Petrol Trimmer Malfunction

Electric motors

Trimmers assembled on the basis of an electric motor are most often purchased when it is necessary to cut the grass in small areas. The power of the collector motors, which the hand-held mowers are equipped with, is about 250-500 W. As a rule, they are connected to a centralized network with voltage

220 V. There are also trimmers on the market with electric motors powered by batteries (Stihl FSA 130, etc.).

Petrol Trimmer Malfunction

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ICE malfunctions and ways to eliminate them

Most often, the internal combustion engine of the trimmer fails due to:

  • Breakage of parts of the cylinder-piston group (CPG);
  • Failure of the carburetor;
  • Ignition system malfunctions.

ICE breakdown manifests itself in different ways, for example, the appearance of extraneous noise during trimmer operation, or the inability to increase the speed to the value declared in the technical documentation.

Malfunctions of electric motors and how to eliminate them

The fact that the trimmer motor is out of order is indicated by:

  • Strong overheating;
  • Jerky work;
  • Complete inoperability.

In order to reanimate the motor of an electric manual scythe with his own hands, its owner must have certain knowledge in the field of electrical engineering, understand the design of the electric motor and have experience in troubleshooting malfunctions that arise during the operation of complex household products.

Next, you need to make sure if voltage is applied

220V to the contacts of the electric motor by pressing the power button. If there is voltage, this indicates that it is the motor that has failed. Otherwise, the power button is faulty, which is best replaced.


The magnetic core of the electric motor is made of special high-strength steel, and its breakdown can only be caused by extreme loads. Therefore, when repairing an electric motor, all attention is paid to the integrity of the windings and their insulation, as well as to reliable contact between the mating parts. The integrity of the windings is checked as follows:

  • Set the switch for the kind of work of the multimeter in the resistance measurement mode (the lowest limit);
  • Apply the test leads of the multimeter to the graphite brushes or directly to their contacts.

In the event that the device shows infinite resistance, it is recommended, without removing the probes from the brush contacts, to turn the motor shaft. If at the same time the multimeter shows a resistance in the range of 10 to 40 ohms, then the stator winding is intact, and if it is less than 5 ohms, then it has an interturn short circuit, as a rule, which occurs when the motor is overheated.

CPG repair

Failure of parts of the CPG, as a rule, occurs due to a violation of the timing of an oil change or a lack of it. This is especially true for two-stroke engines, where a lubricant is added to gasoline. After all, engine oil, aging, loses its lubricating properties, and the resulting sediment makes it completely unsuitable for operation. Another reason that can cause such a malfunction is insufficient fuel.

CPG malfunctions are considered the most difficult and expensive. after all, during repairs, it may be necessary to replace all parts of the piston group (cylinder, rings, piston, oil seals, etc.). It is better to entrust this kind of operation to specialists, because an incompetent intervention can "ditch" the motor completely. How the repair of the CPG is carried out can be seen on:

Internal combustion engines

The domestic market offers potential users gasoline trimmers equipped with both two- and four-stroke internal combustion engines with a capacity of 0.5 to 3.4 hp. Usually household lawn mowers, such as the Partner Colibri II S or the more powerful Hunter KS-250 model, are equipped with a two-stroke internal combustion engine with a cylinder volume of about 25-43 cm 3.

Four-stroke internal combustion engines, which are equipped with professional lawn mowers, for example, Husqvarna 537RX, run on gasoline, but two-stroke engines need to be filled with a specially prepared fuel mixture (40 parts of unleaded gasoline 1 part of machine oil). Owners of trimmers have to prepare the combustible composition independently, while observing the safety requirements:

  • The components are mixed in a separate container, and only when ready, the fuel mixture is poured into the tank;
  • Components must be combined outdoors;
  • Pour the fuel mixture into the tank away from the source of fire, while being careful not to let the mixture get on the engine body.
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In addition to the engine itself, the trimmer is also equipped with a system for starting it, consisting of a power button, a starting cable, a carburetor flap and a primer (fuel pump), which largely affects the performance of the engine.

A lawn mower or an electric trimmer, like any other complex tool, has a certain working resource, the value of which directly depends on the intensity of use. This fully applies to their motors.

gas trimmer device

The main unit of any gasoline tool is the internal combustion engine (ICE), which, through various methods, transmits the torque to the actuator. In a modern lawnmower, a duralumin rod (pipe) is used as a transmission element between the motor and the trimmer head, inside which the drive shaft is located.

Thanks to the high-revving engine, the line speed can reach 13 thousand revolutions per minute, depending on the braid manufacturer. In order to exclude mechanical and thermal damage to the gearbox, a special hole is provided in its housing for the introduction of grease in the form of ointments. To make the headset easier for the owner during long-term work, all lawn mower models are equipped with a durable shoulder strap.

Lawn mower cutting head

Regardless of the manufacturer, almost every model comes with a line and steel knives.

Trimmer cutting part

Cross-section of PVC trimmer line can vary from 1.5 to 3.0 mm.

