Do-it-yourself repair of lawn mowers: faults and their elimination. Do-it-yourself grass trimmer repair, common causes of breakdowns Repair of brush cutters

Garden plot will not have a neat appearance if bushes have grown in its gardening area and the grass has formed a thick cover. This indicates the neglect of the site by the owner, who does nothing even to mow the lawns. But mowing the grass is the easiest task on the site, because various equipment has been created for this work.

The advantage of a gasoline trimmer

For example, a trimmer is a very convenient and productive, lightweight, reliable and practical device to use. It can be electric, lightweight, or gasoline, with high performance. Gasoline ones are more common, as they have a fuel tank and can operate at a distance from electrical communications. Perhaps the only disadvantage of a gasoline trimmer is that, like any equipment, it periodically breaks down. But in this matter it has an advantage, since for people who understand a little about technology, it is possible with their own hands.

Troubleshooting

If the trimmer stops starting, then you should not immediately sound the alarm and contact the service center, since the cause of the inoperability can be easily eliminated. Any DIY repair of gasoline trimmers begins with checking for the presence of a spark, without which it is impossible to ignite the fuel in the combustion chamber. If there is no spark, then the problem is either in the spark plug or in the ignition itself. An exception is in cases where the spark plug is filled with fuel mixture when the fuel is overfilled above the required level. In this case, you just need to wipe it dry and the treasured spark will appear.

It will also indicate that there is no fuel supply. If it is dry and light brown in color, in this case, repairing a gasoline trimmer with your own hands will involve adjusting the fuel pumping or All these reasons can be easily eliminated, the main thing is that the engine itself works properly. But if the cause of the malfunction is still hidden in the engine itself, then it is recommended to contact a service center due to the complexity of repairs. But for people who can hold a screwdriver in their hands, nothing is impossible. In most cases, trimmer ends successfully.

Briefly about engine repair

Engine problems begin after a few years correct operation from wear of components or suddenly due to improper use of the trimmer. Unfortunately, people regret improper operation when they repair gasoline trimmers with their own hands after an engine breakdown. And this happens in cases where the dosage of oil in the fuel is not observed or the device operates to the point of terrible overheating. Overheating may cause the crankshaft to jam, the piston rings to break, or the piston to completely burn out. In order to perform a piston inspection, it is enough to remove the cylinder head, from under which the piston will appear, clearly reflecting the condition of its working surface. The rings themselves do not protrude from the cylinder, so it does not matter whether you change the rings or the piston, in both cases you will have to remove the cylinder. When repairing gasoline trimmers with your own hands, it is worth remembering that they are fragile and can easily break if you lack experience. Installing the piston itself on the crankshaft is not too difficult. The main thing when repairing an engine is to assemble everything the same way as it was before disassembly, and then everything will work again.

Trimmer malfunction:
The edges on the trimmer drive shaft licked (I had to buy a new shaft).

“Licked” because the shaft splines at the top are not engaged over their entire length (it happens that the shaft only engages a few millimeters at the end). At the bottom, the shaft enters the gearbox its entire length under its own weight.

At the first time The trimmer must be checked and made so that the shaft fits into the clutch at the top for the entire length of the splines (or edges, if they are square). To do this, try to put the gearbox higher on the pipe, having first loosened its fastening, or try to push the pipe deeper into the shock absorber, having first loosened its fastening. If the shaft splines still do not fit the entire length into the clutch, then you need to shorten the pipe (cut off a part) to the length necessary for the splines to fully fit into the clutch.

Warning: Just don’t overdo it with cutting the pipe (it’s better to cut off a smaller piece), because if the shaft turns out to be longer and needs to be cut, then when the shaft splines heat up, the metal will release, i.e. hardened metal will become soft and will not last long (the shaft itself is made of alloy steel).

P.S. If the shaft has already been “licked”, then simply turn it over - install the shaft with the top splines down into the gearbox and do what is described in Do-it-yourself trimmer repair.

Trimmer repair: how to stop lubricant leaking from the gearbox

Trimmer malfunction:
Where does the lubricant go from the trimmer gearbox (Chinese trimmer, instead of a plug, a grease fitting and a syringe were screwed into the gearbox).

Cause of trimmer malfunction:
Solid oil under pressure pressed through the sealed bearings of the gearbox. During operation, liquid hot lubricant, driven by rapidly rotating bevel gears (in a small volume of the gearbox housing), “flies out” either into the driver cartridge if the sealed bearing rings on the driven shaft are pressed, or upward into the pipe body if the sealed bearing rings on the drive shaft are pressed gearbox

Replace the bearings (or the entire gearbox) at a service center and then use a special lubricant for the trimmer gearbox (for example, Husqvarna).

