Chinese Trimmer Carburetor Adjustment
Carburetor for trimmer: device, do-it-yourself tuning When do you need to adjust the carburetor of a household trimmer? Carburetor device benzos, do it yourself carburetor adjustment
Carburetor device gas cutters
The standard design of any gasoline trimmer necessarily includes a fuel system, the basis of which is the action of a regular carburetor. Its structure and initial principle of operation are practically the same for all brushcutters, regardless of their design features and purpose.
The brushcutter carburetor consists of an all-metal aluminum housing that protects the internal components of the unit from moisture, fine debris and dust. In the lower part of the body there is a built-in diffuser, the second name of which is the Venturi nozzle. The main function of this standard part is to supply air in the amount required by the fuel unit to enrich the fuel. A diffuser works according to a simple principle: the smaller its diameter becomes, the more intensively air is sucked in. This is due to the fact that in the zone of the smallest diameter the level of air vacuum becomes maximum.
The upper part of the built-in factory diffuser is pre-equipped with fuel pipes, through which, under the influence of air, the fuel mixture is drawn in. The rest of the carburetor parts: standard adjusting screws and a fuel pump, can be located both inside and outside the carburetor.
The carburetor device of the brushcutter includes a throttle valve, the main task of which is to regulate the volumes of intake air. The larger the amount of air, the higher the rated power of the trimmer power unit. Another function of the damper is to facilitate cold starting of the engine. If the brushcutter starts up for the first time after a long period of inactivity, the shutter must be closed. Immediately after starting the motor, the part must be opened, otherwise the internal combustion engine will stall.
The carburetor for the trimmer is equipped with an impulse channel that connects the internal cavity of the engine crankcase with the impulse chamber of the pump. The piston located in the cylinder of the motor creates reciprocating movements, which leads to gradual changes in pressure inside the crankcase. At the same time, the membrane is set in motion. Thus, the action of the pump is fully synchronized with the operation of the power unit.
The diaphragm of the standard carburetor takes an active part in the suction of fuel. It enters the fuel unit through the fitting. The fuel then flows through the integrated inlet and outlet valves, then through the strainer and fuel pipe. The fuel then flows near the needle and gradually fills the chamber equipped with the control diaphragm.
The standard carburetor trim valve is connected to the diaphragm with a lever. Below the built-in membrane is a cavity into which air is sucked in through a special opening.
The carburetor for petrol cutters works on this principle in stages. This ensures continuous operation of the fuel unit and uninterrupted fuel supply to the cylinder of the standard power unit.
When is the carburetor setting of the household trimmer required?
Adjust the built-in trimmer carburetor when:
- Running in a new engine, during which 4 to 5 liters of fuel mixture were used;
- Sudden changes in weather;
- Changing the air vacuum, for example, when the brushcutter is often used in mountainous areas;
- Long-term simple trimmer;
- Intensive growth of loads on the power unit of brushcutters;
- Arbitrary unscrewing of the built-in carburetor adjusting screws, this causes increased vibration of the internal combustion engine;
- Changes in the quality of the components of the fuel mixture;
- Pouring fuel with a carburetor, resulting in an increase in fuel consumption;
- The regular appearance of a thick layer of resinous deposits and carbon deposits on the surface of the electrodes of a standard trimmer spark plug;
- Starting the engine and its arbitrary shutdown or slow set of revolutions;
- Lack of fuel flow into the cylinder of the power unit;
- An increase in the volume of emitted waste gases.
The lack of timely adjustment of the carburetor threatens with serious damage to the trimmer, up to the complete failure of its factory engine.
Carburetor for trimmer: device, do it yourself setting
Stable and efficient operation of a household trimmer largely depends on the quality of the fuel used by the operator. The filled fuel mixture must be enriched with air for this in the basic device of the brushcutter, the built-in carburetor is responsible. This knot is one of the main elements of the streamer, so the operator must constantly monitor its serviceability and settings. Otherwise, the trimmer will lose its performance and may completely fail.
Do-it-yourself carburetor adjustment
Periodic adjustment of the trimmer carburetor should be performed on a serviced and fully serviceable power unit. Before starting the procedure, the operator must thoroughly rinse the internal combustion engine parts and inspect its CPG for burrs or other defects. In addition, you will need to clean or change the spark plug, as well as rinse the filter elements in the brushcutter design.
