Lawn Mowers Malfunctions And How To Fix Them

How lawn mowers are repaired?

Lawn Mowers Malfunctions And How To Fix Them

  • Device
  • Symptoms of common problems
  • Remedies
  • General recommendations of specialists

A personal plot or adjacent territory does NOT do without the help of a lawn mower. In the warm season, this tool gets the maximum work. Before you start using your lawn mower, you should prepare it correctly. It is also important to monitor the serviceability of the tool and fix breakdowns in time. You can cope with the most common malfunctions on your own, I learned a little more about lawn mowers.


It is best to start repairing lawn mowers with a step-by-step check of the main components. The first thing to check. This is fuel in the tank, as well as the presence of lubricants on the main units of the tool. It is also important to know what quality and what is the proportion of fuel and oil used. If something is wrong, the piston system may fail, and its replacement is expensive.

Next, it is worth assessing the serviceability and performance of the spark plugs. The result is judged by the presence of a spark when there is contact with the tool body. If the malfunction is in the candle, then you need to remove the voltage wire from it.

In case of contamination, it is recommended to replace it with a new one and dry the candle channel. They also do this if there are cracks or chips on the candle body. The gap between the electrodes is set at 0.6 mm. Clamping of a new candle is also done with a special key. At the end, a voltage wire must be connected to it.

Inspection of filters, both fuel and air, will be useful. If the blockages are strong, then replacing them is the best solution. You can try washing the air filter with water and adding detergent, and then dry it. It is also sometimes soaked in gasoline. After drying and installation, it is important to wet the filter with oil, which is used in a mixture with fuel.

It is very easy to fix the problem of stalling lawn mowers immediately after starting. It is enough to adjust the carburetor according to the scheme given in the documentation. Sometimes you have to loosen the carburetor valves in order to facilitate the supply of the mixture into it.

Sometimes the lawnmower stalls due to the large amount of air entering. In this case, it is necessary to increase the engine speed to release it. It is also imperative to check the fuel hose for possible damage. If necessary, change it to a new one.

It is important to keep the gearbox clean and its gears must always be treated with special grease. It is worth noting that it is not always possible to repair the gearbox and starter on your own, therefore it is more advisable to replace them with new ones in case of breakdown of these units.

When reducing engine power, pay attention to the exhaust muffler, or rather, to the mesh in it. It can become clogged with soot from burnt oil. This malfunction is solved by cleaning the mesh. This can be done using a small wire or nylon bristle brush and compressed air.

Clutch in lawn mowers can riot salespeople due to worn pads or broken springs. In both cases, defective parts are replaced. Sometimes the clutch becomes unusable, it can also be replaced with a new one. over, on sale there are both fully assembled couplings and individual elements for them (washer, drum, etc.).

Symptoms of common problems

Knowing the internal structure of lawn mowers and the principle of its operation, you can easily troubleshoot with your own hands. Some breakdowns are most common and are distinguished as the main ones.

  • Engine malfunctions should be looked for if the mower does not work or does not even start. It is also worth paying attention to this part of the braid if unusual noises or strong vibration is felt during operation. A clogged air filter can also cause engine problems.
  • If fuel does NOT enter the combustion chamber, then you should look for the cause in the clogging of the fuel filter. It is also worth looking at if the tool does not work at low speeds.
  • There are sparks. This is often the case if fuel is flooding a candle.
  • The lawn mower bar vibrates strongly, making it more difficult to work.
  • The reducer is too hot for a short time, which is felt during the operation of the spit.
  • Low rpm turns the line poorly, affecting performance.
  • The starter grille is clogged. Cause of engine overheating and shutdown. The starter can also fail when the cord breaks when starting too abruptly.
  • Carburettor clogging can be due to the use of poor quality fuel. It is also important to pay attention to the carburetor in time if the mixture flows.
  • The lawn mower stalls after shutdown if the carburetor setting is incorrect.


Petrol trim tabs are simple. The main element of the tool is a two-stroke or four-stroke internal combustion engine. It is connected by means of a gearbox with a shaft, which transfers the force to the cutting element. The wire connecting them is hidden in a hollow rod. Also next to the engine are the carburetor, air filter and starter (starter).

The lawn mower cuts the grass with a fishing line or knife, which are capable of rotating at a tremendous speed of 10,000-13,000 rpm. The line is mounted on the trimmer head. The section of the string is 1.5 to 3 mm. The main disadvantage of this type of cutting element is its rapid wear. In total, you have to rewind or replace the line, sometimes this is done by changing the bobbin.

