Do-it-yourself repair of lawn mowers - the main breakdowns are their elimination. Do-it-yourself grass trimmer repair, common causes of breakdowns Main breakdowns of a gasoline trimmer
How to work with a lawn mower (trimmer)
The principle of operation and the device motokos not much different from any other small gasoline garden equipment, for example, chainsaws, motor drill or motor shears. At the heart of the motokosa design is 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 individual manufacturer's recommendations specified in the product instruction manual. Always stick to the recommended proportion. The mowing set for motokosa is a mowing drum with a fishing line or a metal cutting knife, saw. The transmission of engine speed to the mowing set 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.
For achievement good results mowing, as well as long-term operation of equipment, it is important to properly operate and care for the lawn mower. Even if you are holding a lawn mower in your hands for the first time, correct technique mowing you will master quickly. The device is simply rotated 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 the best results in mowing quality.
The basic mowing technique is the most commonly used.
Because cutting tool rotates counterclockwise, then working practice the most common mowing movement is from right to left. The advantage of this method is that the cut grass falls on the already mowed surface.
large, flat surfaces- the correct approach.
Large flat surfaces are best for you to mow with the square method. The area is distributed in squares, then you always work along outer side to the center.
Basic technique in case of tall grass.
With very tall grass or tough weeds, it is recommended to mow in both directions of travel: first, you cut the upper part of the grass being cut to the right in one motion, and the lower part in the opposite direction (to the left). Mowed grass and in this case remains to lie on the left.
Along the slope - mowing after mowing.
You'll make good progress with straight cuts, especially on slopes: cut one cut parallel to the slope and then come back down the swath. Then mow the next higher mowing. And here, the cut grass is always laid on the already cut surface.
Masterfully bypass obstacles - mow effortlessly.
To cut close to trees or shrubs without damaging branches or trunks, a cutting line is best. If many plants are located at a small distance from each other, mowing is suggested here before mowing. To do this, use the protection of your brushcutter as a guide. Lead it all the time directly along the trunk of a tree or shrub, and move around them. The trunk will remain protected, the area around the trunk will be mowed.
A haircut. Hold the trimmer head directly above the ground at an angle. The work is done by the end of the string. Let the string run at its own speed. Do not press the line against the area to be mowed! This overloads the motor and the mowing head - they can fail or melt!
Cutting. The trimmer is ideal for cutting grass that is difficult to reach with a regular lawn mower. Keep the string parallel to the ground while cutting. Avoid pressing the trimmer head to the ground as this can ruin the lawn and damage the tool.
Cutting 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 it will be returnable. The blade should cut the grass with its left edge (on the clock face between 8 and 12).
How to prepare the fuel mixture correctly: Fuel \u003d 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 water equipment (other cooling system) - 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 above, with a density in the range of 750-770 kg / m3). The purity of gasoline must be:
mechanical - to defend and store gasoline for work not in metal containers and not longer than 1 (one) month, otherwise it oxidizes and loses its properties;
chemical - impurities and additives should not be present (they have different speed, degree and temperature of combustion). Old gasoline turns yellow or reddish, and impurities have strong odors of bitterness (such as creosote) or acid (such as methanol).
Fuel mixture ratio- 1:50 (2%) or 20 ml / cm3 of oil per 1 liter of gasoline. For example, in a transparent plastic bottle(1 l) pour in half a measure of gasoline, then medical syringe(20 ml/cm3) add two-stroke oil and mix, top up with gasoline and mix thoroughly. If the quality of gasoline is doubtful 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 received fuel no more than two weeks! If the color of the mixture has changed (from the color sea wave became, for example, brown), then it is not recommended to use it!
Engine run-in
Before starting work, it is necessary to break in the engine. It is necessary, on the one hand, to extend the service gasoline engine, since during the running-in phase, the moving parts must first run in to each other, on the other hand, during the running-in, you can acquire the necessary skills to work with a brushcutter.
