Lawnmower Repair And Maintenance

Lawn mowers are a convenient technique that allows you to maintain grass cover in a tidy condition in the country, in the garden, in the park. Thanks to their use, lawns acquire an attractive appearance with minimal labor and time. Gasoline and electric devices are popular, pushing into the background mechanical models of mowers.

With proper operation, the equipment is able to work for more than one year without breakdowns. But over time, the parts wear out or an unexpected accident may occur, as a result of which the unit will fail. If the technique not under warranty, it is not necessary to contact a service center for help from specialists. Repair and maintenance of lawn mowers can be done at home. This is due to the fact that many malfunctions do not belong to serious breakdowns, they can be quite easily eliminated independently.

Major malfunctions of electric and gas mowers

Despite the variety of models and manufacturers of lawn mowers, gasoline and electric equipment have similar structural components. The difference lies in the types of engines installed and their associated performance systems. Equipment failures are conventionally divided into 2 groups:

  • mechanical;
  • associated with the drive part.

Damage to the mechanical part of models with gasoline and electric motors is almost the same, but a failure during the operation of the drive part of the lawn mower can be caused by problems with different parts.

Lawnmower Repair And Maintenance

Mechanical issues

The mechanical system of lawn mowers with different drives consists of the following structural elements and components:

  • knife (rotary or cylindrical type) or fishing line;
  • gear mechanism;
  • grass catcher and grass ejection devices;
  • wheels, handles and cases.

Failure of the cutting element

Knives are most often damaged (for example, bent) or dull, the fishing line ends. It is easy to detect with simple visual inspection.

The fact that the cutting nozzles are dull is evidenced by the uneven cutting of grass stems when mowing a lawn mower.

With time fastening knives may weaken. Their balancing during rotation is disturbed, and vibration, whistling, and rattling appear. If the knives are damaged, then during operation the mechanism will begin to make in addition uncontrollable, sudden, sudden movements. To troubleshoot this kind of cutting elements put in the right position, replace with new or repair. If possible, the blades are re-sharpened.

Sounds and vibration at work

Uncharacteristic sounds, vibration, and rattling appear during operation of the unit, when the fastenings of its structural elements: the case, engine, are loosened. These phenomena are more common in gasoline models, because their motor fluctuates more during operation than the electric motor. To eliminate these phenomena, check all connections, tightening the bolts if necessary. It happens that the whistle during operation of the unit occurs due to ingestion foreign object, which blocks the roller in the aerator. In this case, just enough to get it so that the sound ceases.

Cutting nozzles do not rotate

Often when mowing tall grass or hard grass, the cutting nozzles stop rotating due to grass clogging. This problem in most cases (if it did not lead to more significant negative consequences) is easy to solve with your own hands, just picking out the stems of plants with a stick.

Breakdown of structural parts

Damage to wheels, handles and casings is rare. If they are significant, then these structural elements change. Repair methods, if possible, in each case depend on the material of the broken parts. they can be plastic, aluminum, steel.

Belt break

With prolonged use, the mower wears out, stretches, and then the belt breaks. At the same time, the gasoline engine of the device works, and the knives do not rotate. Self-propelled models can also break wheel drive belt: then they stop and do not go. Sometimes the clutch cable simply stretches and needs to be adjusted.

Frequent Drive System Problems

The drive part in electric and gasoline-powered mechanisms is arranged differently. In this case, the engine is its main element. Failures associated with the motor are accompanied by the following malfunctions:

  • the mower stops starting;
  • after starting, the equipment stalls almost immediately;
  • during operation, engine power does not fully develop;
  • excessive vibration during operation.

A collision with a stone, stump or other solid obstacle may damage the shaft on which the knife is mounted, as well as the nodes associated with it. Then more radical repairs will be needed.

In most cases, you will need to contact a service center for help.

On gasoline mowers set two-stroke or four-stroke internal combustion engines, having a different design. For this reason, problems with the motor can be caused both by the breakdown of identical parts, or different. Regardless of the manufacturer, the repair of lawnmowers with the same type of installed drive is carried out in a similar way.

Motor Diagnostic Tools

To identify problems with lawn mowers with a different type of drive and to eliminate them, you will need such devices and tools:

  • indicator screwdriver;
  • multimeter or tester with voltage indication;
  • screwdrivers;
  • open-end wrenches or hex keys (depends on the fasteners used in the assembly of the equipment);
  • pliers;
  • nippers;
  • knife;
  • hammer.
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From materials you may need insulation tape and revealed during the inspection details.