The fishing line is most often used when mowing grass, and for removing shrubs and dense thickets, it is better to give preference to knives (disks). They can be of various shapes and sizes.

The knives and the gearbox are covered with a protective cover, which ensures safety during work. It has special holes through which grease is supplied. To make the mower more comfortable to use, it has a strap with a fastener. It allows you to evenly distribute the weight of the unit, making it easier to work with it.

A handle is attached to the Lawn Mower Bar, which has buttons and levers for control. The handle can be U, D or T. The two-stroke lawnmower uses a mixture of petrol and oil to refuel. It must be poured into the fuel tank.

General recommendations of specialists

Avoiding repairs and contributing to the long service life of your mower is a snap. The first thing to start with. This is a familiarization with the instructions before work. It is important that when the lawn mower is in operation, keep an eye on how well the engine is cooled. Be sure to keep the starter and cylinder ribs clean. Otherwise, the engine can quickly deteriorate due to overheating.

Read more:  How Does A Robot Lawn Mower Work

Periodic engine maintenance can significantly extend the life of your lawn mower. It consists in constant inspection and cleaning of the engine. To wash a cold engine, a soft bristled brush is taken. She needs to remove dirt from the surface. AND.

Fuel must not be left in lawn mowers for periods longer than 30 days. If the mower is idle without work, it is better to drain the fuel mixture. For most tools, 92 gasoline is suitable, which in no case should be replaced with diesel fuel or gasoline with a lower octane number. It is best to use two-stroke engine oil in the mixture. It is not recommended to make fuel compositions for future use, as they eventually lose their initial properties and can lead to damage to lawn mowers.

At the end of frequent use of the spit, for example, with the arrival of late autumn, the lawnmower should be prepared for storage. First you need to drain the fuel mixture and then start the engine. This is necessary so that the remaining mixture in the carburetor is used up. After that, the unit is thoroughly cleaned of dirt and stored. If you follow the lawn mower correctly, then even the Chinese one can show high performance for a long time.

How to repair lawn mowers, see the following.

Chainsaw engine won’t start

If the mechanism does not start, immediately stalls, check sequentially:

  • Is there fuel in the tank;
  • Serviceability of the spark plug;
  • Air and fuel filter cleanliness;
  • Cleanliness of breather and exhaust port.

It is necessary to make sure that the candle is working, giving a spark when it comes into contact with the body. In this case, it is necessary to dry the candle channel, clean and dry the same part. You can change the candle, but the channel still needs to dry for 40 minutes. Check the serviceability of the high-voltage wire, there may not always be a contact. Malfunction in the ignition unit when repairing lawn mowers, do not fix it yourself.

If the air filter is removed and the engine does NOT stall, the reason is in it. Replacement or cleaning required. Replacing the fuel filter is done with great care. Then check the cleanliness of the breather, remove the muffler mesh and clean the exhaust channel.

The next step will be to repair the carburetor, where you have to find the malfunction and fix it, taking into account the tiny size of the parts. If the simplest operations have not yielded results, in order not to disrupt the fine tuning of the system, it is better to entrust the repair to a specialist. Where to start diagnostics and how to properly repair lawn mowers with your own hands, check out:

Is it possible to repair lawn mowers yourself?

At first glance, a simple device for mowing grass with a two-stroke engine is fine-tuned. Repair of lawn mowers must be entrusted to a specialist or study the technique using the operating instructions. The streamer maintenance is essential. Gearbox lubrication, line replacement, teeth sharpening can be done on our own.

Repair and lubrication of the lawn mowers gearbox

The role of the reducer is to transmit the torque from the motor shaft to the cutting tool through 2 gears with different numbers of teeth. The torque is transmitted at an angle of 30 0. The number of revolutions of the lower cutting blade is 1.4 times less than the engine speed. Gears Must be clean and lubricated. To supply oil to the teeth, there is a hole under the screw on top.

First, the place where the plug closes the hole should be cleared of soil and grass. Unscrew the plug with the appropriate tool, it is included with the saw. We use a grease tube. Either a native lubricant from the manufacturer is selected, or well-known high-quality compounds such as Oleo-Mas, Litol.24, Azmol 158. We open the protective layer of the tube and Lay the instrument on its side. Slowly rotating the knife, squeeze the grease into the gear housing. The gears, turning, carry the composition with teeth over the entire surface. You can also pour grease with a special syringe.

Insufficient or too much lubrication can cause the gear unit to heat up. A knock and backlash is heard, signaling the destruction of the bearing or the ingress of dirt due to damage to the anthers. Bearing replacement must be done with a Puller and not using the warm-up method.