1. Before the first 5 fuel tanks are used up, the fuel mixture ratio should be 4% (to 1 part of oil 25 parts of unleaded gasoline, or 40 cc of oil to 1 liter of gasoline), provided that high-quality synthetic oil for two-stroke engines is used;
2. Do not run the engine for a long time at maximum speed. Optimal - revolutions of maximum torque;
3. Monitor the temperature of the engine, do not overheat and do not work on cold;
4. After running in, change the oil.
5. Do not overload the engine (it should not operate at maximum throttle, during the break-in period, the maximum throttle opening should not exceed 2/3 of the entire stroke).
With an increased oil content in the fuel, there will be a slight accumulation of unburned oil in the muffler. This is normal, and when switching to the normal operating proportion of the fuel mixture (2%), these residues quickly burn out.
Servicing motokosa (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, if necessary, replace it in time. Check the tightening of nuts and screws - before starting work. Cleaning the muffler (or its mesh) and spark plugs from carbon deposits - if 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. Turn double-sided discs regularly by 180° and wear 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 motor resource.
Line and trimmer heads. Use only special mowing line - do not use wire or metal cables! Install only the diameter recommended by the manufacturer. Wind the bobbin tightly, but do not cross the turns. Clean the mowing head from dirt and lubricate if necessary. A worn or deformed head can damage the gearbox and/or brushcutter shaft.
Angle gearbox. Clean off dirt as needed (such a "coat" does not allow the gearbox to cool properly) and apply Husqvarna grease, or similar, to the gearbox pair.
Protective covers. It is forbidden to work without a protective cover - it is dangerous for the life of the operator and others, and can also overload the brushcutter engine. For each type of cutting equipment, use only its own protective cover provided by the manufacturer.
The trimmer, both electric and with an internal combustion engine (ICE), is an indispensable tool in the summer and autumn period for owners of cottages and private houses. With its help, weeds, small shrubs are easily removed and the lawn is trimmed. But, like any technique, trimmers fail at the most inopportune moment. To fix malfunctions with your own hands, the user of this technique first needs to determine the cause of their occurrence.
With a lawn mower and an electric trimmer, if you do not consider the breakdowns associated with the bar and the mowing head, malfunctions mainly occur in the area of the engine.
Breakdowns of petrol trimmers
Typical breakdowns of a gasoline trimmer that owners of this unit most often encounter are as follows:
- engine breakdown;
- problems with the carburetor;
- fuel supply problems;
- muffler malfunction;
- gearbox failure;
- the starter is broken;
- air filter problems
- clogged breather on gas tank.
Malfunctions of electric trimmers
Since the device of an electric mower is much simpler than a motor-trimmer, there are few reasons for its failure.
It should be noted that the elimination of some of them is best left to a specialist.
Basically, the trimmer stops working normally in the following cases:
- electrical cable failure;
- the control button is faulty;
- burnt motor stator winding;
- breakage of contact connections on the engine.
Why does the gas trimmer not start?
The reasons why the gas trimmer stopped starting can be different, so a step-by-step diagnostics of the device is required.
Fuel tank (fuel quality)
Remember that it is always necessary to start the machine before checking the availability and quality of fuel. IN this case do not be greedy and save, as well as “be clever” about the amount of oil added. Everything must be done according to the manual attached to the device, since if the piston group fails, its replacement will cost about 70% of the total cost of the trimmer. Pour fuel in such a way that you will completely use it when performing work. . Gasoline remaining in the tank loses its properties after a while and can harm the engine. Therefore, do not prepare the mixture for the future and in large quantities. If the lawn mower does not start well, try draining the “old” fuel from the tank and filling it with a freshly prepared mixture.
Important! Filling the device with fuel, the origin of which is unknown, is fraught with negative consequences. Gasoline must be of high quality, bought at a gas station, and its brand must be at least AI-95.