The causes of engine mower breakdowns are related to the following factors:

  • overheating or overloading the motor;
  • poor contacts or breaks in the electrical circuit (electrical models);
  • violation of the supply of fuel or oil (for gasoline units).

Therefore, it is necessary periodically, focusing on the recommendations set out in the operating instructions, make stops while working and constantly clean grass residues from equipment.

For internal combustion engines, a suitable oil and the grade of gasoline indicated in the passport should be used.

Identification and elimination of problems with the operation of electric motors

To find out the reason why the electric lawnmower does not start, stops after turning on or during operation, the following measures are performed sequentially.

  1. Check mains voltage on its compliance with the value given in the equipment passport. If it is above or below the norm, you will need to use a stabilizer or stop working for a while.
  2. Visually inspect cord with plug (and a fuse in it) for mechanical damage, and if detected, change the cable or connect it and isolate it again.
  3. Then move on to power button: It is disconnected and checked using special tools.
  4. Inspect for swelling or oxidation. capacitor.
  5. After proceeding to check electric motor lawn mowers: visually check the presence of burned sections of the winding or with the help of the device its integrity.

After identifying at any stage of the breakdown and its elimination, check the operability of the equipment as a whole. Instead of a damaged plug, a new one is definitely installed. The integrity of the power cord and the operability of the on / off button can be easily determined using a multimeter or tester (even a screwdriver indicator).

Go straight to checking phase shifting capacitor recommended with the following signs in the operation of the unit:

  • at the moment of voltage supply, the electric motor twitches;
  • the electric motor overheats at idle or at an insignificant level of load;
  • an uncharacteristic buzz emanates from the motor;
  • the electric motor is not gaining momentum.

A failed capacitor is replaced with a new part of the appropriate capacity.

Visual signs that electric motor burned out, is the blackening of its windings, the melting of their insulation, the fusion of copper. When such phenomena are present, you will need to replace the electric motor yourself or consult a professional. If there are no external signs, and the multimeter shows the presence of a gap in the winding, then you will also need to change the motor.

In the collector models of electric motors, brushes are immediately checked: they are cleaned with sandpaper or replaced.

With years of use, mowers can worn brake pads electric motor. In this case, you need to disassemble the electric motor and remove the linings.

When starting to search for the causes of failure, it should be borne in mind that equipment equipped with electric motors has problems with starting and operating the motor mainly due to poor contacts in the electrical circuit or a violation of the integrity of the wiring. Much less often, a start button, a phase-shifting capacitor or an electric motor breaks down (due to overload or overheating). A number of mower models are equipped thermal motor protection. it can work, while the mechanism will not turn on. To fix the problem, just close the circuit.

Video: Lawnmower Repair And Maintenance


All work operations with electric models of lawn mowers are recommended to be carried out with disconnecting them from the network, so as not to get an electric shock. When repairing an electric motor and a do-it-yourself control system, you must have a basic understanding of electrical engineering in order to properly perform the job.

Causes of Gasoline Engine Failures

Gasoline (especially four-stroke) internal combustion engines are designed to work in areas with a slope of no more than 15 degrees. Short-term 30 degree warps are allowed. At large inclines the motor may stall. Some models of mowers have a gas lever: you need to set the ignition on the lawn mower to maximum before work.

DIY repair of an internal combustion engine is considered a more difficult task than an electric motor. This is due to the greater complexity of its design. You need to know the design of two-stroke and four-stroke engines, their design features.

Starting repair work, you should check the progress of the cable of the bracket (lever) of safety. You may need to adjust it.

Fuel mixture problems

The simplest causes of problems with a gasoline unit are the lack of fuel. Check its availability is not difficult. You should also look at four-stroke engine models condition and oil level. If it is contaminated or small, then you need to fill in a new liquid, draining the old one before that.

During continuous operation of the mower, the carburetor is polluted by the products of fuel combustion or due to the low quality of the gasoline being poured. As a result motor revolutions float. You can clean the carburetor assembly yourself. To do this, it will need to be disassembled and washed with a special tool. You can try blowing air initially to remove clogging.

It should be remembered that before installing in place, the carburetor must be adjusted. For the motor to work well, it must be properly configured.

The fuel hose is also clogged with poor quality gasoline. When it does not enter, the saloon is cleaned with a needle and the fuel filter is replaced. When clogging the air filter engine power drops. In such cases, the filter element needs to be cleaned or replaced.

