Electric Trimmer Malfunction

Fuel supply and ignition system

In most cases, malfunctions occur precisely in this area, and each owner can fix such problems with his own hands.

  • If attempts to start the lawn mower do not lead to anything, or it stops working after a couple of moments, then problems in the ignition system can be considered as a possible reason. To confirm this hypothesis, you should remove the candle and examine it. If there are signs of a fuel mixture on the body, it can be concluded that the problems are related to the adjustment of the carburetor. The presence of black carbon on the candle indicates the need to replace it. Most often, there are no problems with the search for similar accessories for trimmers.
  • The body of the plug can be covered with carbon deposits if low-octane gasoline is used as fuel or the device operates in a cold start mode with violations.
  • A dry candle may indicate that the problem is with a clogged fuel hose. This will be confirmed by the flow of gasoline from the disconnected hose. If nothing like this happens, then you need to examine the filter: if there are signs of clogging, a new product is installed instead. Also, the reason may lie in Sapunov, which can be restored to working condition by cleaning it with a needle.
  • When diagnosing a gasoline trimmer, it is important to pay attention to the muffler: very often its body is covered with carbon deposits. In this case, it must be removed, cleaned with kerosene and burned out with a burner.

Engine malfunctions

If the failure of the trimmer is associated with an inoperative engine, then in this case it will not be so easy for the owner to understand what was the cause of the problem, and how it can be eliminated. It’s good if the device still has a warranty, in this case, you can take the trimmer to a repair shop, whose specialists will quickly and efficiently cope with this task.

Electric trimmer repair. Problems Electrical Apparatus

Equipment that operates on the network differs from Similar devices that provide an integrated power drive in that it has a simpler design. The main components of a trimmer are:

  • The mechanical part that transmits torque to the trimmer head;
  • Electric motor;
  • Power cable.

In this case, all the problems that may occur with this equipment can be represented in the form of the following groups.

The main function when using the device is assigned to the trimmer head, in which the cutting surface is made of fishing line. In most cases, the device fails due to problems with its supply.

  • If the line is used up, it is necessary, following the instructions of the instructions, to wind a new.
  • One of the reasons for stopping work may be line tangling. In such a situation, unwind it and insert a new bobbin if it shows signs of damage.
  • Also, the trimmer may fail due to stuck nylon thread, which may be due to overheating of the device during its long-term use. This problem is solved by rewinding the line.
  • Problems may be directly related to the coil: for example, the bottom may fall off into it. Repair in this case will be reduced to replacing it or creating a new bottom with your own hands. Having chosen the last option, it is necessary to prepare a piece of PCB or a bolt with a nut.
  • In some cases, the coils may show no signs of damage, the motor may also be fine, but the head does not rotate. In a similar situation, you should look at the drive shaft. If the fear of its breakage is confirmed, then the device must be returned to the service center.

If the failure of the gasoline trimmer is associated with malfunctions in the mechanical part, then the repair technology will for the most part repeat the work carried out in relation to electric models.

To carry out repairs to electric trimmers, prepare the Appropriate Tools:

  • Indicator screwdriver;
  • Multimeter;
  • Blowtorch.

Regardless of the nature of the malfunction, this in any case leads to the termination of engine operation.

  • If there are signs of damage to the power cable, then you will need to consider installing a new.
  • If the problem lies in the outlet, then in this case you need to make sure with an indicator screwdriver that this is really the case. If the fears are confirmed, then you should choose another outlet for connection.
  • Engine failure may be due to fork damage. In this case, it must be disassembled and replaced with a workable product.
  • Sometimes problems can be associated with the control knob. First, you need to make sure of this, for which they use an indicator screwdriver: if there is a break in one of the wires, then the contact will not close. In this case, the damaged wiring is replaced.
  • Motor stator winding can also cause loss of motor performance. First, a check is performed with a multimeter. For this, the measuring device must be switched to a mode of operation with a minimum resistance, and then its probes are connected to the graphite brushes. If there are no resistance readings, then based on this, it can be concluded that the winding is burning. The repair will be limited to installing a new engine. Usually, there are no problems finding the necessary spare parts for an electric trimmer.
  • Also, the engine may fail as a result of breaking one of the contact connections. If there are no signs of damage to the winding, check all connections using a multimeter. When the damaged contact is found, you need to write it yourself.

Electric Trimmer Malfunction

Equipment of this type is more complex, since

, but also a number of other elements: gas distribution system, fuel tank and control.

Electric trimmer diagram

Line trimmer wiring diagram, simple, consisting of:

  • Potentiometer, motor control speed;
  • Capacitor

And directly the electric motor itself.

The cause of the malfunction at the beginning during visual inspection was incomprehensible, the trimmer had to be completely disassembled to determine the true cause of the breakdown.