Candle and candle channel
So, you changed the fuel, but nothing has changed, and the trimmer still won't start. In this case, it is worth checking the candle channel: does it throw a combustible mixture. Often users translate air damper to the “OFF” position when starting, and when the engine is started, do not turn it to the “ON” position, after which it stalls. Further, an attempt to start the internal combustion engine again leads to the fact that the candle is flooded with gasoline, and the start becomes impossible. To diagnose and fix possible problem in this node, do the following.
- It is necessary to unscrew the spark plug, wipe it well and dry it. When installing a candle in an internal combustion engine cylinder, it must be dry.
- Drain any accumulated fuel from the combustion chamber. This is done through the hole from which you unscrewed the candle.
- If there is carbon deposits on the electrodes of the candle, it must be removed either with a thin file or with a nail file.
- Do not forget to set the gap between its electrodes before installing the part in place. The gap on the candle should be 1 mm. You can use a coin as a feeler gauge to check the clearance.
- Next, assemble the block, read the start instructions and try to start the engine again.
If the internal combustion engine does not start, then you will need to check the spark. For this:
- unscrew the candle;
- put on it a cap of a high-voltage wire;
- touch the metal part of it to the cylinder body (to ensure contact, you can insert a tubular wrench) as shown in the figure below;
- pull the starter cord so that several revolutions of the engine occur.
Normally, with each pumping of the piston, a spark should jump between the electrodes of the spark plug. If there is a spark, then the reason that the internal combustion engine does not start must be sought in other nodes of the apparatus.
For a better understanding of the process, how to test a candle for a spark, you can use this video, where the test is shown using the Soyuz lawn mower as an example.
If there is no spark, then at the beginning check the cable connecting the candle to the coil - perhaps the reason is precisely in it. You can call it with a tester. If an open circuit is detected, the high-voltage wire will need to be replaced.
Also, the reason that the spark has disappeared can be ignition coil failure(magneto). The figure below shows what a coil (magneto) looks like from a Patriot gasoline trimmer (Patriot).
To rule out a malfunction, you will need to check the trimmer magneto with a tester, namely, its primary and secondary windings. On the primary winding, the resistance should be in the range from 0.4 to 2.0 ohms. If the device shows 0, this means that a short circuit has occurred in the winding, and if infinity is a clear sign of an open circuit. The resistance on the secondary winding should be in the range of 6 to 8 kOhm.
On some coils, it can reach a value of 15 kOhm.
If your lawn mower does not start well or stalls immediately after starting, you should pay attention to the air filter, as it may be clogged, as a result of which air does not enter the combustion chamber and the fuel does not ignite. To check if the filter is the problem, remove it and try to start the engine. If it works, then the reason is found. The filter needs to be replaced or rinsed well and dried before installation. In case you found air filter oil, it must be washed with gasoline, squeezed well and dried for at least 2 hours before being replaced.
If, with the air filter removed, the unit still does not start, it is recommended to check the fuel filter.
Fuel filter
This filter cleans the fuel from possible contaminants. If it is clogged, then gasoline does not enter the cylinder, and, accordingly, the unit does not work or stalls after starting. The fuel filter is located at the end of the intake hose that is inside the fuel tank. To get to the filter, it is necessary to remove the plug with the tubes coming out of it.
When removing the plug, the intake hose may detach and remain in the tank. It is removed with tweezers.
Next, remove the old fuel filter from the hose and put a new, pre-purchased one on it. You can also clean the fuel filter if you don't have a new one. The filter must be secured to the hose with a spring clip.
Install the intake tube on the plug and insert the latter into the tank.
It should be noted that in some models of trimmers, the intake hose is not located on the cork, but inside the tank. You can remove it with tweezers or a hook bent from a wire.
The breather is check valve, which is designed to equalize the pressure in the gas tank. If it is clogged and does not let air into the side of the tank, then a vacuum forms inside the fuel tank, and fuel stops flowing into the carburetor. To check the valve is working, remove the hose that goes from the reservoir to the carburetor. If gasoline does not flow out of the tank, then the breather is clogged.