Made of durable polymer, it is subject to intense wear and tear during mowing and, as a result, breakage. Therefore, from time to time it is necessary to check the presence of a fishing line in the head and, if necessary, replace it. It is recommended to purchase an additional spool for quick replacement with a spool with no line.

Trimmer malfunctions and how to fix them

Due to the presence of many components and parts, repairing a trimmer with your own hands means eliminating breakdowns that prevent its normal operation. The most basic malfunctions of petrol braids should be noted:

  • The trimmer motor is not picking up speed;
  • Breakdown of the cylinder-piston group (CPG);
  • Ignition malfunctions;
  • There is no connection between the internal combustion engine and the trimmer head;
  • Mechanical knocks during unit operation.
  • Repair of CPG lawn mowers

The main unit of any internal combustion engine is the cylinder-piston group (CPG), which can fail due to wear of parts of parts or poor quality of the fuel mixture.

Lubrication of the rubbing units in the lawn mower is carried out by adding a certain proportion of oil to the gasoline. This process can be disrupted due to old oil precipitating out. In this situation, when the trimmer is started, the motor overheats and in a matter of minutes the most expensive breakdown occurs. To eliminate the malfunction that has arisen, a complete replacement of the CPG will be required, namely: the piston, oil seals, cylinder and piston rings. If you are not an ICE repair technician and do not have experience working with technicians, then you will hardly be able to fix the engine without the help of a specialist. Details on the stages of piston trimmer repair can be found here.

Troubleshooting trimmer ignition

If the ignition of the lawn mowers fails, the spark on the candle disappears and, as a result, the fuel mixture does not ignite.

Spit spark plug design

It is quite important in this situation not to rush to replace the coil, since the cause of the breakdown may be the lack of contact in the switch on the control handle.

An important point when troubleshooting the trimmer ignition will be the section diagnostics, where the distance between the side and center electrodes should be 0.5-0.7 mm. In addition, it is necessary to pay attention to the steel O-ring on the spark plug, the loss of integrity or deformation of which can lead to etching of air from the combustion chamber and, as a result, reduce the power of the streamer.

Ignition flywheel with coil

If the replacement check of the electrical circuit, the spark plug and its contacts did not give positive results, then you should pay attention to the trimmer ignition module, namely, the flywheel clearance. Regardless of the design features and the manufacturer of the lawn mowers, the distance between the ignition coil and the flywheel should be no more and no less than 0.2 mm. To restore the optimal clearance value, you will need to loosen the coil mounting bolts and set the trimmer ignition with a special measuring probe.

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Petrol trimmer fuel system

A clear sign of a malfunction of the engine power system is the absence of traces of the fuel mixture on the spark plug electrodes, which may be associated with the following defects:

Trimmer Fuel System Components

  • Due to the clogged hole in the gas tank, a vacuum is created, which prevents the normal flow of gasoline into the carburetor;
  • Due to the poor quality of the fuel and the ingress of foreign particles, the fuel filter installed in the tank is clogged;
  • Failure to enter the mixture into the combustion chamber as a result of a clogged carburetor.

You can quickly determine the cause of the malfunction by dismantling the fuel hose leading to the carburetor. If the fuel mixture flows out in a thin stream, then you should pay attention to the carburetor. If there is no jet, it is necessary to clean the breather with a thin needle (a small hole in the gas tank cap) or replace the fuel filter.

Lawn mower management

Types of lawn mowers

ICE trimmers on the market today are equipped with a D-shaped, U-shaped or T-shaped handle, where the main controls of the unit are located. For example, in a U-grip braid, the throttle key and stop / start toggle switch are located on the right grip. In the D-shaped version of the handle, the throttle control button is located directly on the rod.

Petrol trimmers

Gasoline scythes are produced by brands such as Husqvarna, Huter, Champion, etc. Despite the variety of brands, the design of these devices is the same and does not fundamentally differ. So, on top of the lawn mowers there is an engine, next to it there is a container for fuel and a starter for starting the tool. There is also a switch that regulates the position of the air damper. This allows the engine to warm up quickly at low air temperatures and simplify its start. Further from the engine comes a rod with a rigid or flexible shaft for transferring rotation from the motor to the gearbox. The rod can be one piece or collapsible, consisting of several parts.

The device of the bar of the lawn mower is as follows. First, there is a handle on it, which has a different shape and is adjustable for the convenience of the worker. Secondly, on the stand (more specifically, on the holder) there are control keys connected to the drive with a special cable. Thirdly, in the lower part of the rod there is a gearbox that transfers the movement from the shaft to the spindle with the cutting unit. As a rule, the cutting part is a line (reel) with line or a metal knife. To protect the user, a protective cover is attached above the mowing head with a string or disc.

The principle of operation of the gas trimmer is as follows:

  • Using the starter, the worker starts the engine;
  • Rotation from the crankshaft of the motor through the shaft installed in the rod goes to the gearbox;
  • From the gearbox, the movement goes to the spindle with the cutting unit;
  • The cutting tool, rotating at high speed, cuts off the growth.