If the gearbox staggers and runs on the rods, it is necessary to replace the housing, or temporarily tighten the knot with a clamp to fix it on the pipe. If the knife stops turning, then the gears are NOT engaging. Teeth worn or chipped. You will need to replace a pair with a complete parsing of the assembly.

When replacing a gearbox, it is necessary to select a new unit, guided by:

  • Pipe diameter;
  • Drive shaft diameter;
  • Cross-section of the drive shaft;
  • Method of fastening protection

Lawn mowers malfunctions and how to fix them

Any type of lawn mower has a hollow rod, in which a connecting cable is placed between the motor shaft and the lower gearbox, transmitting rotation to the working body with the cutting tool. In the upper part there is a carburetor and a motor, at the bottom. Gearbox and working tool, covered with a casing. In the middle part there is a transverse handle in which the control buttons are located. For unloading the arms, there is an unloading belt that holds the bar with the operator’s torso.

They follow this, the repair of lawn mowers is to troubleshoot;

  • The engine does NOT start;
  • The cutting mechanism does NOT pick up speed;
  • Engine stalls;
  • The reducer is heating;
  • An extraneous knock is heard, strong vibration of the bar.

Before eliminating the malfunction, you need to diagnose, determine the non-working unit.

It is important to know the lubrication points of the tool. Constant care, cleaning the device after work will extend its life. Before work, it is necessary to tighten the fastening bolts, prepare the fuel and fill the tank.

Caring for the cutting unit of the lawn mower

The saw headset dulls or wears out over time. Working with the tool becomes tense, the load increases, the swath quality deteriorates. Metal saw blades sharpen, plastic ones change.

If a fishing line is used as a cutting tool, it gradually wears out, and new material is installed in the spool. The principle of operation of the cutter with a line is to gradually unwind the coil under the influence of centrifugal force. On contact with the grass, the fishing line is abraded; it is fed from the reel gradually. A special winding is needed so that two cutting elements come out at the same time and do NOT get confused with each other.

Read more:  How to Change the Einhell Lawn Mower Attachment

The illustration shows how to properly wind the line around the reel of the lawn mower. Before winding a new line, you must:

  • Having unscrewed the nozzle, carefully remove the cover, holding the spring with your hand;
  • Remove scraps of old fishing line from the reel;
  • Measure 5 meters of a new string and fold it in half;
  • In the reel, guides for 2 ends, hooks with the middle part along the groove and wind in the direction of the arrows for each half of the string;
  • Pass the remaining 20 cm through the special grooves at the opposite ends of the coil;
  • Install the spring and washers, bring the ends of the line out, close the drum with a lid.

In order to better understand how to change the line for lawn mowers, see.

Lawn mowers malfunctions and how to fix them

Possible malfunctions in the automated electric drive are summarized in the table.

Table 14- Possible malfunctions

When the main switches are turned on and the control circuit breaker and the protection button are turned on, the line contactor will NOT operate.

Control circuit fuse blown.

But not all controllers are in zero position.

There is no contact in the chain of zero cam elements. Line contactor coil burned out. Maximum relay contact broken.

Replace the fuse; in case of repeated combustion, find the short circuit and repair. Set controllers to zero position.

Elimination of malfunctions in devices.

When the safety button is released, the line contactor is disconnected.

Faulty auxiliary contacts of the line contactor.

Broken contact in the circuits of the limit switches.

Elimination of malfunctions in devices.

When the controller handle is moved to the first operating position, the protection is triggered.

Short circuit in the armature circuit, at the output terminals.

Blown fuse in the control circuit.

A fault in the limit switch circuit is checked by the possibility of operation in the opposite direction of movement.

Checking the absence of a short circuit.

Eliminate short circuit and replace fuse.

Eliminating the fault in the limit switches.

When the handle is moved to the first working position, no movement occurs.

Open in the power circuit.

Open brake circuit.

Mechanical brake does not release.

Check continuity.

Check the voltage at the brake coil.

Eliminate jamming in brake assemblies.

End protection does NOT trigger.

The electromagnetic device does NOT turn off, in the coil circuit of which the limit switches are turned on.

Limit switch misalignment or mechanical failure.

Check the absence of welding of the contacts of the line contactor or bypass power supply circuits of the zero relay.

Adjust the switch in case of breakage. Replace.

There is no voltage at the input of the power section of the control panel and at the input of the converter.

The circuit breaker on the water of the electric drive or in the control circuit is faulty. Line contactor does not turn on.

Check the circuit breakers with an ohmmeter, repair or replace if necessary. Check the closing circuit of the line contactor. Check the installation of the handles of the controllers in the zero position.