Trimmer users often wonder: where is the breather? This valve is usually in the gas cap and looks like the following figure.
Cleaning the breather is very simple: disassemble the valve and flush all of its components. In some lawn mowers, this valve may be located directly on the fuel tank. You won’t be able to find it right away, because it is hidden from view under the starter housing. Such a breather is cleaned with a regular needle.
The reason that the trimmer has significantly lost power, and when you try to increase the engine speed, it picks them up slowly, is often a clogged exhaust channel through which exhaust gases exit the combustion chamber.
It is necessary to remove the muffler so that no fumes get inside the cylinder. Next, clean the exhaust channel from carbon deposits.
This must be done very carefully, preventing soot from entering the combustion chamber.
After this procedure, the weak power of the unit and the slow increase in the speed of rotation of the mowing head will no longer upset you.
Insufficient compression
If the compression is insufficient, then starting the engine, in most cases, will not work. To check compression, you can use a car compressor.
What compression should be? Normally, compression should be not less than 8 kg / cm 2. Although even at 8 kg / cm 2, some engines do not idle and stall, since the fuel is not pumped up sufficiently. If your lawn mower does not pump above 8 kg / cm 2, then you will have to check the cylinder, piston and rings.
Also, poor compression may be due to loose carburetor. Check if it's wobbly. If so, tighten the fasteners holding it well. Also, if the carburetor is not screwed on well, you may notice that gasoline drips during operation.
Electric trimmer vibrates
Many mower users have noticed that after some time after the start of the machine, it starts to vibrate strongly. On some trimmers, mainly in more expensive models, an anti-vibration system is installed in the form of shock absorbers located between the engine and the bar. But in some cases, even she does not save from strong vibration. The reason that a strong vibration appears in the trimmer may be a small amount or complete lack of lubrication on the hard or flexible shaft located inside the bar of the device.
Replacement rigid shaft lubrication happens like this:
- unscrew the gearbox located at the bottom of the rod;
- after removing the gearbox, you will see the end of the shaft, which you need to pull to remove the part;
- after removing the shaft, it must be liberally lubricated with a special grease "Shrus-4" or ordinary - "Litol-24";
- apply a small amount of grease to the shaft and spread it evenly along the entire length of the part, including the splines at the ends of the rod (if they work out, the shaft will have to be replaced);
- after lubrication, insert the shaft back into the shaft and put the gearbox in its original place.
Flexible shaft lubrication is done as follows:
- unscrew and remove the mowing head;
- remove the rod from the electric motor by unscrewing a couple of bolts;
- pull the flexible cable out of the rod;
- lubricate the cable with grease along the entire length.
This is done as follows: first you need to lubricate the end of the cable, and then insert it into the rod, after which, as it moves inside the pipe, you should apply lubricant to the part and evenly distribute it over the surface. Then insert the flexible shaft rod into Electrical engine and secure it.
In the case when the lubrication did not help, and the vibration continues to appear, it will be necessary to change the flexible shaft.
The trimmer gets very hot
Overheating of the trimmer can occur for many reasons:
- gasoline does not have the octane number indicated in the instructions for the unit;
- the proportions of gasoline and oil are not observed during the preparation of the fuel mixture;
- the mixture of fuel and oil was prepared long ago (the mixture cannot be stored for more than 2 weeks);
- the trimmer works over the time set according to the instructions;
- a low-power trimmer is used on thick and hard grass, the device works with overload and heats up quickly;
- has shifted towards the bar or the cassette cover has stuck.
The latter happens if you set mowing head not suitable for this machine, or when the axle moves inside the boom. These changes make it difficult to rotate, the load on the engine increases, and it overheats.