Popular devices of this type include the Partner "Kolibri" trimmer, "Patriot" equipment, etc.

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If the cutting edge of the trimmer is constantly spinning at idle speed of the engine, and an uncharacteristic metallic grinding is heard, these are signs of a faulty clutch. Usually the cause is a broken or stretched spring. If slip is added to this, then the pads are also faulty.

Drive shaft and rod

If a strong vibration appears during operation, this indicates the absence or lack of lubrication on the shaft inside the rod. In this case, even the anti-vibration system will not help. shock absorbers placed between the bar and the motor. To fix the problem, it is necessary to disassemble the braid and lubricate the shaft. And in order to avoid another manifestation of such a breakdown, you need to regularly service the device. If the vibration persists after lubricating the shaft, it must be replaced.

Electric group trimmers. mains

Electric trimmers are very easy to use and differ from lawn mowers in the type of drive used. they are equipped with an electric motor. The device of the Stihl, Soyuz or other brand electric braids looks as follows. The main part is a housing with an electric motor. It has power and lock buttons to prevent accidental starting, as well as a power cable with a plug. A split bar is attached to the body, equipped with an adjustable handle that allows you to choose the optimal grip for the mower, and a shoulder strap attachment. For easy storage and transportation, the rod can be disassembled into two parts. A trimmer spool is attached to the lower part of the stand, which consists of a spool with line, a protective cover and a knife for cutting the string to the required length. The rotation of the bobbin from the electric motor transfers the flexible shaft.

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Electric trimmers come in either an overhead or under engine mount design. In the first case, this is a technique with a power of up to 1.4 kW, which is able to cut tall and wet grass, as well as thin bushes. Such devices are equipped with a fishing line or a metal knife. Whereas devices of the second type have a lightweight mechanical part, since they do not need a gearbox and a shaft to transmit rotation from the engine. Their cutting unit is located on the motor spindle, which greatly increases the practicality and reliability of the design. However, such devices have a smaller number of revolutions and are able to cope only with young and not very dense growth.

To start working with the electric scythe, you need to connect the tool to an outlet and press the "Start" button on the body. This will start the engine, and the rotation from the rotor will go to the gearbox directly or through the shaft. Once the maximum speed is reached, the tool can be used to cut grass.

Typical malfunctions of trimmers of the gasoline group

The design of gasoline trimmers is more complicated than electric ones, so they have more breakdowns.

Start button

The first part to check if the tool does not turn on is the start button. The problem may be with it or a broken cord inside the device. For diagnostics, it is necessary to disassemble the handle and ring the parts with a multimeter.

What most often fails in a gasoline construction trimmer: how to determine a breakdown

The trimmer must be repaired as soon as the problem occurs. Otherwise, more serious problems are fraught.

And it can completely fail. You can bring it back to normal with your own hands. Depending on the nature of the problem and the level of technical knowledge of the person.

All models of this technique are characterized by the presence of such details:

  • Engine. drive system;
  • Transfer type devices;
  • Knife with a fishing line;
  • Belt and handle.

About the main malfunctions of lawn mowers

Most often, problems relate to:

  • Motor;
  • Carburetor element;
  • Barbell;
  • The rope breaks on the starter, the spring breaks or disengages);
  • The ignition system or the fuel system is lousy;
  • Reducer;
  • Filter and silencer system.

How to identify a breakdown

If there are problems, the following is observed:

  • The lawn mower makes atypical sounds;
  • Does not respond to switching on or rotates weakly;
  • The engine in the working part does not spin well;
  • Fuel leaks;
  • The nodes get very hot;
  • The start button falls;
  • The limiter falls off;
  • The line breaks or the knife becomes dull.

How to fix

To disassemble the lawn mowers and lubricate its parts, when it is necessary to replace faulty elements, they arm themselves with tools:

  • Screwdrivers;
  • Wrenches;
  • Puller;
  • Special wrench for candles;
  • And with a hammer.

Repair is not possible without disassembling individual units. Some models come with a non-separable starter.

When you need to disassemble and replace the barbell, it is important to know its elements:

  • Drive shaft;
  • A tube;
  • Sleeve;
  • Shock absorber;

It is important to lubricate the shaft after disassembling the rod. Sometimes you need to replace a worn rod.

Clutch repair works like this:

  • The muffler cover is removed;
  • The metal stand is removed;
  • The side screws are unscrewed to remove the shock absorber cover;
  • The tube is taken out;
  • The clutch spins;
  • A new spring is installed.

If the engine malfunctions, it may be necessary to replace the following parts:

  • Pistons;
  • Oil seals;
  • Or rings.

For troubleshooting, the drive motor is dismantled and worn mechanisms are replaced.

If necessary, you can replace the piston rings as follows:

  • Removing the cover on the plastic case;
  • Disconnecting the crankshaft rod;
  • Removing the cylinder head;
  • Recess of the piston and rings;
  • Replacement;
  • Assembly.

In case of serious problems, it is advisable to contact a specialist.