  • The trimmer does NOT cut the grass. Most often, the culprit of the problem is a broken cutting tool. If you use a trimmer with metal knives (cutters), chances are they are dull and need sharpening. If the grass is being cut with a trimmer line. Replace the worn out line with a new one.
  • The device vibrates strongly during operation. Most likely, the reel seat is clogged with cut grass particles, or the reel itself is out of order. In the first case, remove the coil and clean the landing socket from the blockage. In the second. Replace the defective part with a serviceable one. If you do not have experience in disassembling the trimmer, it is better to do it next to professionals.
  • The electric trimmer motor does not start. First of all, check the presence of voltage in the power supply network, the serviceability of the plug and cord. Pay particular attention to traces of melting, cable kinks and broken cable insulation. If they are serviceable, the graphite engine brushes may have worn out. Defective elements should be repaired or replaced with new ones.
  • The paddle knife stopped turning. If the electrical part of the day is not the culprit, then it will be better to seek help from the service center.
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1. The trimmer motor will NOT start. The causes of the problem may be malfunctions in the trimmer ignition system or the use of low-quality fuel (mixture).

Typical fuel problems:

  • Use of low-quality (counterfeit) gasoline contaminated with various impurities;
  • The presence of water in gasoline;
  • Excessive fuel level in the tank (cylinder)
  • Using a fuel mixture with the wrong proportion of gasoline and oil.

Typical problems in the ignition system:

  • Damaged or dirty spark plug;
  • Incorrectly set gap between the spark plug electrodes. The easiest way is to replace the problem candle with a new one or seek help from specialists.

2. When the engine is running, characteristic knocks are heard. The knocking can be caused by a damaged cylinder, crankshaft or bearing. All damaged parts should be replaced with good ones. If the trimmer engine makes a metallic knock during operation, it is possible that you have selected the wrong type of fuel mixture (gasoline with oil or gasoline with an additive).

3. Faulty trimmer ignition system. Such malfunctions are caused by water trapped in the fuel mixture or problems with the spark plug.

4. The trimmer motor suddenly stalls. Usually such reasons are caused by a lack of fuel mixture in the tank, a malfunctioning spark plug, or damage to the high-voltage wire in the ignition system.


The owner of a gasoline or trimmer always needs to be prepared for the fact that at some point this equipment will need to be repaired. At the same time, contacting a service center is not always the right decision. Often, the causes of a malfunction can be quite simple, which can be eliminated at home. The main thing is to know where to look for her.

Cutting blade

One possible breakage of the cutting blade. The cassette cover is displaced or stuck. This is due to a misalignment of the axle or the installation of an unsuitable mowing head. As a result, rotation becomes difficult, the load on the motor increases, and it overheats.

If the blade does not rotate, checking the assembly depends on the boom design. For a curved shape, you need to inspect the bushing and the bar itself, and for a straight one. Shaft, gear and clutch. All connections between parts must be intact. This check is only performed if the trimmer motor is in good working order. Sometimes confusion occurs, and users think that the problem is with the cutting unit, but in fact the motor is faulty.

Typical trimmer faults

There are far fewer knots on electric trimmers that can break. These are details such as the power button and the electric motor. Also, mechanical malfunctions of electric scythes are not uncommon.

Electric group trimmers. Rechargeable

There is another type of electric trimmer. Rechargeable. These tools are low power and are NOT designed for continuous operation (15-25 minutes on average, when fully charged in 3-4 hours).

The advantage of this type of technique. Mobility and low noise level, therefore it is used in areas where noise is not allowed. These are hospitals, hotels, sanatoriums. In addition, the use of these trimmers is relevant in cases where the electric cable greatly interferes with work and movement. However, before each turning them on, you need to check the battery charge.

Exhaust system

If the lawn mower stalls when the user clicks on the gas and revs the engine, it could be a forgotten exhaust system. This is due to the large amount of burning generated during the combustion of the oil that is part of the fuel mixture. To fix the problem, you need to clean the muffler and related parts.


This mower unit breaks down due to poor quality fuel, accumulated dirt in the chamber, and a deformed air filter. Parts such as diaphragms, inlet needle, seat, strainer, adjusting lever, flaps, etc. can clog or break. Device diagnostics and subsequent cleaning or repairs are required. In some cases, carburetor adjustment is required.


A trimmer gearbox is used to transfer rotation from the shaft to the cutting head. It includes a housing, bearings and gears. On its part, there may be the following malfunctions.