Advice: Chinese lawn mowers have a small hole for adding lubricant to the gearbox, so it would be more convenient to take the lubricant from the branded tube into a medical syringe (without a needle), and then add lubricant from it to the gearbox.

Repair of trimmer Husqvarna 333R

Husqvarna 333R for 3.5 active seasons commercial exploitation(required replacement):

Note: I read somewhere that the time between failures of two-stroke engines is no more than 500 hours, and in 3.5 seasons I burned ~370 liters of gasoline, i.e. if 0.35 l. per hour, then the operating time is already more than 1000 hours! The Husqvarna 333R trimmer is a very reliable trimmer (petrol mower).

Note: Please write in the comments what you think about this trimmer repair.

Petrol trimmer repair: how to replace gearbox bearings

Trimmer malfunction: Tell me how to disassemble the gearbox on the trimmer to replace the bearing (Husqvarna). And does he even understand?

Answer: The Husqvarna trimmer gearbox can be disassembled to change spare parts such as bearings, bevel gears, housing (since the assembled gearbox for a Husqvarna trimmer costs about $150.)
You need to remove it by loosening the tightening bolts at the bottom, be sure to wash it (for example, with gasoline), then use round nose pliers to bring the ends of the locking spacer ring together (there are two of them on the gearbox) and pull out the bearings with a small puller. They should go easily, since the upper bearing is no longer pulled together by the housing, and the drive shaft of the Husqvarna trimmer comes out of the lower one.

Trimmer repair: how to restore the thread in the spark plug hole of the cylinder

Trimmer malfunction: The spark plug is very difficult to screw in.

Cause of malfunction: The thread in the spark plug hole of the cylinder is damaged due to the fact that the spark plug did not follow the thread when screwing it into the cylinder, or sand got on the threaded part of the spark plug, or the thread was torn off by a large force on the key.

If the spark plug is not screwed in deeply, then you can drive the threads in the cylinder with a tap of the appropriate size, then screw in a new spark plug and tighten it with a force of 32-33 N*m. If the spark plug does not turn, then everything is fine, but the next time you turn the spark plug out, you need to be especially careful. If the spark plug turns, you will have to install a bushing (repair sleeve). To do this, it is better to contact a chainsaw repair shop and petrol trimmers. There is necessary tool and qualified personnel to select and purchase (or manufacture) a spark plug repair bushing suitable for your spark plug, then properly disassemble the engine, drill the spark plug hole to the exact required diameter, and cut the appropriate threads in the cylinder. Then rinse everything and blow off any shavings, screw the spark plug into the bushing, apply it to the threads of the bushing thread sealant or cold welding, screw the spark plug together with the bushing into the prepared hole, dry it, assemble everything, start it and adjust it. Another option is to replace the engine cylinder. Repairing a lawn mower yourself is similar to repairing a trimmer.

Advice: The main thing when installing a spark plug is that you first need to tighten the spark plug a few turns BY HAND, and then take the key. If the spark plug comes out easily by hand, it means it is installed correctly and can be tightened with a tool (a spark plug wrench with a knob). If the spark plug does not want to be twisted by hand, you should not tighten it with force with a wrench, since the spark plug has gone the wrong way and the threads in the spark plug hole of the cylinder will inevitably be damaged and an expensive repair of the trimmer engine will be needed.

Repairing a lawn mower: how to cut and change the gasket under the carburetor

Trimmer malfunction: A cold trimmer engine with a closed carburetor air damper starts almost normally, operates at elevated idle speed, when the engine heats up, unstable operation is observed, after which the trimmer engine suddenly stalls. The malfunction of a lawn mower is the same as that of a trimmer.

Cause of malfunction: Air leakage under the trimmer carburetor gasket due to loose carburetor mounting or frequent removal/installation of the carburetor.

Make a new trimmer carburetor gasket from thin paronite (up to 0.8 mm thick) or thick cardboard. How to make a carburetor gasket: cut out a piece of thin paronite or thick cardboard a little larger than the future finished gasket, spread seat on the cylinder or carburetor with oil or grease, carefully apply the prepared piece for the gasket so that a clear imprint of the grease remains on it (the outline of the future gasket). Then cut out the middle with a small sharp narrow chisel on a heavy metal lining (for example, an anvil), cut out the holes with a special head from the kit suitable diameter, and cut the outer part with scissors. As an option, apply paronite or cardboard to the cylinder seat, just do not move it, tap the edges with a mallet, and knock out the holes with a ball from the bearing, but there is a risk of damaging the edges. The first option is how to make the carburetor gasket better. That's it, the trimmer carburetor gasket is ready. Repairing a lawn mower with your own hands in this case is similar to repairing a trimmer.

