Design
The mower is quite simple. The main part of the unit is a two-stroke or four-stroke internal combustion engine. It is connected to the shaft using a gearbox. It directs the energy of movement to the operating link.
The hollow rack conceals the cable that connects them. In close proximity to the engine there is a starter, air filter and carburetor.
Operating principle
The grass is cut using a knife or fishing line located on the brush cutter. The rotation speed of the cutting element can reach 13 thousand rpm.
If you install a fishing line on the base of the unit, its diameter should be within 1.5-3 mm. The string has one main drawback: it wears out quickly.The line is suitable for cutting small vegetation, but for rough bushes and overgrown areas it is better to use metal knives. They are distinguished by a variety of types.
The cutting discs and gearbox are protected by a special casing to protect the user from small particles that fly off the knives at high speed.
There are holes on the casing intended for supplying lubricant. To make it easier to work with the tool, it has a special belt.
The center of control for the scythe is located on a handle attached to the boom. The handle can be T-shaped or U-shaped. Fuel is poured into a special tank. For two-stroke engines, oil is mixed with gasoline.
Malfunctions of a new lawn mower
List of malfunctions of a new lawn mower (gasoline trimmer), which also applies to used tools with a two-stroke engine:
| Malfunction | Possible reason |
| Engine won't start |
|
| Formation of carbon deposits on a spark plug |
|
| Increased fuel consumption | Carburetor adjustment required. |
| Increased vibration of the rod | Unbalance of the knife or spool of fishing line. Inspect the knife (spool) for damage or manufacturing defects. Check that the reel feeds line evenly in both directions. |
| Releasing the line every time you touch the ground | Weak spring in the line spool. Stretch the spring - this can be done manually. How much to stretch the spring is determined experimentally. |
| The control knob falls off (grip) | If the plastic control handle (bike handle, grip) falls off the metal handle, cut one fingertip from a thin rubber glove, put it on the outermost part of the metal handle, then install the bicycle handle (grip). |
| The handle rotates at the attachment point | If the metal handle (3D adjustable handle) rotates where it attaches to the barbell, wrap a piece of rubber glove around the handle where it attaches. |
An example of securing the composite handle of a Khoper lawn mower with anti-rotation protection using parts of a rubber glove:
Most common breakdowns
Knowing how the unit works, it will not be difficult to troubleshoot problems on your own.
The most common breakdowns:
- Engine damage. If the unit refuses to start or creates unusual vibration.
- Fuel filter clogged. If the unit turns off at minimum speed, or if fuel does not enter the combustion chamber.
- No spark. Most likely fuel flooded the spark plug.
- Noticeable vibration of the rod, making it difficult to operate the lawn mower.
- Overheating of the gearbox in a short period of time.
- Reducing the speed of rotation of the knives at minimum rotations.
- The starter grid is clogged. Also, the starter in a lawn mower can break a too abrupt start.
- Carburetor clogged. Carburetor problems can often be solved by replacing poor quality fuel with better quality fuel. Also, if the unit is not configured correctly, the scythe may stall when turned off.
Structural elements of chainsaws
All chainsaws are similar in structure, regardless of whether they are made in Europe (ECHO, Stihl, Husqvarna) or at home (Cedar, Urals). The main elements are located inside the body. fuel tank and engine, and outside. starter, handle, part of the saw (bar) with chain. A sharp tug of the cable starts the motor and it is the saw blade.
READ Starting the Stihl 180 Chainsaw After Downtime
To begin with, we suggest you familiarize yourself with video clips that show how a chainsaw works and how it works:
From time to time, saws develop malfunctions that require disassembly. What can happen to such a simple mechanism as a chainsaw? At least the following:
- Stops starting;
- It starts but soon stops;
- It ceases to function in context;
- Loses strength;
Most problems are related to engine failures (fuel system, exhaust system, ignition, piston part of the cylinder) or failures of other systems and components (clutch, chain brake, tire, lubrication system). Let's look at the most common faults and how to fix them.
The working chainsaw starts with one jerk and does not cut
Troubleshooting Methods
For quality maintenance of equipment, please pay attention to the repair instructions.
Fuel system
You need to start repairing the trimmer with a step-by-step study of the main components. It is necessary to look at the fuel in the tank and the presence of lubricant on the metal parts of the unit.