When adjusting the carburetor, the brushcutter engine must operate under a certain load. It is best to install a cord of the appropriate diameter or cutting knives on the trimmer.
After installing the cutting elements, the operator should start the engine of the trimmer and leave it to work for about 10 minutes. If, during the operation of the power unit at idle, it was noticed that the cord or knife rotated, then it is necessary to reduce the speed generated by the motor. To do this, turn the lower adjuster, often marked with the letter T, to the left until the installed cutter comes to a complete stop.
Further configuration of the fuel assembly is as follows:
- The L regulator, located on the right, is responsible for enriching the fuel mixture with air when the engine is running at low speeds. The position of this screw must be adjusted first. To do this, the operator will need to achieve maximum engine speed when idling, to do this, turn the screw L alternately to the right or left. Once the maximum speed is reached, the screw will need to be turned 1/2 turn to the left;
- The T or LA screw is required to adjust the idle speed. While turning it to the left, the speed of the power unit will decrease, and when turning to the right, accordingly, it will increase;
- The regulator H, provided on the left, is responsible for enriching the fuel mixture with air when the internal combustion engine trimmer is running at high rpm. This screw is also needed to adjust the engine power and the amount of fuel consumed. Its position is adjusted by turning the screw to the right or left side until the maximum permissible engine speed is reached. Then screw H will need to be turned 1/2 turn to the left.
Performing these steps one by one will allow you to correctly adjust the fuel trimmer assembly, without the risk of exceeding the permissible load on its main working mechanisms.
Principle of operation
The carburetor is a power system module in which liquid fuel and air are mixed before being fed into the engine cylinders. Mixing and feeding are adjusted accordingly depending on the tool and its mode of operation.
The carburetor device is the same in almost all cases. It belongs to the category of float devices. The latter provide stable parameters of ready-made mixtures.
The principle of the module is as follows.
- Air enters the body of the air damper tube. The latter increases or decreases the air flow depending on its position.
- In the area where the gasoline feed hole is formed, the tube has a narrowing diffuser. Here the flow rate increases.
- Fuel from the float chamber is fed through the nozzle into the tube. The float level determines the amount of fuel supplied. Since the pressure in the chamber is normal, and in the tube it is low due to the greater rarefaction of the air, gasoline is sucked in through the nozzle.
- The accelerated air flow picks up the fuel and sprays it, forming an air-fuel mixture of the desired density.
- The mixture is sucked into the cylinder through the pipeline.
The more open the air damper in the tube, the higher the density of the air flow, which means that more fuel enters the cylinder. Setting up the carburetor of a petrol scooter is reduced to setting such a ratio of flaps at which the density of the fuel mixture becomes optimal.
Signs of imbalance
Debugging the carburetor must be done during the manufacture of the device. As a rule, the owners will learn about the need to adjust the fuel supply with their own hands only after serious enough breakdowns, in the process of correcting which, the module was removed and, for example, cleaned.
The following are the symptoms of a configuration failure:
- Starts, but the engine immediately stalls, since the engine can only work when a certain amount of gasoline is supplied, with too lean fuel, that is, blocking the supply channel, the engine will stop;
- Too high fuel consumption, a lot of exhaust gases are the result of incomplete combustion of the mixture. In this case, on the contrary, there is too much fuel and the mixture is too dense.
Adjustment and repair of the carburetor gas cutters
The trimmer does not belong to complex household appliances, therefore most of its breakdowns are mechanical in nature and are quite successfully eliminated with their own hands. Even if the engine fails for serious reasons, damage to the piston ring, for example, repairs is reduced to replacing a part.
But even with a relatively simple design, such a part of the device as the carburetor needs to be adjusted.
Do-it-yourself carburetor adjustment
Setting up the module does not apply to repair and replacement of spare parts is not required. In this case, the carburetor repair kit for the brushcutter is not needed.
Three screws are provided for debugging:
- L is regulated first, as it is responsible for supplying fuel at low revs;
- H he is responsible for the supply of gasoline at high rpm, as well as for fuel consumption and temperature;
- T it is used to debug idle.