Trimmer repair: how to replace gears and bearings in the trimmer gearbox

Trimmer malfunction: Trimmer gearbox - hum, grinding, squeaking and other noises in the lower part of the trimmer, jamming when turning and the driven shaft is loose. The malfunction of a lawn mower is the same as that of a trimmer.

Cause of malfunction: The trimmer gearbox bearings have failed due to overheating of the gearbox, lack of lubrication in the gearbox housing, impact of the trimmer knife on a stationary object, and long-term (many years) active use.

Replacing the bearings in the trimmer gearbox yourself (you need keys to remove the gearbox; pliers to remove the retaining rings and disassemble the gearbox; gasoline to wash all the insides to troubleshoot the parts; new trimmer gearbox bearings for replacement) or replace the gearbox bearings in a workshop. If only one trimmer gearbox bearing is destroyed, both bearings still need to be replaced. Or, as an option, replacing the trimmer gearbox assembly - select the gearbox to match the diameter of the pipe onto which it will be clamped and along the splines of the drive shaft (square, star, hex). Repairing a lawn mower yourself is similar to repairing a trimmer.
PS: After replacing the bearings in the trimmer gearbox or replacing the gearbox assembly, do not forget to fill the gearbox housing with lubricant (need good lubrication, for example Husqvarna) through a special hole in the gearbox housing from a tube of lubricant or from a syringe (without a needle) if the filling hole is very small.

Repairing a lawn mower: how to restore functionality to a broken starter spring

Trimmer malfunction: When trying to start the engine, the trimmer starter cord stopped returning to the starter housing. The malfunction of a lawn mower is the same as that of a trimmer.

Cause of malfunction: The end of the spring in the trimmer starter jumped out and the pulley jammed.

Disassemble the starter, drill a hole where there is a recess to fix the end of the spring, thread a wire, insert the spring, lay one turn, tie the wire thus fixing the spring end that has jumped out, lay all the turns of the spring, bend the end of the spring inward to engage with the groove on the other part. Then place the washer, spring, part with two antennae, tighten the central screw, insert the cord through the hole, tie a washer at the end to secure the end of the cord, lay the cord, check the operation of the starter and the return of the cord to the trimmer starter housing. Repairing a lawn mower yourself is similar to repairing a trimmer.

Trimmer maintenance using the Husqvarna 333R as an example to prevent trimmer repairs

THAT. We use trimmers (gasoline mowers) to:

• in the heat and under any load, the trimmer engine did not overheat;
• ensure precise adjustment of the carburetor and, accordingly, optimal performance brush cutter engine;
• identify possible defects, fuel leaks and other malfunctions in order to avoid trimmer repair;
• promptly change the spark plug, unreliable bolts, gaskets and other consumables;
• so that the trimmer (mower) has a good appearance;
• so as not to take the trimmer to a service center.

THAT. We carry out the Husqvarna trimmer after rolling out every 40 - 60 liters. gasoline

(depending on heat, dust and severity of work).

Servicing the trimmer air filter

I wash the air filter after the engine is rolled out every 20 liters of gasoline and before repairing the trimmer or servicing the trimmer.

To service the air filter you need to: remove the foam element of the air filter and wash it with soap and water in a clean and warm water, squeeze and dry (or replace if the foam filter element is old or damaged).

Note: The air filter can be “washed” more often to prevent a drop in power, increased fuel consumption, starting difficulties, and unnecessary wear and tear on the lawnmower engine.

Note: If you adjust the trimmer carburetor with a dirty air filter, then after cleaning the air filter, more air will flow into the engine and fuel mixture will become much poorer, which will lead to poor performance or even engine failure and, as a result, repair of the trimmer.

Preparing for trimmer maintenance and repair

• provide (purchase and dilute) the usual fuel mixture for the operation of your trimmer (for example, A-95 “Mustang” gasoline from a WOG gas station and Husqvarna two-stroke oil, in a ratio of 1:50) and leave 1.5 liters of clean (without oil) gasoline for washing engine parts;
• buy a new spark plug: only Champion RCJ6Y - according to the manufacturer's instructions Husqvarna;
• prepare water-washing supplies for T.O. and trimmer repair (~7);
• prepare petrol-washing supplies (~5);
• buy the necessary Husqvarna bolts and screws to repair the brush cutter (new fasteners);
• prepare thin paronite for the gasket under the carburetor of the trimmer, round fishing line 2.7-3 mm, gear lubricant, clamps, fuel filter;
• provide good lighting, room cleanliness and workplace for repair of the trimmer (baking tray for laying out parts and spare parts, stand for the motor, lining for keys and tools);
• ensure personal performance (if necessary);
• allocate one free day specifically for maintenance and repair of the trimmer (petrol mower).