The quality and quantity of gasoline and oil plays an important role in the operation of the tool. If fuel is used improperly, the piston system may fail.
Cycle No. 1: what mistakes of beginners lead to breakdown of the trimmer motor and prevent its normal operation
At this stage the person:
- prepares the working mixture, pours it into the tank;
- installs the trimmer stably;
- moves the controls to the starting position;
- works as a starter.
6 common mistakes when working with fuel
The manufacturer clearly indicates in the instructions the brand of gasoline with octane number, oil and their proportions.
The first three errors are that the user of the brush cutter violates all or one of these requirements. The engine will most likely start and work, but its service life may decrease sharply.
A small amount of oil, as well as its absence, will lead to the cylinder walls not being properly lubricated, and the piston rings will scratch them instead of sliding.
Excess oil will simply burn out, forming soot. It will contaminate everything, including the piston and cylinder.
Carbon deposits get into the valves, blocking their operation, after which the engine will no longer start.
You will have to disassemble and clean the carburetor, or even install a new one. Of course, you can try to wash the piston and cylinder: you may be able to get them into working condition, but it’s better not to let this happen.
The fuel mixture must be prepared with high quality and in strict proportions. Repairing a damaged engine is expensive, about 70% of the price of a new gasoline trimmer.
To prepare a high-quality fuel mixture, my trimmer kit comes with a special container with factory-calibrated divisions. Gasoline is carefully poured into it to the level of 500 ml, and then oil to the required mark.
An alternative method is to prepare a fuel mixture by pouring gasoline into a calibrated container, for example, a liter canister or plastic bottle to the mark, and adding oil with a medical syringe according to its divisions.
Dosing with a syringe is more convenient and is considered the most popular method.
I recommend pouring gasoline through a funnel with a narrow neck that has a filter: a metal mesh - protection against the ingress of small debris.
The prepared mixture should be shaken well and mixed until a uniform color appears. Only after this can it be poured into the tank.
If the mixture is not stirred, it will remain in the tank, and through the carburetor it will enter the combustion chamber in portions with different ratios of gasoline and oil.
Fractions of oil clots clog the candle. The engine stops, stalls, and does not start. This is the fourth mistake made by beginners.
Please note that gasoline is flammable. There is a risk of fire. Therefore, it is necessary to pour the mixture at a safe distance from buildings, and in the event of a spill, which often happens, to eliminate the causes of a possible fire. Violation of fire safety measures - mistake No. 5.
After pouring fuel into the gas tank, the latter is closed with a screw cap and the absence of leaks is checked. The trimmer is raised up so that the gasoline fills the plug. There should be no leaks either from under the cap or from the fuel hoses.
The absence of such a check is mistake No. 6. It may cause a fire.
There is one technical trick here that may cause the gas trimmer engine to not start due to a cutoff in fuel supply. If you look closely at the center of the plug, you can clearly see the round hole.
We turned the lawn mower over. Gasoline has filled the plug, but does not flow out through the hole: there is a breather inside. He's fine.
From the inside, its design is clearly visible: a built-in valve system made of plastic and rubber.
In the normal state, the valve is pressed against the hole and fuel does not flow out. When the gasoline engine is running, the fuel mixture is consumed through the carburetor. A vacuum is created in the tank. The vacuum opens the breather valve and pressure is restored.
You should be aware of two consequences of a malfunctioning breather:
- A constantly open hole means fuel pours out of the tank when it is tilted (excessive consumption and the risk of fire).
- Contamination or sticking of the valve channel is the reason why the lawn mower does not start normally or stalls.
Candles
Next is to inspect the spark plugs. It is important to determine the presence of a spark when interacting with the frame of the unit. The ignition of the lawn mower is due to working spark plugs. If defects are found, immediately remove the voltage cable from the spark plug.
If the spark plug is dirty, has holes or breaks, it must be replaced with another one. The channel should be dried. The distance between the electrodes should be 0.6 mm.
Using a special key, a new spark plug is installed, then you need to connect the voltage wire.