There are options, as a rule, this is the carburetor of a Chinese petrol cutter, when only one screw remains on the body for debugging to adjust the idle speed. This does not mean that the module is configured automatically, it means that it will be difficult to carry out even such a kind of repair as debugging. To adjust the carburetor of a Chinese petrol cutter.
- The module is configured only when the engine is warm: for this, the device is pre-switched on for 10 minutes. If the mowing head rotates while idling, the debugging is started immediately: turn the screw T counterclockwise until the rotation stops.
- Adjustment begins with screw L. The screw is turned to the right and left until it is in such a position that the idle speed does not become maximum.
- Then the screw is turned counterclockwise ¼ turn. This will be his working position.
- Idling must be adjusted by turning counterclockwise to increase the number of revolutions and clockwise to decrease it. Its debugging consists in achieving such a mode in which a sufficient number of revolutions are made before the start of rotation of the mowing head. In this case, the engine must work stably in different positions.
- The position of screw L is determined by the last at maximum speed, the trimmer should not work for more than 10 seconds. The throttle opens, the screw turns clockwise, very slowly, until a decrease in the number of revolutions is audible.
- Then, also slowly, the screw rotates counterclockwise until the motor begins to malfunction. Then the screw is turned back clockwise until the engine starts working normally again.
If there is a tanometer, and if the recommended rpm values are indicated in the product passport, the correction can be made more accurate, focusing not on hearing, but on the readings of the device.
Adjusting the fuel supply at minimum speed
Before you start tuning the carburetor of the petrol trimmer, you need to warm up the engine to operating temperature.
Fuel adjusting screws
To do this, start the internal combustion engine and let it run for 10-15 minutes at idle speed. In the first step, with the trimmer running, slowly tighten screw L until intermittent operation starts or until it stalls. Next, we unscrew the screw орота of a turn and check the speed of a set of maximum revolutions. If the brushcutter quickly and easily reaches high revs, this will be the most economical mode. In most of the models on the market, the fuel screw L is turned clockwise, however, there are trimmers where the decrease and increase in the mixture flow occurs in the opposite order.
Adjusting the carburetor gas cutters: highlights
Despite the high productivity, mobility and unpretentiousness in work, modern brushcutters can hardly be attributed to complex devices. Over time, any mechanism is subject to wear and tear, and therefore parts and assemblies require special attention from the owner. One of these trimmer elements is the carburetor, designed to form a fuel mixture and feed it into the combustion chamber. Increased consumption, with proper observance of the proportions of gasoline and oil, or a drop in engine power indicate the need to adjust the carburetor of the gasoline trimmer.
Carburetor Trimmer Adjustment
The initial step in restoring the correct operation of the fuel system is to clean the air filter.
Trimmer carburetor with screws
Experts recommend rinsing it in a solution of water and detergents after every 10-15 hours. Direct adjustment of the carburetor trimmer is done with three adjusting screws:
- Fuel adjustment screw (L);
- High speed adjustment screw (H);
- The screw responsible for the engine idling (T or AT).
Adjusting the idle trimmer
Location of carburetor adjustment screws
The T (AT) screw serves as a limiter for the reciprocating movement of the fuel flap and when it is tightened, the engine rpm increases, and loosening leads to a decrease in the engine speed. Professionals advise to adjust the idling screw of the petrol cutter so that the internal combustion engine runs a little faster at minimum speed, but the head with the line or knife remains motionless. If after these manipulations it is difficult to start the trimmer to cold, then it is enough to tighten the screw T a quarter of a turn and try to start the engine again.
Adjusting the screw for the maximum speed of the brushcutter
After restoring the fuel supply at minimum speed and adjusting the idle speed, it is necessary to check the stability of the mechanism at an increased speed.
Tuning at maximum speed
The motor is adjusted at high speeds in order to protect against overheating and reduce hand fatigue when pressing the accelerator button. If the internal combustion engine is unstable at maximum speed, screw H must be tightened slowly until smooth and precise operation is ensured.
While the brushcutter is in use, it may be necessary to adjust the fuel screw (L) for optimal speed gain.
