How to Unscrew a Stihl Mower Trimmer
Repairing the gas trimmer starter may be necessary at the most inopportune moment. At the same time, there are two ways to solve the problem: replace a broken part or change the entire assembly. The latter option will cost more. To repair the device with your own hands, in most cases you will need from the tools only a screwdriver with the appropriate tip. Repair work does not take much time and does not require special knowledge. It is enough to know the device, the principle of operation, the nuances of the assembly-disassembly of the starter on the trimmer to achieve the desired positive result.
The device and principle of operation of the starter on the trimmer
Gas engine. this is, in principle, the main part of lawn mowers. Its power lies in the range of 0.5-2.5 hp. The movement from it is transmitted to the shaft located inside the hollow rod, and then through the gearbox consisting of gears, already a fishing line or knife (working body).
Also, the lawn mowers have the following elements:
- protective cover;
- a belt designed for ease of use of the device;
- a starter used to start a gasoline internal combustion engine.
All details of the lawn mowers are presented in the photo below.
The starter on the trimmer is an integral part that starts the engine to work. It is depicted separately in the two photos below.
Starter mechanisms of various lawn mowing models work on the same principle: during the start of the internal combustion engine, the protrusions marked with the number 1 in the photo above enter the hook with the dogs 3. When the engine starts to work, they return to their previous position due to the action of centrifugal force. A similar role is also played by wires 2.
The process of returning to the initial position of the elements of the mechanism occurs due to the presence of a spring wound around an axis. It unfolds when the rope is pulled. After releasing the cord, it is retracted and wound due to the folding of the spring. During the start of the ICE lawn mowers, the trigger mechanism rotates its shaft until it starts to work (starts).
Today gasoline lawn mowers equip starter mechanisms of two types:
The first option is much more common.
The starter on the trimmer can function without breakdowns for a long time. Unambiguously indicate the period of uptime is impossible. Everything is determined by the initial quality of the device and compliance with the rules for handling it.
The main malfunctions of the trimmer starter
It is not difficult to determine the cause of the breakdown of the starting device. There are several main options:
- breakage of a cord (rope);
- when the spring breaks or disengages.
The indicated details are shown in the photo below.
It may happen that the starter mechanism is accidentally broken. The consequences will be deplorable if a tattered rope is wound around the flywheel of an internal combustion engine: then the spring will burst, the pulley will rip off. But such cases when a complete replacement of the starter assembly is required are extremely rare. In most cases, to fix the mechanism, it is enough to put a new spring or replace the cord.
Video: How to Unscrew a Stihl Mower Trimmer
Removing and disassembling the starter, replacing broken parts
To repair the trimmer starter, you will need to disassemble it first, and then assemble it. This process is not particularly difficult. You will need to work shape screwdriver.
Everything should be done carefully, observing safety precautions, mainly so that the spring does not injure the master during an accidental departure.
Analysis of the starter assembly
Disassemble the start-up mechanism in order to install new parts instead of broken parts in the following sequence:
- unscrew the screw fixing the pulley with a starter cover with a screwdriver;
- take out the spring and antennae;
- carefully remove the pulley (you need to turn your head away or work, having previously worn glasses and gloves);
- determine why the trigger mechanism has broken;
- if the spring has collapsed almost completely, then it is replaced;
- when the spring exits the hook, it is installed in its original place by bending the antennae before it (the photographs show the installation process);
- after the spring plate is installed inside the groove, carefully twist it.
To change the spring, work should be carefully and accurately: it can accidentally burst under the influence of the force caused by putting it in place. Even if you carefully remove the roller, the spring band flies off the reel very quickly and can injure your hand with its sharp edges.
Immediately put in place the spring plate does not always work. It often slips, so attempts must be repeated until the desired result is achieved.
The assembly of the starter assembly is carried out in a number of stages:
- the coil is turned over, installing it so that the spring bend exactly fits into the groove of the case, as in the photo below;
- stack two washers, between which a spring is placed;
- put in place a cup with a mustache;
- tighten the screw (photos below).
When doing the above manipulations, it is necessary put two washers. If this is not done, then the spring will eventually damage the plastic cup, and when it is pulled, wedging will begin. Because of this, a feeling appears, as if the spring has flown. To eliminate this drawback, you need to install this part of greater length or an additional washer.
When such parts are missing, you can just a little bit unscrew the screw, and the starter assembly will start to work without wedging. But this option is temporary. it is better to repair it qualitatively as quickly as possible.
After installing the spring, tighten it. To do this, perform the following steps:
- remove the handle from the starter cord;
- then the rope is inserted into the reel groove;
- spring is tightened by rotating the coil in the opposite direction to the clockwise direction (winding);
- make the required number of revolutions indicated in the operating instructions for the trimmer model used and corresponding to the length of the cord used;
- at the very end, the rope is threaded into the hole provided for this, located in the starter cover;
- put the handle in place, fixing it with a knot.
If after repair the spring continues to fly, you can get rid of this in the following ways:
- cram a suitable piece of plate into the groove at the location of the spring hook;
- Drill holes on both sides of the groove in the coil, into which to insert the spring hook and fix it with a wire.
Replacing a torn cord
A torn rope is replaced in the following sequence:
- the old cord is removed;
- choose a rope of suitable size (thickness and length);
- passing it through a special hole located in the coil, tie a knot;
- cock the spring, producing the required number of revolutions;
- fasten the handle.
It is better to tighten the spring plate together with the partner so that the edge of the cord does not wound inside the starter mechanism.
It is not difficult to assemble the starter on the trimmer and wind the spring, only this should be done carefully and with caution. For different models of lawn mowing, the breakdowns of the starting mechanisms are the same, therefore they are repaired in a similar way. There are some nuances associated with their design features.