Repairing the petrol trimmer starter may be necessary at the most inopportune moment. In this case, there are two ways to solve the problem: replace the 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, in principle, is 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 into operation. 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 mechanism elements 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 operating ICE: 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.
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.
Starter assembly analysis
Disassemble the start-up mechanism in order to install new parts instead of broken ones 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 photos 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.
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 used trimmer model 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);
- threading 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 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 failures of the starting mechanisms are the same, therefore they are repaired in a similar way. There are some nuances associated with their design features.
Video: How to Disassemble a Plant on a Video Trimmer
lawn mowers are a popular seasonal tool designed to remove unnecessary vegetation in the house area. Like any other equipment, these devices periodically break down. Repairing the trimmer ignition coil is one of the most common problems encountered with gasoline braids. The ignition system itself is designed similarly on two- and four-stroke ICEs, so the elimination of breakage is performed almost the same for tools from different manufacturers, whether it be Lux, Huter, Husqvarna or another brand. Ways to restore the efficiency of the ignition coil or replace it with a new one are in the material below.
Magneto. design and concept of work
The purpose of the ignition coil is the conversion of rotational energy into a high voltage discharge and the formation of a spark igniting the fuel mixture. In an internal combustion engine, this part is called magneto, since in it an alternating current is generated from the rotation of a constant magnetic rotor or armature.
Magneto constructively consists of two windings: high and low voltage. A capacitor with breaker contacts is connected in parallel to the latter. Whereas the findings of the high voltage winding are connected to the candle and the housing. Both of them are wound on a core, between the poles of which a rotating magnet is installed, magnetized longitudinally.
Before you start diagnosing magneto, you need to make sure that the problem is actually in this node. To do this, you need to check the entire circuit and make sure that there are no other reasons for the failure of the trimmer.
- First you should carefully inspect reel for cracks and other external defects on the case. Next, you will need to examine all the elements and nodes that conduct current, and make sure that they are clean.
- The next step is inspection high voltage wires. They must be intact and securely attached to the contacts, free of rust and with intact insulation.
- The next step will be checking candle cap. As a result of careless actions, the user often tears it from the high-voltage wire, and then improvises and creates a makeshift mount. It must be understood that any poor-quality connection in this place significantly reduces the power of the electric arc of the candle.
- Then you should make sure that she candle good condition. If you fill the lawn with low quality gasoline, the life of this part is significantly reduced. In addition, it can be flooded or have a large soot that impedes work. Sometimes the candle even sticks and does not unscrew.
- Next, you need to inspect circuit breaker. On Chinese-made trimmers and chainsaws, it very often breaks.
Having completed all these steps and excluding the listed nodes from the list of possible causes of failure, you should proceed to checking the coil. This can be done in several ways.
The first way that the ignition coil is checked involves the use of special equipment (stand). At home, it is not available. you can find it only in service centers.
Diagnostics of magneto using a multimeter is a solution that can be implemented on their own with such a measuring device. In this case, you must do the following.
- Switch on the resistance mode on the measuring device and set the value to 200 Ohm to test the primary winding.
- Connect the electrodes of the multimeter to the “mass” of the magneto and the output contact. If the winding is intact, the resistance will vary from 0.4 to 2 ohms.
- Turn on the 20-com tester to perform secondary winding diagnostics. In this case, the first probe is connected to the “mass”, and the second is installed in the candle cap. Normal values are at least 4-6 com. If the circuit is damaged, then the tester will show infinity, and in the case of a short circuit. zero.
The exact data on what the tester should be during the verification of the primary and secondary windings can be found in the instructions for using the trimmer.
If there is no multimeter, you can check the coil in one more way.
For diagnosis, you need to perform the following steps:
- open the cover with which the cylinder is closed;
- remove the cap of the high-voltage wire from the candle without unscrewing the part itself to maintain compression;
- tightly place the nail in the cap without a hat, it will imitate the central electrode of the candle;
- bind the cap with a nail to the cylinder with a dielectric material so that the gap between the candle electrode simulator and the mass fluctuates from 5.5 to 7 mm (the exact distance for a particular model is recommended to see in the user manual), but the part does not come into contact with the mass;
- Starter several times to start the engine, holding the ignition button in the on position;
- if a spark appears, you need to consider what color it is.
A white or bluish powerful spark is normal, and a faint glimmer of an orange or yellow hue indicates a broken coil.
