel fishing lines in them.
  5. To fix the fishing line, several screws can be screwed into the plywood.

Such a homemade mowing nozzle is mounted on a shaft with a nut. Tighten or unscrew the nut without fixing the shaft will not work. To replace the cord, it will be enough to release the screws, insert a piece of fishing line of the required length and press it again.

Also, a mowing nozzle for attaching fishing line to it can be made from a metal sheet. How to do this, you can understand from the next video.