Quick start of the unit
- We place the tool on its side so that the air filter is on top. In this arrangement, it is possible to ensure that the fuel mixture reaches the very bottom of the carburetor. The engine can start on the first try if you remove the air filter before starting and pour a small amount of the mixture into the carburetor (a few drops are enough, and don’t get too carried away), and then install the recently removed parts back. This method has been tested in practice and works in most cases. Surely many owners of an old domestic car used a similar method on their car. The principle with the scythe remains absolutely the same.
- If the first advice does not bear fruit, then you need to unscrew the spark plugs and look at them carefully. We unscrew the spark plug, check its functionality, and then dry the combustion chamber. A candle that shows no signs of life must be thrown out and a new one installed. If everything is in order with the old one, then we put it in place and move on to the next method.
- If the spark plug is fully operational, the filter is clean, and the fuel mixture is fresh, then you need to resort to a universal method of starting the lawn mower. It is worth closing the carburetor choke and pulling the starter handle once. Then open the damper and pull the starter about 3 more times. This procedure is repeated 3 to 5 times. The engine should start. But you shouldn’t pull the handle too hard, because in this case you will also have to repair the starter of the lawn mower. This will only be needed if the cable breaks or the handle breaks. In other cases, it is recommended to replace the starter immediately. This unit is sold completely assembled.
- There is also a very simple way to get a braid. Many people forget to press the gas choke after filling the fuel mixture. It is usually located near the gas tank. On a household mower, it looks like an ordinary ball of air, which must be pressed 5-10 times for the mixture from the tank to go as intended. In most cases, this option works flawlessly. You just need to help the fuel flow through the channel.
Correct replacement of spark plugs
Many people know that spark plugs should be changed periodically, but few do it correctly and in a certain sequence. To perform all the manipulations correctly, you should familiarize yourself with the correct procedure.
Stop the engine and wait until it is cold, otherwise you may be seriously burned.- Disconnect the high-voltage wire from the spark plug. We unscrew the spark plug using a special wrench. We examine the candle.
- The part must be replaced if it is in poor condition, very dirty, or if a crack is found on the body.
- Check the gap between the electrodes. Their size should be 0.6 mm.
- We install a new spark plug and tighten it with a wrench.
- We install a high-voltage wire on the central electrode of the spark plug.
There is nothing complicated in this procedure , and absolutely any owner of a gasoline scythe can cope with it.
The lawn mower stalls after starting
The engine may stall after starting the device if the carburetor is not configured correctly or is misadjusted. It's very easy to identify. Vibrations may occur and are clearly felt during operation. You can make the adjustment yourself; you should strictly follow all the instructions written in the manual.
The engine may also stall due to a clogged fuel valve . In this case, it must be cleaned, and then the problem will be eliminated.
If the scythe starts up and then suddenly stalls, this means that the supply of fuel to the carburetor is difficult. It is necessary to loosen the carburetor valves , then the free flow of fuel to it will be carried out in the required quantity.
If there is excessive air leakage, then the engine may also stall. You should increase the speed a little so that air bubbles come out of the fuel system. It is also worth checking the integrity of the fuel intake hose. If any damage is found in it, the part must be replaced immediately.
Filter malfunction
Air and fuel filters are inspected. If the blockage is severe enough, it needs to be replaced with another one. The air filter can be washed with water and a special product, followed by drying the unit.
You can also soak it in gasoline. It is important, after installing the filter, to moisten it with the same oil that is mixed with fuel.
If the engine does not start
When the lawn mower does not start, you must first check to see if the fuel in the tank has run out. If everything is in order, then you need to check its quality - perhaps you purchased a cheap type of gasoline that is not suitable for the equipment. For the scythe, it is best to use good gasoline, which is purchased at gas stations; the grade should be at least AI-92.
You should not save money and purchase cheap fuel, as this will lead to the cylinder-piston group failing , and you can spend much more money on repairs than on high-quality gasoline.
It is also very important to prepare the fuel mixture correctly and combine oil and gasoline in the right quantity. The proportional ratio must be specified in the manual. That is why it is so important that it is written in Russian, because it is likely that different mower models require slightly different proportions for successful operation.
There is no need to use the fuel mixture in large volumes, since if the unused volume is stored indoors for a long time, it will lose its properties. It is better to use a freshly prepared solution.