Beginning trimmer maintenance and repair

1. Add grease to the trimmer gearbox. Remove the metal blade or trimmer head and clean the driver cartridge inside of any grease and soil.
2. Wash warm water and brush everything on the steering wheel, everything on the bar and both protections (the protections of lawn mowers, as a rule, become heavily “overgrown” with a dried mixture of soil and grass juice, so it is advisable to clean the plastic protections with a metal brush, and then washing powder and a brush. Rinse and dry everything.
3. Inspect everything on the trimmer for cracks, bends, abrasions, distortions, tears (especially metal blades at the base of the teeth and at the holes and both protections). Reliably eliminate all faults identified on the brush cutter. Remember! – the thickness of the metal is calculated on a computer, therefore tightening of fasteners must be carried out only in a service center using a special fastener tightening card with a torque wrench. If you do the tightening of the fasteners yourself, then do not overtighten! Because when the gearbox (for example, a gearbox) is heated up strongly in the heat with a heavy load, the metal expands, and there is little thickness reserve and the housing may burst (crack).
4. Install trimmer head (T-35) with 2.7 mm or 3 mm cord standard length(before the cutting blade in additional protection) to load the engine to adjust the high speed needle, that is, the left screw of the carburetor trimmer.
5. Rinse and drain the fuel from the tank into a bottle.

Disassembling the Husqvarna 333R trimmer (procedure for disassembling the engine for maintenance and trimmer repair

1. Remove muffler cover- one bolt.

2. Turn the trimmer over on the table and remove metal pan (three screws).

3. Remove block starter(this is the air intake of the trimmer engine cooling system) - three screws and two rubber bands!

4. Unfasten the air filter cover and remove cylinder cover(it directs cold air to the cylinder) - one bolt.

5. Unscrew the three bolts in air filter housing(one short and two long).

6. Carefully disconnect throttle cable from the carburetor.

7. Inspect so far everything is dirty - the carburetor on the trimmer and its gaskets, hoses, tank, plug for fuel leakage (cracking and leaks).

8. Remove fuel tank with two hoses (disconnected very carefully with a screwdriver) and four support rubber bands (do not lose them).

9. Remove carburetor Zama C1Q complete with air filter housing and gasket.

10. Use a screwdriver to remove choke button(you need to make a mark there for subsequent installation).

11. Turn the carburetor on the trimmer, remove it from the air damper rod on the body and then from the other rod.

12. In the new spark plug Champion RCJ6Y (for Husqvarna) set the gap to 0.5 mm.
Unscrew the old spark plug and install a new spark plug into the trimmer cylinder!
(the old candle - either throw it away immediately, or clean it, set the gap and prepare to wash it in order to hide it in storage).

Note: Due to carbon deposits on the spark plug electrodes: interruptions in engine operation occur (the trimmer engine malfunctions), a drop in power occurs, and the engine may not start easily.

Note: Carbon deposits on the electrodes of the spark plug are formed due to improper adjustment of the trimmer carburetor, if there is a lot of oil in gasoline and when the air filter on the trimmer is dirty.

13. Disconnect shock absorber cap(two side screws).

14. Disconnect barbell from the motor (three end bolts).

15. Remove from the front clutch cover(three end bolts) and inspect the condition of the drum, bearing, clutch spring and weights (check for wear). If necessary, replace it at a Husqvarna dealer, or disassemble it for washing.

16. Disconnect throttle cable(in two places).

17. Separate from clamp and stack spark plug wire and wires to the “jammer”, and disconnect jammer wires on the trimmer motor.

18. It is not recommended to disassemble further, as the factory ignition setting will be disrupted! (let me remind you: our task is only maintenance and repair of the trimmer). Muffler and intake panel It is not recommended to remove it (just check the fasteners!), so as not to break the tightness of the intake/exhaust and to prevent dirt from getting into the cylinder when washing.

19. Loosen one bolt and remove shock absorber from the pipe. Wipe the seat on the pipe dry. Remove the shock absorber cover.

Note: I removed the spark-extinguishing mesh in the muffler to prevent possible overheating of the trimmer engine due to the mesh being clogged with carbon deposits.

Safety precautions: Sparks may fly from a muffler without a spark-extinguishing mesh.
Caution! Do not work where there is dry hay, gasoline or other flammable materials.