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Starter cable break

Often, starting problems are caused by a broken starter cord. In the simplest version, repairing the starter consists in tying the rope with a knot. In more complex situations, you will need to disassemble the entire assembly and change the cord.

Spark plug failure

If the gasoline engine does not start at all or stalls immediately, check the spark plug. It should give off a spark visible even in daylight. To do this, it is twisted and inspected. If there is no spark, replace the part. By the appearance of the candle, you can diagnose a breakdown:

  • if it is dry, then this indicates a problem in the fuel supply system;
  • when the candle is wet, malfunctions are caused by improper operation of the carburetor;
  • if there is black soot on the candle, it is cleaned or replaced with a new one.

Other breakdowns

Partial gasoline engine malfunctioning wear or burnout of pistons. For repair, you will need to disassemble the engine and put in whole parts. May also occur mechanical breakdowns, for example, jamming of the crankshaft or piston, cracks in the carburetor or motor housing. In such situations, you will need to install new parts.

Serious repairs of gasoline engines require professional knowledge and skills. If they are not available, then it is best to contact a service center with specialists.

Diagnostics of the cutting part

With constant use of the mower, its cutting tip becomes dull over time. The following symptoms testify to this:

  • grass cover unevenly mowed;
  • plants burst with the root;
  • increases the time spent on work;
  • increases fuel or electricity consumption.

When these phenomena appear, the cutting part must be inspected and, if necessary, removed, having previously been cleaned of grass scraps. If there is cracks in metal or deformations that do not allow balancing of the blades, you need to replace the cutting nozzle. When the wear of parts is negligible, then the sharpening of the knives. It can be relatively easily produced at home with your own hands.

To remove the knife rotor or cylindrical type, and then sharpen it or install a new one, perform the following preparatory activities:

  • drain the oil;
  • electric lawn mowers are disconnected from the mains, and on the petrol units a button is pressed to block their inclusion;
  • from units running on gasoline, fuel is drained or completely developed, the spark plug is twisted;
  • put the mechanism on the supports, allowing free access to the cutting nozzle.

The latter is only necessary if the instrument internal combustion engine installed. You can also tilt this equipment towards the handles by first removing the grass catcher from it. Models with an electric motor can be repaired in any convenient position.

If there are no special tools to lock the shaft, then you need to do this in another suitable way.

Before work, it is recommended to wear tight gloves to protect your hands from possible cuts on the blade.

Removing and installing the knife

Cutting nozzles rotary type on most models they are bolted to the drive shaft. It is located in the center of the part. Replacing a knife on a lawn mower in this case is as follows:

  • in the presence of fragments of grass, remove them with a broom or brush;
  • unscrew the fixing bolt with a suitable size wrench (usually this is number 19);
  • they put the knife (the same length as the removed one) in the correct position, tightening the fixing bolt with the key with the required force according to the instructions;
  • check the uniformity of rotation of the nozzle by twisting it by hand: the distance from the deck should be constantly the same;
  • put the unit in working position.

When the bolt cannot be unscrewed with a wrench, you can lightly tap it with a hammer. If this does not help, then you should pour fasteners with kerosene or brake fluid. It is necessary to use additional levers with the key with caution, because you can break the top of the bolt. The heating of the fastener also contributes to its unwinding.

There are rotor-type knives with two short nozzles. In this case, the replacement work is performed in a similar manner. Change cylindrical knife it is possible according to the same scheme. The difference lies in the design features of the attachment of this type of nozzle.

Remove the cutting tip carefully so as not to lose parts. In this case, you should remember its position so that the new blades are put correctly.

Blade sharpening at home

You can sharpen knives from a lawn mower yourself using the following tools and accessories:

  • grinders;
  • grinding machine;
  • file;
  • sand paper;
  • oselka (bar) or abrasive stone.

Before sharpening should put on gloves. If the work will be performed on a grinding machine or using an angle grinder, you need to use a mask or glasses to protect your eyes from abrasive particles or metal.

Before sharpening the knife, it is inspected for deformations and the degree of wear. Existing bends are aligned with a hammer on the anvil or piece of rails.

At work on the grinder the cutting nozzle is brought to a rotating circle and the blade is leaned against the emery under a certain inclination. To align the edge, a coarse circle is initially placed. Finishing and grinding is performed on a fine-grained circle. If possible, then grind the part with a felt wheel. it is intended for polishing. Some machines are equipped with devices that allow fixing the workpieces. this facilitates the sharpening process.