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One of the main garden tools in the garden or in the country house is a lawn mower or trimmer. Gardeners use this tool for mowing grass, weed control, mowing the lawn. Like any other tool, the trimmer requires careful maintenance and is required. Maintenance do-it-yourself gas mowers.
Structural design
The trimmer consists of three parts: a gasoline engine, a rod with a shaft inside and a cutting element. Torque is transmitted through the shaft from the motor to the cutting head. In trimmers with a curved bar, the role of the shaft is performed by a cable. The rod itself is attached to the gearbox of the gasoline engine. There is a motor control on the bar, a belt can also be attached for convenient use of the trimmer. The cutting element in gas mowers uses a fishing line wound around a trimmer head or special knife used for cutting large weeds.
The main and most complex unit in the trimmer is the engine. In household and semi-professional lawn mowers, two types of engines are used - 2-stroke or 4-stroke. Depending on the type of gasoline engine, its refueling and maintenance are different.
- 2-stroke engines do not have their own lubrication system, so they do not run on pure gasoline, but on a mixture of gasoline and oil. The latter, getting into the ignition chamber, lubricates the moving components of the engine.
- 4-stroke engines are lubricated by oil in the crankcase. They run on pure gasoline without impurities.
Do-it-yourself lawn mower repair and trimmer maintenance can be carried out without outside help. If you need to replace motor parts or tune it, then you need to contact the repair shop.
First run at the beginning of the season
In late spring, when the active use of gas mowers begins, before starting work, it is necessary to inspect and check the performance of your tool. Be sure to lubricate the rotating parts, inspect and, if necessary, replace the cutting elements (knife or fishing line). Check for fuel mixture in the tank. If you drained fuel at the end of the previous season, be sure to pump fuel into the engine using suction (if the engine has one).
If you are using the trimmer for the first time, be sure to read the instruction manual. Such instructions should be attached to each lawn mower.
Starting most two-stroke engines is pretty straightforward. Use the procedure described in your trimmer's instructions if it differs from the following:
- Move the choke lever to the open position. Place the trimmer on its side so that the air filter is on top.
- Hold or lock the throttle in the on position (the throttle should be held until the engine is warm).
- If the device has an on/off switch, move it to the on position (usually labeled "I", not "O").
- Make sharp, quick jerks with the starter handle until you hear the engine try to start. This should happen between 1-6 pulls, but no more.
- Close the throttle valve halfway and resume starting the starter. The engine should start after 2-6 additional pulls. If not, move the throttle lever to the full position and pull the starter handle again. Return the lever to half throttle and pull 3 more times.
- After starting the engine, keep pressing the start button and allow it to warm up for 10 seconds, then disable the starting system.
- When the brushcutter warms up, it should restart with the throttle in the closed position.
You can also use another proven technique. If you remove the air filter before starting and pour a couple of drops of the mixture into the carburetor and assemble it again, then the engine should start.
How to repair a lawn mower if the engine does not start.
Before you repair the lawn mowers with your own hands, you first need to identify the malfunction. First you need to check the filters - both fuel and air. The air filter, if necessary, can be washed in gasoline or with water and detergents.
Air filter After the filter is well wrung out and dried. Before installing on the air filter, it is advisable to moisten a couple of drops of oil for 2-stroke engines.
The fuel filter is not washed, only replaced.
Note. It is forbidden to leave the inlet branch pipe of the fuel line without a filter.
Checking the glow plug.
On a cold engine, remove the high-voltage wire from the spark plug and unscrew it with a special key. This key is provided by the manufacturer so that you can easily repair the lawn mower with your own hands.
photo of glow plug removal First, visually inspect it for contamination, also check if it is filled with a fuel mixture. If the candle is dirty, it must be cleaned with a needle file or an iron brush. If the candle is flooded, it must be dried, and the remaining fuel must be drained from the combustion chamber through the candle hole. Be sure to check the gap at the spark plug - it should be no more than 0.6 mm.
Crack in spark plug insulation If cracks are visible on the ceramic part of the candle, be sure to change the candle.