Washing trimmer engine parts

20. Prepare at T.O. and trimmer repair:

• photo.bath (empty and clean);
• 1.5 liters of pure gasoline, no oil! (to pour 0.7 liters into the bath twice);
• a narrow brush with long, hard bristles;
• a pump with a purge tip (or a compressor with a receiver);
• large clean rag.

21. In order, wash with gasoline, blow out (!) and wipe painted surfaces with a clean (!) rag, including bolts and rubber bands (5 of them):

• trimmer air filter cover and rubber band;
• carburetor Zama C1Q (with partial disassembly and checking the holes with a thin copper wire);
• carburetor and air filter housing, quickly(!), since gasoline dissolves some types of plastic;
• the tank plug, especially the holes and the tank itself (if necessary, remove it with a hook from a bicycle spoke, remove the fuel filter from the tank and replace it);
• cylinder cover;
• trimmer starter block;
• coil wires on the shaft tube;
• Wrap the spark plug cap in cellophane and place it on the spark plug (then wipe with a dry cloth).
• Thoroughly wash and blow through the disassembled engine (carefully!, as gasoline corrodes the plastic parts of the ignition coil), especially carefully wash the entire engine cooling system!, in order to avoid overheating under extreme operating conditions of the trimmer;
• old spark plug (clean first, if there is one) and put it in storage;
• shock absorber and shock absorber cap;
• disassembled trimmer clutch;
• clutch cover;
• aluminum tray;
• muffler cover;
• wash the bolt heads and rubber bands (there are 5 of them);
• Wash the tray and brush in the remaining gasoline, wipe and hide.

22. Repeat paragraph 21 (selectively).

23. Wash your hands.

24. Inspect all wires and clean connections! (there are three of them?).

25. Open the trimmer throttle handle in half, disconnect the throttle cable and use a pipette to drop oil into the cable casing from both sides of the casing, constantly moving the cable to lubricate it. Clean and reassemble the throttle handle.

The procedure for reassembling the engine when so and repair of Husqvarna 333R trimmer

Note: I will be grateful to everyone who expresses their opinion in the comments about T.O. and repair of a Husqvarna trimmer (or compare with that and repair of a trimmer of another brand).

How to work with a lawn mower (trimmer) correctly

Operating principle and design of brush cutters not much different from any other small petrol garden equipment, for example, chainsaws, motor drills or motor shears. The design of the brush cutter is based on a gasoline 2-stroke carburetor engine with one cylinder (less often a four-stroke), a manual starter and an air cooling system. The engine runs on a fuel mixture of gasoline and 2-stroke engine oil in a ratio of 1:50. The proportion of the fuel mixture may differ from the standard depending on the manufacturer’s individual recommendations specified in the product operating instructions. Always follow the recommended proportion. The mowing accessory for a brush cutter is a mowing drum with a fishing line or a metal one cutting knife, saw. The transmission of engine speed to the mowing unit occurs according to the following scheme: crankshaft – clutch – clutch plate – drive shaft – bevel gear – mowing head (knife).

Basic rules and techniques when working with a lawn mower.

To achieve good mowing results, as well as long-term operation of the equipment, it is important to properly operate and care for the brush cutter. Even if this is your first time holding a lawn mower, correct technique You will master mowing quickly. The device is simply turned in a semicircle from right to left, while gradually moving forward.
Below we will show you the basic technique and some tricks with which you can quickly mow even large areas and achieve best results as a mowing.

The basic mowing technique is the most commonly used.

Since the cutting tool rotates counterclockwise, the most common mowing movement in working practice is from right to left. The advantage of this method: the mowed grass falls onto the already mowed surface.

Large, flat surfaces are the right technique.

Large, flat surfaces are best mowed using the square method. The area is distributed into squares, then you always work along outside to the center.

Basic technique in case of tall grass.

At very tall grass or tough weeds, it is recommended to mow in both directions of movement: first you cut with one movement to the right top part mowed grass, when moving in the opposite direction (to the left) - lower. In this case, the cut grass remains on the left.

Along the slope there is mowing after mowing.

You will get along well with the straight mowing method, especially on a slope: cut one strip parallel to the slope and then work your way back along the cut line. Then mow the next higher crop. And here, the mowed grass is always laid on an already mowed surface.

Masterfully bypass obstacles - mow effortlessly.

To mow close to trees or bushes without damaging branches or trunks, a cutting thread is best suited. If many plants are located at a short distance from each other, mowing is suggested here before mowing. To do this, use the protection of your brush cutter as a guide. Guide it all the time directly along the trunk of a tree or bush, and move around them. The trunk will remain protected and the area around the trunk will be mown.