When the converters are turned on, there is no voltage at the input.

Defective circuit breakers in AC power or control circuits.

Check circuit breakers, troubleshoot.

Circuit breakers are working properly, but there are voltage comments at the output of converters.

There are no thyristor control pulses due to poor contacts in the adapter plug connectors.

Use an ohmmeter to check the reliability of the contacts and eliminate the malfunction.

Transient plug connectors are OK and there are no output pulses.

Vs voltage on power and synchronization transformers.

Check for faulty power supply circuits of transformers.

Starting and braking modes are not smooth.

The rates of change of the output parameters of the converters are NOT adjusted.

Adjust the rate of change of the output parameters of the converter with the adjusting potentiometers.

The speed relay is working correctly, and the voltage at the output of the inverter does not match the specified.

The voltage at the output of one of the phases of the power rectifier of the converter is NOT regulated due to the lack of contacts in the plug connector of the ERMS board. One of the SPFU channels or the power supply unit of the control system is faulty.

Check the contacts of the plug connector. Identify and eliminate a malfunction in the phase-pulse control system.

Measuring the voltage at the contact sockets of the control system power supply.

The electric actuator is NOT reversed when the controller handle is moved from the position up into position down or back.

Control pulses DO NOT switch from one thyristor bridge to another due to a malfunction of the LPU or the power supply bridge of the LPU circuits.

Check the operability of the LPU and replace the faulty transistors and diodes in the unit. Identify and replace faulty power bridge diodes.

The power rectifier is working normally, but the speed of the electric drive does not match the specified, high currents of the armature circuit.

The exciter does not work correctly due to the lack of contacts in the plug connectors, a malfunction of the phase-pulse control system or the power supply.

Check the reliability of the contacts. Identify and eliminate faults in the pulse-phase control system or power supply.

The specified range of speed regulation is NOT provided when working with loads weighing less than the nominal.

The maximum lifting and lowering speeds of the empty hook are NOT reached.

Two-current relays are NOT adjusted, which switch in the channel of the Surva panel to provide a constant power mode.

The value of the minimum exciter voltage is set incorrectly.

Adjust the two-current relays in the modes of lifting and lowering the electric drive.

Check Surv’s job chains. Adjust the value of the minimum exciter voltage.

The electric drive is unstable. Variations in motor speed, voltage and current are observed.

The power rectifier current and speed regulators and the field current regulator are NOT adjusted. Defective current and voltage sensors.

Adjust the regulators. Check and repair sensor circuit faults.

Increased heating of the motor bearing.

Development in bearing cages or balls.

Not enough or too much grease in the bearing.

Adjust the amount of grease in accordance with the standard.

Brushes installed incorrectly.

The brushes are in poor condition.

The collector is dirty due to the use of too soft carbon brushes.

Check the position of the brushes according to the factory marks on the Traverse.

Grind the brushes carefully to the collector.

Wipe down and grind the manifold. Replace brushes with harder ones.

Lawn mowers malfunctions and how to fix them

Technical malfunctions and ways to eliminate them
Our company supports the service and repairs the following equipment: power plants, gas generators with power from 700W to 10kW with HONDA, B engines S, diesel generators with power from 2kW to 300kW air and liquid cooling with engines YANMAR, HATZ, DAIHATSU, ISUZU, KAMA, CUMMINS, PERKINS, VulVO, etc.

This section was created for users of technology, engineers and mechanics for the repair of gasoline equipment and power plants. Here displays information about power plant breakdowns, the reasons for their occurrence, warranty and non-warranty cases, methods of eliminating technical faults that our technicians had to deal with.

To the attention of professional service technicians! We understand that all of the following cases are private and many breakdowns may occur Not only for the reasons stated below. These are the malfunctions that are contacted by our service. We will be happy to share our experience with you and post with us your faults and your methods of diagnosing and repairing them.

In order to maximize the effectiveness of this section, we urge you to report any faults, auto products when using the power plant, to our specialists by email, or to our company office. We will try to be as useful for you as possible.

Each case is always individual and often consists of several malfunctions, therefore, to troubleshoot a malfunction, it is necessary to take a comprehensive approach. If in the description below the specific case does not indicate that there is mechanical damage to units, parts, and the structure of the power plant, then a case is described when in reality they were NOT. All of the information below can be used to diagnose a problem and correct it yourself. However, in case of self-opening of the engine, or other units of the power plant, the equipment will void the warranty. All technical work has the right to be carried out only by certified specialists for a specific equipment manufacturer.