Check for spark.
Insert the high voltage wire into the removed spark plug and press the metal part of the spark plug against the engine body. It might be difficult to do this because plastic cover usually closes the engine, and the spark plugs are hard to get access to the metal case. You can use a bolt or something else to make contact between the spark plug and the housing. Turn the trimmer on and pull the starter cord. This can be difficult to do on your own, so find a trusted helper to help you get your brushcutter repair done!
Spark test The spark should be blue. If it's hard to see a spark in the bright sunshine- move the trimmer to the shade or indoors. If there is no spark, try changing the spark plug or high voltage wire. If this does not help, you need to contact the repair shop.
What to do if the trimmer starts up and stalls.
Check the fuel tank air valve. If the valve is clogged, a vacuum is created in the tank and the carburetor receives less fuel. The trimmer will start, but then stall. Clean the valve. You can also start a lawn mower with an incompletely screwed tank cap. Check the fuel and air filter.
A lawn mower can also run unevenly or stall due to a poorly adjusted carburetor. How do you know it's a carburetor? - uneven operation of the engine or vibration during its operation. There may be a couple of problems here:
- Poor idle speed control
- Changed composition of the fuel mixture
- Carburetor adjusting bolts loosened due to vibration
Carburetor adjustment must be carried out with clean fuel and air filters and be sure to follow the instructions that come with the trimmer.
An engine is properly tuned when:
- A cold engine idles evenly.
- A hot engine revs slowly without load.
- The engine runs evenly in any position.
Be sure to check the fuel line for cracks, leaks, physical damage. If any are found, the fuel hose must be replaced immediately.
Silencer mesh cleaning
The exhaust muffler is equipped with a mesh - anti-spark screen. Over time, this mesh becomes clogged, growing soot from burnt oil and reducing engine power output. This problem is solved by cleaning the mesh with an old toothbrush, compressed air, or a small wire brush.
Screen cleaning As you can see, repairing a lawn mower with your own hands is not such a difficult task and many will be able to fix most of the malfunctions.
Additional questions about servicing lawn mowers
Can I leave the fuel stored in the brushcutter?
No, fuel must not be stored in the block. If the trimmer will not work for more than 30 days, drain the fuel and start the lawn mower and let it run until the engine stops.
What kind of gasoline should be used?
Most lawn mowers run on 92-octane gasoline. Never use gasoline with a lower octane rating or diesel fuel. Try to use freshly purchased gasoline and mix it with recommended 2-stroke oil.
What is the correct spark plug gap?
The spark plug gap on all engines is 0.5 - 0.6 mm.
An indispensable tool for a modern summer resident or owner of a private house is a lawn mower, which allows you to effectively and efficiently put the surrounding area in order. The period of active use of lawn mowers falls on late spring until October. Modern units are equipped with powerful and durable internal combustion engines, reinforced transmission and main components. Despite this, physical wear, manufacturing defects or improper operation lead to the failure of the trimmer. In order to repair the trimmer with your own hands, you must have at least basic knowledge in the field of technology and a little experience in its repair.
The main unit of any gasoline tool is an internal combustion engine (ICE), which, through various ways transfers torque to the actuator. In a modern lawn mower, an dural rod (pipe) is used as a transmission element between the motor and the trimmer head, inside which the drive shaft is located.
Husqvarna petrol trimmer
Thanks to the high-speed motor, the line speed can reach 13,000 rpm, depending on the braid manufacturer. In order to exclude mechanical and thermal damage to the gearbox, a special hole is provided in its body for introducing lubricant in the form of ointments. As a headset that makes it easier for the owner during long-term work, all models of lawn mowers are equipped with a strong shoulder strap.
The cutting part of the scythe
Regardless of the manufacturer, almost every model comes with fishing line and steel knives.
The cutting part of the trimmer
The cross section of PVC trimmer line can vary from 1.5 to 3.0 mm.