A haircut. Hold the trimmer head directly above the ground at an angle. The work is done by the end of the string. Allow the string to operate at its own speed. Do not press the line against the area to be mowed! This overloads the engine and mowing head - they can break down or melt!
Cutting. The trimmer is ideal for cutting grass that is difficult to reach with a regular lawn mower. While cutting, keep the string parallel to the ground. Avoid pressing the trimmer head into the ground as this may damage the lawn and damage the tool.
Trimming with a knife. Mow with a pendulum motion from side to side, the movement from right to left will be working, and from left to right will be return. The blade should cut the grass with its left edge (on the clock dial - between 8 and 12).

How to properly prepare the fuel mixture: Fuel = Gasoline + Oil

Oil– high-quality two-stroke oil for high-speed equipment (10-15 thousand rpm, about 200 rpm). Do not use motorcycle oils (low engine speeds) or for watercraft (other cooling systems) - their use does not provide the necessary lubrication of the piston group and parts of the entire engine! You can use, for example, oils from manufacturers Husqvarna, Stihl or Champion.
Petrol– any pure high-octane gasoline (with a number of 92 and higher, with a density in the range of 750-770 kg/m3). The purity of gasoline should be:
mechanical - to settle and store gasoline for work not in metal containers and for no longer than 1 (one) month, otherwise it will oxidize and lose its properties;
chemical – impurities and additives should not be present (they have different speed, degree and temperature of combustion). Old gasoline turns yellow or red, and the impurities have a strong smell of bitterness (for example, creosote) or acid (for example, methyl alcohol).

Fuel mixture proportion– 1:50 (2%) or 20 ml/cm3 of oil per 1 liter of gasoline. For example, in transparent plastic bottle(1 l) pour in half a measure of gasoline, then use a medical syringe (20 ml/cm3) to introduce two-stroke oil and mix, add gasoline and mix thoroughly. If the quality of gasoline is questionable or the working conditions are difficult, then the amount of oil can be increased to 22-25 ml/cm3. Shake the mixture before each filling! Store the resulting fuel for no more than two weeks! If the color of the mixture has changed (from the color sea ​​wave has become, for example, brown), then it is not recommended to use it!

Running in the brushcutter engine

Before starting work, it is necessary to break in the engine. It is necessary, on the one hand, to extend the service life of the gasoline engine, since during the break-in phase the moving parts must first get used to each other, on the other hand, during the break-in, you can acquire the necessary skills in working with a brush cutter.

1. Before the first 5 fuel tanks are used up, the proportion of the fuel mixture should be 4% (for 1 part of oil 25 parts of unleaded gasoline, or 40 cc of oil per 1 liter of gasoline), provided that high-quality synthetic oil for two-stroke engines;
2. Do not run the engine for long periods of time at maximum speed. Optimal - maximum torque speed;
3. Monitor the engine temperature, do not overheat and do not operate when it is not warm;
4. After break-in, change the oil.
5. Do not overload the engine (it should not operate at the maximum open throttle; during the break-in period, the maximum throttle opening should not exceed 2/3 of the entire stroke).

If the oil content in the fuel is high, there will be a slight accumulation of unburned oil in the muffler. This is normal, and when switching to the usual working proportion of the fuel mixture (2%), these residues quickly burn out.

Maintenance of brush cutters (trimmer)

Engine. The air filter must always be clean (no dirt or sawdust); The foam filter must be moistened with oil. The fuel filter must be checked once a week; in case of intensive use of the tool, replace it in time if necessary. Check the tightness of nuts and screws before starting work. Cleaning the muffler (or its mesh) and spark plugs from carbon deposits – as necessary.

Cutting discs. The cutting edges must be well and correctly sharpened using the necessary templates and files (emery), observing the angles of the cutting parts depending on the brand of the disc. Double-sided discs should be regularly turned 180° and worn evenly. A dull disc or a disc with poor or incorrect sharpening does not cut well, and thereby overloads the engine, which leads to an accelerated reduction in its service life.

Line and trimmer heads. Use only special cutting line – do not use wire or metal cables! Install fishing line only with the diameter recommended by the manufacturer. Wind the bobbin tightly, but do not cross the threads. Clean the mowing head from dirt and lubricate it if necessary. A worn or deformed head can damage the gearbox and/or shaft of the brush cutter.

Angular gearbox. If necessary, clean from dirt (such a “coat” does not allow the gearbox to cool properly) and apply Husqvarna grease, or a similar one, for the gearbox pair.

Protective covers. It is forbidden to work without a protective cover - this is dangerous for the life of the operator and others, and can also overload the motor of the brush cutter. For each type of cutting equipment, use only the protective guard provided by the manufacturer.