Ignition system malfunctions

If the symptom is a poor start of the engine, then there is a possibility that the problem lies in the incorrect setting of the fuel ignition system. The following cases are common:

  • The chainsaw shoots the carburetor.
  • The chainsaw shoots the muffler.

There are cases when recoil appears when starting the chainsaw.

Consumables can be called candles. They can often fail, and also indicate some other reasons for the malfunctioning of the device. The main features include:

  • If fuel does NOT enter the carburetor, the surface is dry. The problem may be in the filter or deformation of the supply pipes.
  • Filled with fuel indicates improper operation or carburetor setting.
  • If the surface is covered with carbon deposits, then the problem lies in the use of low-quality oil, as well as improper fuel mixing and carburetor settings.

Electronic ignition on a chainsaw

With prolonged operation, the candle itself may fail, which it is enough to replace with a new one.

Fuel supply system malfunctions

Gasoline does NOT flow into the chainsaw carburetor when the spark plugs are dry. Common causes of such a malfunction include:

  • The installed filter is heavily clogged. In order to eliminate the likelihood of a large amount of harmful impurities entering the cylinder block, a filter is installed. The filter can be cleaned in case of strong clogging; it is replaced from time to time.
  • Fuel supply may be interrupted due to severe blockage of the installed breather.
  • The carburetor setting is changed frequently. In this case, the assembly is re-adjusted to ensure a stable fuel supply.

Chainsaw filter replacement

The ideal proportion of the fuel mixture is indicated by the manufacturer in the operating instructions. In most cases, fuel is NOT supplied due to clogged passages and filter elements. Therefore, you need to monitor its quality.

Carburetor adjustment

In many ways, the operational life of a structure depends on the quality of the assembly. Quite often, there are problems with a Chinese chainsaw associated with wear of the main elements. The low cost of the proposal is due to the introduction of low-quality materials.

There are several main signs that you need to adjust the carburetor:

  • Strong vibrations occur at the time of work.
  • Worn out CPG.
  • There are signs of mechanical damage to the protective cap.
  • The engine switches itself off or is almost impossible to start.
  • Fuel consumption and exhaust emissions increase unnecessarily.
  • A sharp drop in the power indicator.

Adjustment recommendations for the element in question are provided by the device manufacturer. As a rule, adjusting screws are placed with a protective cap, which allow you to adjust the operation of the chainsaw.

Often problems with operation arise due to changes in the settings of the fuel supply system. The safety precautions for troubleshooting carburettor require no fuel. The whole procedure can be divided into two main stages:

  • Base.
  • Finishing.

To begin with, the position of the screws H and L is changed to the stop, after which they are turned back by 1.5 turns. The finishing stage provides for heating the internal combustion engine for 10 minutes, since some characteristics change during heating. The adjustment is carried out using a special screw, which is set to the position to reduce the speed. The chain must be stationary.

Typical types of chainsaw malfunctions

There are just a huge number of different types of chainsaws on sale, most of them have approximately the same design and technical characteristics. Possible chainsaw malfunctions are as follows:

  • Deterioration or failure of the engine.
  • Malfunction of the installed fuel supply system.
  • Problems with the system responsible for the removal and extinguishing of gases generated during fuel combustion.
  • Severe wear or malfunction of the system responsible for supplying lubricant to the chain.

Maintenance intervals and many other points are indicated by the manufacturer in the operating instructions. It should be borne in mind that improper use of the tool and violation of basic recommendations often leads to serious malfunctions of the chainsaw.

Muffler problems

Some chainsaw breakdowns are associated with improper exhaust of gases, which are generated when burning fuel. Examples include the occurrence of a large amount of smoke at high speeds, as well as unstable operation. Due to the large amount of carbon deposits and mechanical damage, the throughput of the muffler is significantly reduced. Cleaning from carbon deposits is carried out as follows:

  • Carry out dismantling, which necessarily closes the outlet.
  • The muffler can be disassembled and its internal condition checked. However, in some cases, the structure is non-separable.
  • You can clean the inner space from carbon deposits with the help of Special substances. Less commonly, the dry method is used, involving mechanical action.

Cleaning the chainsaw from carbon deposits

After cleaning the structure, it must be thoroughly dried. You can speed up drying with a construction hair dryer. When reassembling, open the outlet.

Chain lubrication system malfunctions

In order for the device to work for a long time, as well as to simplify the sawing process, chainsaws have a special lubrication system. It is powered by an oil pump, which from time to time may fail. The lubrication system can be checked as follows:

  • Filled with special oil.
  • The chainsaw is placed near a vertical surface.
  • The saw turns on and the speed rises slightly.

Correct chain lubrication requires little lubricant spread.