Often, cold magneto creates a powerful spark, but when heated due to a defect in the internal components, it does not conduct current. After cooling, the lawn mowing coils start up again and mow the grass with a fishing line or knife before heating the magneto. This is abnormal behavior, so the coil needs to be changed.
Common Problems. Causes
Faults that most often occur with magneto are typical of trimmers from different manufacturers. As a rule, this is a weak spark or its absence, as well as interruptions in this process.
If magneto flickers intermittently, check first contacts. They could be burnt or oily. Detected carbon deposits are cleaned with a file, and the oil is rubbed with suede, previously soaked in gasoline. The second possible cause of the problem is misregistration. clearance between contacts. To eliminate it, you need to set the correct distance.
If the spark appears intermittently, it may also mean that breaker lever pad worn out. To eliminate the malfunction, it is necessary to change the lever to a new one. In addition, you should adjust the gap, as with another possible cause of failure. adjust the outline.
Breaking through capacitor may also be responsible for interruptions in spark formation. In such a situation, the replacement of the damaged part is required, since it is impossible to repair and recharge it.
Lack of sparking
If magneto does not give off a spark at all, the main reason is breakage of one of the transformer circuits (primary or secondary). To repair the lawn mow, the defective part must be replaced. If happened primary circuit short to ground, it can also cause a lack of spark. You must fix it to fix the problem.
Lack of sparking
A faint spark on magneto is caused by a damaged capacitor. To eliminate the breakdown, it is necessary to replace the failed part.
In order to repair a magneto with your own hands without the involvement of specialists, you need to know how to disassemble it, and how to change the breaker contacts to new ones.
Dismantling magneto is very simple. First you need to remove this device from the engine and clean it, eliminating oil particles and dirt. Further, since the ignition timing unit is securely fixed, you need to unscrew the nut, and then remove the part and pull the key out of the groove. The cover is fixed on four screws. To remove it, it is necessary to unscrew and remove the fasteners. Then you need to remove the magneto rotor from the housing, unscrew the studs holding the transformer, and remove it. And to collect magneto, you need to perform the above steps in reverse order.
Replacing breaker contacts
After disassembling the magneto, it is necessary to remove the old contacts of the breaker and install the new ones correctly. To implement this, you must:
- move the latch, remove the cover from the breaker;
- unscrew the screw holding the connecting conductor;
- remove the screw securing the breaker plate to the magneto cover and remove it;
- to get the screw fixing a spring of a breaker;
- remove the lock washer from the axis, and then the lever with the pillow assembly that it holds;
- unscrew the screw securing the contact pole, remove the part from the axis.
Assemble a node with new contacts in the reverse order.
To remove magneto, you need to remove the plastic casing from the trimmer. On different models of lawn mowing, this process is different. Usually it is necessary to unscrew the bolts, but some gas trimmers may need to release the latches. After that, access to the coil is opened. To remove the part, unscrew the retaining fasteners and disconnect the wires.
When installing a new part, you need to competently set distance between flywheel and magneto. To do this, turn the flywheel with the magnets up, install the coil and secure it, but do not fully tighten the screws so that there is a small distance between the parts. Next, between the coil and the flywheel, you need to put a pocket calendar, a business card or a folded four-fold A4 paper sheet, you can also use a plastic strip cut from a bottle. Such tricks will provide a suitable gap between the flywheel and magneto. A more competent solution would be to use a special template, but to acquire it for the sake of one time is impractical. Next, you need to tighten the fasteners, remove the object located between the parts, and, holding the magneto with your hands so that it does not spin, tighten the fixing screws tightly. After this, turn the flywheel and make sure that it does not catch the coil anywhere. Now you need to connect the wires and insert the candle into the cap, and then check the operation of the device.
Often, breakdowns of ignition coils are associated with a short or open winding and mechanical damage to the magneto body. This is due to strong shocks, fluid and oxidation, as well as overheating. If such incidents are avoided, there is no need to worry about the integrity of the ignition coil.
One of the magneto nodes that regularly suffer during use is high-voltage wires, through which current is supplied to the spark plugs from the ignition module. They have a high service life, but users themselves cause damage to them by inaccurate handling when replacing candles, inadvertently pulling on the wire itself, and not on the tip. Another problem that can occur with them is moisture and oxidation or damage to the insulation. By carefully pulling out the candle and avoiding the ingress of liquid into the device, these problems can be avoided.
So, the repair of the ignition coil is not very difficult and can be carried out by the user independently, but subject to the above procedure for disassembling and replacing the magneto or the breaker contacts.
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