A gasoline trimmer is a fairly simple and effective device for cutting grass. By design, it occupies a middle position between manual device, since it is supported by weight, and wheeled, since it is driven by an engine. It is used mainly in dachas and suburban areas, so if there is a breakdown, get to a workshop or service center turns out to be not always possible.

Repairing a lawn mower yourself, if it does not involve replacing the entire assembly, is quite possible.

Device design

The essence of the device's operation is to transmit torque from a power drive - gasoline, electric or battery - to a cutting tool - a knife or fishing line. The transmission mechanism is a shaft located inside the rod. In devices with a curved shaft, its role is played by a steel cable.

The rod is attached to the drive gearbox - two- or four-stroke. When turned on, torque is transmitted through the shaft to the fishing line or knife.

The most complex part of the device is the motor. Damage to the shaft, belts, cutting tool are classified as mechanical breakdowns, but repairing the engine of a lawn mower usually causes difficulties. Some problems associated with contamination of engine components can be eliminated yourself. It is better to entrust replacement of spare parts or adjustments to a specialist.

Engine failure

The breakdown may not be associated with damage to the motor, but with the occurrence of obstacles in its operation. Before you begin disassembling, you should rule out simple breakdowns.

• Overheating – if failure occurs after 15 minutes continuous operation, then the reason is most likely simple overheating. However, an increase in temperature may be caused by grass and dirt clogging the starter grill or cooling fins. A video of repairing a lawn mower demonstrates a method for eliminating the failure - cleaning the grilles and replacing the filters. The photo shows the filter being replaced.

• Gasoline – it’s not just a matter of it being present in sufficient quantity, but it was also of sufficient quality. Trimmers are fueled with AI-92 and it is highly undesirable to use gasoline with a lower octane number. This leads to rapid clogging of the carburetor, its rusting, and much more serious breakdowns.
• The air filter is dirty - cleaning it is part of the standard trimmer care procedures. At the dacha, the filter is washed with gasoline and installed in place. In more suitable conditions, wash in water with detergents, dried and fixed back, after moistening it in the fuel mixture. In this case, repairing a Husqvarna or Shtil lawn mower is no different from troubleshooting a Chinese trimmer.

But if all of the above methods are used, then you will have to start disassembling the engine.

Replacing spark plugs

One of the most common causes of failure is contamination or damage to the spark plug - a crack in the housing. In the latter case, the spare part is simply changed.

1. The work is carried out with the engine turned off and cooled down.
2. The high voltage cable is disconnected.
3. The spark plug is unscrewed with a special wrench and inspected.
4. The presence of deposits on the spark plug indicates poor quality fuel. You can clean spare parts using white alcohol and brake fluid.
5. If the spark plug is faulty or damaged, it is replaced with a new one: inserted into place and tightened with a wrench.

In some cases, parts can only be used by the same model. But, for example, repairing a Shtil 130 lawn mower in 90% of cases allows you to replace new spare parts with old-style elements.

Starter breakdowns

The trimmer is started as follows: when the cord is pulled, the flywheel pawl engages with the teeth of the starter coil, and then, with a more vigorous tension, it starts the engine. If the launch is too sharp, the impact of the pawls leads to the destruction of the coil.

The second most common reason is a break in the flexible shaft when the coil gets jammed or when the grate becomes clogged with grass and dirt.

Do-it-yourself starter repair with a petrol mower eliminates the possibility. The module is sold as a finished unit and is simply replaced with a new one.

Lawn mower carburetor repair

1. First of all, the device is inspected from the outside for fuel leaks. Then the fuel hose is blown out, since often the cause of failure is its clogging.
2. If everything is in order, check the gasket between the engine and the carburetor and replace it if necessary.
3. A special device or a medical tonometer is used to check the tightness. If the pressure decreases, then the lawn mower requires carburetor repair.
4. As a rule, you can only disassemble and clean the device yourself. The module is cleaned with gasoline. The jet and channels are cleaned compressed air. If the blockage is very severe, use thin copper wire.

Setting up the device is a rather complicated procedure. If, after assembling and checking the carburetor, the trimmer starts, but immediately stalls, this is a sign of a failure in the settings.

Do-it-yourself repair of lawn mowers is shown in the video using the example of Husqvarna and Shtil machines.

An indispensable tool for a modern summer resident or owner of a private home is a lawn mower, which allows you to effectively and efficiently put the surrounding area in order. The period of active use of brush cutters is from late spring to October. Modern units are equipped with powerful and durable internal combustion engines, reinforced transmissions and main components. Despite this, physical deterioration, manufacturing defects or improper operation lead to failure of the trimmer. In order to repair a trimmer with your own hands, you must have at least basic knowledge in the field of technology and some experience in its repair.