  • The transfer unit is heating. The reason lies in the absence or unsatisfactory quality of the lubricant. It needs to be added or completely replaced. Also, this phenomenon can manifest itself when new gears are installed. In this case, you need to let the tool work under light loads, regularly interrupting work in order to avoid overheating of the equipment.
  • Knocking, backlash, shaft seizing speak in bearing deformation. Replacement required.
  • The transmission wobbles or flies off the bar. It means. The case is damaged. It is necessary to replace the rod or tighten it with a metal clamp if the damage is minimal.
  • The reducer does NOT support the stem. This is typical for a worn out joint. You can change the rod or wind up the electrical tape.
  • The knife does NOT rotate or stops when loaded. Means. Gears are worn out (completely or partially). Parts need to be replaced.
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Electric trimmer malfunction

An electric scythe or a trimmer, like any electric tool, has a limited service life. With an increase in the intensity of operation for various reasons, the life of the device decreases.

You should be prepared that at any time during operation, the electric braid can break, but such situations can be avoided if you regularly disassemble, inspect and revise all the fundamental elements of the braid.

Malfunctions of electric scythes can be very diverse, it can be either a breakdown in the electrical part of the engine and wiring, as well as in the mechanical part.

In most cases, it is not difficult to repair a trimmer or braid and you can do it yourself if there is a minimum tool and basic concepts in technology. Well, for the readers of the site elektt.Blogspot.com, I will reveal the main faults and secrets for a quick and reliable repair of your electric braid, consider an example of repairing an electric braid from Bosch and Gardener.

The design of most electric scythes is NOT a complex device, the main components, whether it is a trimmer or a scythe, there is an electric motor, a power wire, a button with a capacitor, a spool with a line that is fixed on the motor shaft or more complex mechanical options for braids where torque from the motor is transmitted to the spool through flexible shaft, but among electrical options for braids, this option is rare.

Electrical faults

To identify faults in the electrical part, as a rule, just an inspection is not enough; you need a multimeter or at least a tester with a dial tone. Such malfunctions are characterized, as a rule, by a complete inoperability of the engine, severe overheating or jerk work.

The check begins with the power cable, if it is damaged, it is either repaired or replaced. Express check involves checking the voltage of 220 volts at the engine contacts.

The voltage should appear when the button is pressed, if the voltage is present, then we can safely say that the trimmer motor is faulty, it must be disconnected and carefully inspected. Slight contamination of the collector plates and brushes is normal, but it is still better to clean with a soft cloth moistened with alcohol, if the brushes are clearly worn out, it is better to replace them.

Using a multimeter in the resistance test mode (the smallest limit. Ohms), touch the contacts of the brushes or the most graphite brushes with the probes, the tester should show a resistance of NOT more than 100 Ohm.

If the resistance is infinite (one per multimeter), then try not to absorb the test leads cranked the motor shaft. In a properly functioning electric motor, the resistance wakes up about 10.40 Ohm, if the brushes DO NOT ring out, then there is no contact or the integrity of the stator windings is broken, possibly an open or burnout. When the resistance is less than 5 ohms, there is an interspeed short circuit, most likely caused by a strong overheating of the engine.

The following procedure can be used to identify the specific cause of a motor malfunction when the motor brushes are NOT ringing. The graphite brushes must be pulled out by first pushing out the brass inserts or by removing the hold-down springs.

The collector motors in these devices are arranged in such a way that the stator and rotor windings are connected in series, and in expensive models of electric motors a thermal relay is also connected to this serial circuit (110 degrees), such a relay in normal conditions keeps the power contact closed. A separate diagnostic method can be checking the resistance on the plates of the collector drum.

In order to identify the culprit of the malfunction, it is necessary to remove the insulation in the form of cambrices from the fluoroplastic where the windings and the thermal relay are connected and ring each winding separately with a multimeter, as well as the thermal relay.

Mechanical faults

The most loaded mechanical elements in the electric braid are bearings and a trimer reel (spool). In most cases, the device stops mowing due to the failure of its line spool

The line ran out. According to the instructions provided, wind the fishing line on a spool.

The line is tangled. If the reel is not damaged, then you need to cut or unwind the line and, if necessary, rewind the entire spool.

The line is stuck together. Due to the rather intense work and high overheating, the plastic threads of the fishing line can fuse with each other. Need to rewind the spool with new line and inspect the damage to the bobbin itself.

The motor is running but the line spool is NOT spinning. Most likely there was damage to the structure of the reel with line. The attachment points to the bottom of the spool may break off, you need to completely disassemble the bobbin and, if necessary, modify the mount or completely replace it. In most electric trimmers, the bobbin is simply pressed by its plastic housing onto the motor shaft and, with severe overheating, when the plastic melts, it can turn and fly off altogether.

Both devices showed no signs of life, the engines did not work when turned on.