Made of durable polymer, it is subjected to intense wear and tear during mowing. 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 spool to quickly replace it with a spool with no line.
Brushcutter management
Types of lawn mower handles
The ICE trimmers on the market today are equipped with a D-shaped, U-shaped or T-shaped handle, where the main controls of the unit are located. For example, in a U-handle scythe, the throttle key and stop/start toggle switch are located on the right handle. In the D-shaped version of the handle, the gas adjustment key is located directly on the bar.
Trimmer malfunctions and solutions
Due to the presence of many components and parts, do-it-yourself trimmer repair involves eliminating breakdowns that prevent it normal operation. It should be noted the most basic malfunctions of gasoline braids:
- The trimmer motor does not gain momentum;
- Breakage of the cylinder-piston group (CPG);
- Ignition faults;
- There is no connection between the internal combustion engine and the trimmer head;
- Mechanical knocks during operation of the unit.
- Repair of CPG lawn mowers
The main unit of any internal combustion engine is the cylinder-piston group (CPG), which can fail due to wear of parts or poor quality of the fuel mixture.
Trimmer problems
The lubrication of rubbing units in the lawn mower is carried out by adding a certain proportion of oil to gasoline. This process can be disturbed due to old oil precipitating out. In this situation, when starting the trimmer, the motor overheats greatly and the most expensive breakdown occurs in a matter of minutes. To troubleshoot a problem, you will need complete replacement CPG, namely: piston, seals, cylinder and piston rings. If you are not an internal combustion engine repair master 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. Detailed information about the stages of repair of a piston trimmer can be found here.
Troubleshooting Trimmer Ignition
When the ignition of the lawn mower fails, the spark on the candle disappears and, as a result, the fuel mixture does not ignite.
Spit spark plug design
It is important enough in this situation not to rush to replace the coil, since the cause of the breakdown may be the lack of contact in the switch on the control knob.
An important point when troubleshooting the ignition of the trimmer will be the diagnosis of the cut, 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 candle, the 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 braid.
Ignition flywheel with coil
If the replacement check of the electrical circuit, the candle and its contacts did 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 gap value, you will need to loosen the coil mounting bolts and set the trimmer ignition with a special measuring probe.
Fuel system of a petrol trimmer
A clear sign of a malfunction in the engine power system is the absence of traces of the fuel mixture on the spark plug electrodes, which may be due to the following defects:
Components of the trimmer fuel system
- due to a clogged hole in the gas tank, a vacuum is created that 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;
- not entering the mixture into the combustion chamber as a result of clogging of the carburetor.
You can quickly determine the cause of the malfunction by dismantling the fuel hose leading to the carburetor. If 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, then it is necessary to clean or adjust it. Adjusting the trimmer carburetor involves restoring the optimum mixing of the fuel mixture.
Trimmer carburetor with adjustment screws
To do this, pay attention to the three adjusting screws: maximum speed (H), minimum (L) and idle speed (LA). To start the adjustment, it is necessary to fully tighten the screws H and L and loosen them by 1 turn each. After we start the braid 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 supply button all the way (12,000 rpm). We restore the idle mode by unscrewing the screw LA. As soon as the trimmer head begins to rotate, it is necessary to tighten the screw until it stops.
Gasoline exhaust system
Trimmer exhaust system
One of frequent malfunctions lawn mowers is the incorrect operation of the internal combustion engine, namely, a drop in power with an increase in speed (the scythe stalls).
The reason for this work is the clogging of the exhaust system with particles of burnt oil. Often, manufacturers make mufflers prefabricated and cleaning is quite simple. If the design of the spark arrester is non-separable, then it must be placed in water with detergents, and then dry with a conventional or industrial hair dryer. Frequent clogging of the exhaust system indicates non-compliance with the proportions of oil and gasoline.
Do-it-yourself lawn mower repair: breakdowns and methods for their elimination was last modified: June 25th, 2018 by Administrator