The main component of any gasoline tool is the engine. internal combustion(ICE), which through in various ways transmits torque to the executive body. In a modern lawn mower, an alloy rod (pipe) is used as a transmission element between the motor and the trimmer head, inside which the drive shaft is located.

Petrol trimmer Husqvarna

Thanks to the high-speed engine, the rotation speed of the fishing line can reach 13 thousand revolutions per minute, depending on the manufacturer of the braid. In order to avoid mechanical and thermal damage to the gearbox, a special hole is provided in its housing for introducing lubricant in the form of ointments. To make it easier for the owner, the headset long work All models of brush cutters are equipped with a durable shoulder strap.

Cutting part of brush cutter

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

Trimmer cutting part

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

Made of durable polymer, during mowing it is subject to intense wear and, as a result, breakage. Therefore, from time to time it is necessary to check the presence of fishing line in the head and, if necessary, replace it. It is recommended to purchase an additional bobbin to quickly replace it with a reel that has run out of line.

Controlling a lawn mower

Types of lawn mower handles

Trimmers with internal combustion engines 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, on a U-handle braid, the throttle key and stop/start toggle switch are located on the right handle. In the D-shaped design of the handle, the gas adjustment key is located directly on the rod.

Trimmer malfunctions and how to fix them

Due to the presence of many components and parts, repairing a trimmer with your own hands involves eliminating breakdowns that prevent it from normal operation. The most basic malfunctions of gasoline scythes should be noted:

1. The trimmer engine does not gain speed;
2. Failure of the cylinder-piston group (CPG);
3. Ignition faults;
4. There is no connection between the internal combustion engine and the trimmer head;
5. Mechanical knocks during operation of the unit.
6. Repair of CPG lawn mowers

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

Trimmer problems

Lubrication of rubbing units in a lawn mower is carried out by adding a certain proportion of oil to gasoline. This process can be disrupted due to old oil falling out as sediment. In this situation, when starting the trimmer, the motor overheats greatly and in a matter of minutes the most expensive breakdown occurs. To resolve the problem you will need complete replacement CPG, namely: piston, oil seals, cylinder and piston rings. If you are not an internal combustion engine repair specialist and do not have experience working with technicians, then it is unlikely that you will be able to fix the engine without the help of a specialist. You can find out more about the stages of repairing a piston trimmer here.

Trimmer ignition troubleshooting

When the ignition of a lawn mower fails, the spark on the spark plug disappears and, as a result, the fuel mixture does not ignite.

Spit spark plug design

In this situation, it is quite important 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 diagnosis of the cross section, where the distance between the side and central electrodes should be 0.5-0.7 mm. In addition, it is necessary to pay attention to the steel sealing ring on the spark plug, loss of integrity or deformation of which can lead to etching of air from the combustion chamber and, as a result, a decrease in the power of the scythe.

Ignition flywheel with coil

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

Gasoline trimmer fuel system

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

Components fuel system trimmer

• due to a 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 of the mixture to enter the combustion chamber as a result of carburetor clogging.

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 (a small hole in the gas tank cap) with a thin needle or replace the fuel filter.

Carburetor repair

If fuel enters the carburetor, it must be cleaned or adjusted. Adjusting the trimmer carburetor involves restoring optimal mixing of the fuel mixture.

Carburetor trimmer with adjustment screws

To do this, pay attention to three adjusting screws: maximum speed (H), minimum speed (L) and idle speed (LA). To start setting, you need to completely tighten screws H and L and loosen 1 turn each. Then we start the scythe and let it warm up for 10 minutes to adjust the power system in operating mode. After warming up the internal combustion engine, press the gas button all the way (12,000 rpm). We restore the idle speed by unscrewing the LA screw. As soon as the trimmer head begins to rotate, you need to tighten the screw until it stops.

Gasoline scythe exhaust system

Trimmer Exhaust System

One of the frequent malfunctions of a lawn mower is the incorrect operation of the internal combustion engine, namely a drop in power when the speed increases (the mower stalls).

The reason for this work is that the exhaust system is clogged with particles of burnt oil. Manufacturers often make mufflers prefabricated and cleaning is quite simple. If the design of the spark arrester is non-removable, then it must be placed in water with detergents, and then dried with a regular or industrial hair dryer. Frequent clogging of the exhaust system indicates non-compliance with the proportions of oil and gasoline.

Repairing lawn mowers with your own hands: breakdowns and methods for eliminating them was last modified: June 25th, 2018 by Administrator