- A problem with engine operation can be contamination of the fuel filter. First of all, you have to check the filter. If necessary, replace it. Under no circumstances should the inlet pipe be left without a fuel filter. It’s also worth checking the air filter at the same time. If it gets dirty, you need to remove it, wash it in gasoline and put it back in place. If you are at the dacha or in a private house, then it will be enough to rinse it in clean water, using various detergents. After this, rinse, wring out and let dry. The finished filter is moistened in a small amount of oil, which is used to prepare the mixture. Excess is removed by squeezing the filter with your hands. Then the part can be put back.
- If all these procedures did not help and the engine still does not start, then you can try to adjust the idle speed, to do this, start tightening the carburetor screw. This is very similar to tuning a similar part on a car. If you have no experience in adjusting the carburetor, then you can study videos on the Internet, which are very clear and accessible. There they will clearly show how you can adjust the carburetor of a lawn mower with your own hands.
Stalling lawn mower after starting
The documentation provided when purchasing the unit contains an algorithm for adjusting the carburetor. Following the instructions, you need to configure the node correctly. In some cases, it is necessary to loosen the carburetor valves to facilitate fuel injection.
Another reason for instrument jamming is excessive air intake. In this situation, it is necessary to increase the engine speed to expel excess air.
In addition, there may be damage to the shell of the hose through which the fuel flows. If damage is found, the hose must be replaced.
How to start a gasoline trimmer: 3 beginner mistakes
Confidence in oneself, one's own strengths, knowledge and skills is a characteristic feature of a Russian person. It manifested itself in both of my experienced neighbors when they began to use an unknown brand of lawn mower as their usual gasoline-powered tool.
Do not repeat this mistake, first carefully read the instructions specially written for us by the manufacturer. Only after understanding it can you start a lawn mower.
The rules for starting my trimmer design are shown in text and a visual picture in the manufacturer's manual.
Compliance with the specified sequence of actions will allow you to operate the lawn mower for a long time. They are important to remember.
The primer (hand pump) pumps fuel into the carburetor lines. First press the button several times. Without this, the lawn mower will not start.
The trimmer control is concentrated on the right handle with a throttle valve, which performs the following functions:
- lever for blocking button positions from accidental switching;
- gas control keys;
- mode switch:
- cold start;
- working position;
- stop.
It is convenient to do all this simultaneously with the palm and fingers of the right hand. I show the basic techniques in the photo.
The ignition is turned on automatically. There is no external button; it is locked inside the handle with the position of these switches and is not specially displayed.
Special mention should be made about the clutch. It separates the trimmer drive and its motor. The clutch is controlled automatically: when the engine starts after pressing the gas button.
When starting the lawn mower, its body must be positioned so that if the clutch is accidentally engaged, it does not cause harm to people, animals and surrounding objects. Rotating working parts: a mowing head with a fishing line, and even more so a knife, can create serious problems.
My specialist assistants, working with other designs of gasoline engines, did not know all the nuances of operating my model and simply poured fuel into the combustion chamber.
A flooded spark plug receives an anti-spark barrier. When the spark is missing or weakened, the engine will not start.
The trimmer can have two states before starting:
- cold when it has not yet been used;
- hot – after a short stop during operation (did not have time to cool down).
Cold start of a two-stroke trimmer engine
It is this that is shown in pictures and text in the factory instructions given above. For this, it is necessary to create a small supply of a rich working mixture above the piston.
For this purpose, the air flow is blocked by a damper, and fuel is supplied in the right position of the control handle mode switch. The swap primer is pressed.
The fuel mixture is pumped through the carburetor several times by rotating the crankshaft using the starter cord. After this, the choke lever is moved down to the “Open” position.
All that remains is to move the piston up to compress the gases and ignite them with a spark from the spark plug, which is done once again with a manual starter.
How to start a hot brush cutter
Here you need to pay attention to the fact that the trimmer is turned off by moving the handle switch forward: the fuel supply to the cylinder head is cut off. It will need to be installed in the middle.
No action is taken on the air damper; it remains open.
The temperature inside the cylinder is still high; when the fuel mixture is injected there, gasoline ignites well from a spark plug; there is no need to enrich anything.
To start a hot trimmer engine, it is enough:
- set the handle switch to the middle “Work” position;
- select free play and pull the recoil starter cord evenly.
The gas mower starts. If this technology is violated, fuel will flood the spark plug and the engine will not start.