The case in both devices consists of two halves, the self-tapping screws are on one side, which is convenient for disassembly. After all the screws have been unscrewed, the upper case is separated from the lower one by gently pressing it into the slot with a flat screwdriver to open the interlocked plastic locks.

After disassembly, we proceed to inspect the insides and troubleshoot.

During the inspection, it was found on the Bosch trimmer engine, on one of the brushes, which is fixed by the pressure spring, copper conductive wires flew off, which naturally was a prerequisite for the absence of voltage on the brushes and the engine did NOT rotate.

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The wire was restored to its place, and along the way the collector pads were cleaned, with a soft rag soaked in alcohol, to a copper luster. The brushes were in good condition and did not need replacement.

It was also found that the switch does NOT create a reliable electrical contact, it was necessary to clamp the button with a clamping force, it was decided to disassemble the button, its contacts were cleaned of carbon deposits and smeared with a current protective spray KONTAKT S-61.

With the GARDENER electric scythe, it was not so simple, it lay long enough, did not have time in a broken state, and in the literal sense of the word “broken”, its rod at the place where the engine body was attached was broken in half, apparently so difficult were the conditions of its operation.

With the help of perforated plates from the metal profile mountings, a new mount of the engine body to the Electric Scythe Rod was NOT cleverly made. The integrity of the structure is restored, albeit NOT in an aesthetic but reliable way, because the main thing in the electric braid is its functionality.

The engine shaft was turning noticeably hard, and an internal examination revealed burnt collector plates and worn brushes. The plates were sanded to a shine and the brushes were replaced with new ones.

In view of the long operation without lubrication and the subsequent storage of the device in an aggressive environment, the bearings are a little stuck and the motor shaft did NOT naturally rotate with difficulty. The engine bearings were washed with WD-40 spray followed by lubrication. As a result, the engine began to rotate noticeably better, but still the bearings were already “broken” and when the engine was running on the mains, the sound of its operation was not so smooth and monotonous.

Further inspection of the electrical part led to the button, it was completely broken from its mountings, although it was pressed, but the tester showed its malfunction. The buttons are not collapsible, so it was replaced with a new one. The fasteners had to be restored with hot melt glue.

In addition to the broken bar, there was a crack on the plastic protection, apparently someone did not drop it weakly. The scythe could work with it, but it was decided, as far as possible, to restore the protection structure.

It is natural to simply glue such a loaded and impact-prone object with glue. It would not be a reliable solution. Therefore, using the same perforated plates from the metal profile, two brackets were made that created “monolithic” connection of two parts of a cracked case. The plates were connected to the body with aluminum rivets.

When the lawn mower was assembled, it was found that the bar at the points of attachment of the handle was poorly fixed and rotated, therefore, the places where the plastic protrusions of the handle body were pressed against the metal of the bar were additionally sealed with a strip of cloth tape. Now the construction has no extra backlash.

The main most common malfunctions of the electric scythe and trimmers

DOES NOT cut the grass

The spool (spool) runs out of line. In most spools, the net feed is Semi-automatic, with a light hit of the spring-loaded button on the ground, the line is fed to the exit. If the line does NOT feed, then you need to remove and disassemble the spool. I spool and, if necessary, wind new line.

The fishing line may be too long due to the fact that the blade, which is intended for cutting excess line along the length of the blunt line, or it does not exist at all. The length of the line should be slightly less than the diameter of the protection.

Vibration during operation

A large hum and vibration during engine operation may indicate that the bearings need lubrication or they have completely used up their resource. There may also be a cracked reel body with line (spool), and its attachment point must be inspected for cracks and damage.

Decrease speed

Most electric motors in hair and trimmers are commutator and do not have a speed regulator, with a decrease in mains voltage. Reduced speed and power. The line spool may not be wound correctly. Perhaps the turns are hampered by the presence of a stuck twig or a rope is wound around the shaft, you should inspect the structure. In a working order, the oblique shaft should turn easily and without the slightest effort even after it has been dispersed with a finger.

Electric scythe does not work

Does the engine NOT turn? We look at the presence of power on the plug, if everything is in order then the device needs to be disassembled. If no obvious damage is noticeable, then a sequential continuity of the electrical circuits of the device begins.

With the help of a multimeter (tester), they first ring out the power cord, the fuse, if there is one, and the button. If the buttons do not ring in the power-on state, then it should be replaced or if it is collapsible, then open and clean the burnt contacts.

The cord may be broken, in which case the engine may intermittently start. An engine malfunction may be the fact that when the button is turned on, there is a voltage of 220 volts on the engine contacts, but it does not rotate.

Some electric motors are equipped with a thermal fuse, which is built into the motor housing and tripped due to its overheating or simply failed. A working thermal fuse must restore its operation when the engine cools down.