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Sharpening knife blades using hand tools or grinders recommended by pre-clamping the nozzle in a bench vise. If the cutting edge of the working nozzle is badly damaged, then it can be cut, but only on both sides at once. In all cases, strong efforts should not be made. As a result, the blades should be sharpened at an angle of 30 degrees.

After turning check blade balancing. To do this, insert, for example, a screwdriver into the hole for the bolt. Then raise it to a vertical position: the knife should remain in the horizontal plane. When a skew occurs, a disturbed balance should be restored. This is done by simply grinding the metal from the heavier (outweighed) side of the nozzle. The removal of layers of material is performed little by little, checking the balance.

Replacing fishing line in a lawn mower

In addition to knives, a fishing line can be installed on the lawnmower. Such a nozzle is a coil on which is wound kapron thread. Coils mounted on mowers come in two varieties:

  • with 1st antennae;
  • with two protruding ends of the nylon filament.

The structure of the nozzle is simple: there are two sections in the coil, between them there is a partition, in which there is a recess. Thread wraps around these tracks. For its output from the coil, special holes are provided.

On different models of lawn mowers, cutting nozzles with different fishing line thicknesses are used. This parameter lies in the range of 1.2-4 mm.

In addition, the polyethylene thread varies in sectional shape. This determines the area of ​​use (purpose) of the material. According to these criteria, the fishing line can be of various types:

  • round, which is the most durable variety used for mowing grass;
  • curly, used when mowing plants with soft stems;
  • twisted, suitable only for thin grass stands.

There is a cord professional type. But this variety is not suitable for use on all models of equipment.

The nozzle itself is rarely damaged, it only wears out and the capron thread ends. To resume work, you need to rewind the fishing line. It’s worth buying a thread that is suitable for a coil mounted on a lawn mower.

The procedure for replacing fishing line in a reel with a single antennae

To change the fishing line of a reel with a single antennae released, proceed as follows:

  • turn off the mower, while disconnecting the electric one from the network;
  • remove the cutting nozzle, previously locking the shaft from turning, for example, using a screwdriver;
  • disassemble the housing, usually removing its cover by pressing the tabs;
  • neatly lay out all the details;
  • cut from two to four meters of fishing line with a diameter specified in the instructions for the nozzle used;
  • fold a piece in half to divide it into two identical segments;
  • one end of the cord is threaded into the ear inside the coil;
  • wind the thread counterclockwise (in the direction opposite to the rotation of the nozzle during operation);
  • leave a small end of the thread, which is exposed through the hole, having previously been fixed in a special groove so as not to unwind;
  • collect the coil;
  • set the nozzle on the lawn mower.

When cutting is installed automatic or semi-automatic nozzle cord, inside it there is a spring. Therefore, when disassembling the case, it is necessary to ensure that it does not fly out and is not lost.

The line retaining groove may be missing. In this case, it is held by hand during assembly of the nozzle, so as not to unwind.

Replacing fishing line in other types of reels

To properly reel the line in the reel with two protruding ends of the cord, it is necessary to disassemble it. Inside are two recesses. At the same time, the ends of the fishing line are laid out separately according to these grooves. Winding is also performed in the opposite direction to the rotation of the nozzle.

There are coil models with a different design. In such cases, it is often not necessary to disassemble the nozzle in order to insert the cord. Thread insert into a special through ear, located inside the coil. Winding fishing line is due to the press of a button. It is located directly on the cutting nozzle body and is designed so that when the cord is worn out, its new ends can be released without disassembling the coils.

It is recommended to carry out work on replacing the fishing line on gas mowers with the pressed lock-on button.

Before you wind the fishing line, you can pre-soak it for a while in water. this will increase the strength, as well as the elasticity of the inserted thread. Winding metal cables is prohibited. The cord must comply with the diameter specified in the instructions.

Repair of lawn mowers should only be started after a preliminary review of the instructions for their use. It discusses the design of the model and the rules for its use. To minimize the likelihood of breakdowns, regular maintenance requirements must be followed. It is necessary to apply only high-quality fuels and lubricants.

Before mowing grass, it is recommended to inspect the pre-treated area for stones, stumps and other obstacles. This will help to avoid accidental collisions and unforeseen accidents. Also note that a lawn mower is recommended. work with dry grass, because it slows down clogging knives and other details of the mechanism.