What to do if a spark plug is filled during a cold engine start and it does not start
Gearbox
Repairing a gearbox at home is not always convenient. If the gearbox or starter breaks down, you will most likely need to replace them with others.
To prevent this, it is important to keep the knot in order. The gears must be constantly lubricated with a special substance.
Weakening of the motor
A clogged exhaust muffler mesh can lead to a drop in engine power. The blockage comes from soot, which is a product of burnt oil.
The mesh should be cleaned with a metal or nylon brush, or with an air stream.
Checking filters
Another common reason why the trimmer will not start is if there is a clog in the filter area. To confirm your guess, it is enough to dismantle the indicated block and try to start the unit without it. If the trimmer engine starts, most likely you will have to replace the air filter or at least thoroughly blow out the old one. If there is heavy contamination on the surface of the filter element, it is necessary to use a new mesh. When resorting to such actions, you should not leave the suction pipe completely without a filter. After all, haste in this case can lead to the need to repair the entire piston group of the unit’s engine.
Often, the engine of branded trimmer models stalls as a result of a clogged breather. The main task of this component is to equalize the pressure in the fuel tank. Why the engine won't start: 2 Why the gasoline trimmer won't start. (Patriot). If the unit becomes dirty, a vacuum is formed here, which significantly complicates the supply of fuel. The problem can be resolved by cleaning the breather using a regular sewing needle.
Clutch
Worn pads or a broken spring will cause the clutch to malfunction. In both cases, it is necessary to replace the broken parts. The clutch can also fail. It should be replaced.
Spare parts for beznokos are sold freely in specialized stores.
Recommendations from professionals
It is very easy to prevent the working tool from breaking. The most important thing is to study the operating instructions for the unit. When working with a trimmer, it is necessary to monitor the cooling process of the motor.
It is important to keep the cylinder fins and starter clean. If the engine overheats, it can quickly fail.Preventive maintenance of your lawn mower significantly extends its service life. It is enough to periodically inspect and clean the engine. The engine is washed with a soft bristle brush.
It is strictly forbidden to leave fuel in the tank for more than a month. It is recommended to drain the fuel if there is no need to operate the mower during this period.
It is also not recommended to use diesel or gasoline of lower quality than 92. It must be mixed with two-stroke engine oil.
It is strictly contraindicated to mix different types of fuel - this will inevitably lead to malfunctions.
When cold weather arrives, it is recommended to prepare the unit for long-term storage. Be sure to drain all fuel. Start the engine to remove any remaining mixture in the carburetor.
After this, the equipment should be thoroughly cleaned. With proper care of your lawn mower, a unit from any manufacturer will last as long as possible.
Repair and lubrication of the gearbox with a brush
The role of the gearbox is to transmit torque from the motor shaft to the cutting tool through 2 gears with different numbers of teeth. Torque is transmitted at an angle of 30 0. The speed of the lower cutting disk is 1.4 times less than the engine speed. The mechanisms must be clean and lubricated. Under the screw there is a hole for supplying oil to the teeth from above.
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First, the area where the plug covers the hole must be cleared of soil and grass. We unscrew the plug using a suitable tool; it is attached to the saw. We use pipe oil. Either native lubricants from the manufacturer, or well-known high-quality compounds, such as Oleo-Mas, Litol. 24, Azmol 158 selected. Open the protective layer of the tube and place the instrument on its side. Slowly turning the knife, squeeze the oil into the gearbox housing. Gear wheels, rotating, dilute the composition of the teeth over the entire surface. You can also fill the oil using a special syringe.
Too little or too much fat can cause the transmission to heat up. The sound knocks and plays signals that the bearing is damaged or dirty due to damage to the sawmill. Bearings must be replaced with a puller without using a heating method.
If the transmission rocks and moves on the boom, the housing will need to be replaced or the assembly may need to be temporarily tightened with a clamp to secure it to the pipe. If the blade does not rotate, the gears will not mesh. teeth are worn or crumbling. You will need to replace the pair with a full node analysis.
When replacing a gearbox, you must select a new unit, guided by:
- Pipe diameter;
- Drive shaft diameter;
- Drive shaft section;
- Ways to attach protection
Photo of brush cutters
Total
Category: Instructions