Gas trimmer carburetor repair tips
- Regardless of the manufacturer, there is a factory defect in the carburetor parts of the petrol cutter.
Spring for adjusting screw
For example, the tuning technique described above may not give positive results if there is an excessively large number of turns at the spring of the screw for supplying the mixture and, as a consequence, the impossibility of optimally reducing the level of supplied gasoline. To eliminate this, you can independently shorten the spring a little or, in accordance with the operating manual, purchase a new one.
When buying oil, many owners of petrol brushes follow the recommendations for preparing the fuel mixture indicated there.
Petrol trimmer oil
So, often the information on mixing gasoline with oil indicated on the bank differs from the instructions in the trimmer passport. As a result, black carbon deposits can quickly build up on the spark plug, leading to a drop in power and increased fuel consumption. Therefore, when preparing the working mixture, you should follow the recommendations specified in the operating manual. In most cases, the proportion for a run-in ICE is 1:25. It is worth noting that many tool owners prefer to prepare fuel by eye, which will certainly lead to rapid wear of the piston streamer in the event of a decrease in the portion of oil and the formation of carbon deposits on the spark plug with an increased amount of lubricant.
- Tips for setting up the trimmer carburetor correctly performed above will help to avoid not only engine overheating, increased fuel consumption, but also significantly increase the service life of other parts and assemblies of the tool. Pay attention to the operation of the brushcutter in all modes and carry out the regulated maintenance and repair of the tool in time.
Adjustment of the carburetor, trimmers, trimmers
Increased fuel consumption and the rapid formation of carbon deposits on the brushcutter candle when using a properly prepared fuel mixture indicate the need to adjust the carburetor. Here’s how to tune trims with carburettors that have a single fuel adjusting screw.
I read somewhere that if different proportions of preparation of the fuel mixture are indicated in the manual for the petrol cutter and on the oil canister, the proportion indicated in the manual should be used.
For a long time, it did so from the engine to the gas tank, excess oil flowed down and carbon deposits constantly formed on the candle, since the manual indicated the proportion for the run-in engine 1:25, and on the canister 1:50. After switching to a 1:50 ratio, the appearance of oil drips stopped. The plug continued to burn, but with less intensity (the carburetor was not yet adjusted).
Until now, some users of gasoline tools determine the proportion of the fuel mixture by eye. If during the preparation of the mixture the amount of oil is underestimated, after a while an extraneous sound may appear immediately after starting the engine, gradually disappearing during warming up, and the engine stops with a sharp jerk. Continued use of the trimmer in this mode will lead to its failure.
Gas cutter or trimmer
A trimmer is a broader concept than a brushcutter (brushcutter), since it can also be electric. A petrol trimmer and a petrol cutter are one and the same.
Some authors claim that the trimmer is a weaker tool in contrast to the more powerful petrol cutter, which can be used for cutting bushes. Personally, I have a tool with a maximum power of 1.7 kW and is capable, as stated in the instructions, to mow small bushes up to 10 mm thick. The user manual is called Petrol Trimmer.
Fuel supply adjustment
Begin to slowly tighten the fuel mixture adjustment screw until the engine starts to stall or stalls if you do not have time to catch the moment. After that, unscrew the screw a quarter of a turn if the engine has not stalled, or half a turn if it stalled. Start the stalled engine. Check by opening the throttle as the engine picks up speed. Continue to unscrew screw # 1 by a quarter of a turn until the engine starts to accelerate steadily during gas blowing. This will be the moment of the most economical stable engine operation. For the PRORAB-8406 gasoline trimmer, the adjusting screws are turned clockwise, unscrewed counterclockwise, for some other brands of the petrol cutter it may be the other way around.
Maximum speed limitation
After adjusting the fuel mixture and low speed, check how the petrol cutter engine will operate at maximum speed. If necessary, limit the maximum RPM to the required level with the # 3 hollow screw. Loosen the retaining nut and turn in the screw to decrease the maximum speed or turn it out to increase it. Tighten the nut after adjustment. The maximum RPM setting is necessary to protect the trimmer motor from overheating and to be able to use the start key lock to reduce right hand fatigue.
In the future, it may be necessary to adjust the trimmer carburetor. For example, if the engine starts to rev poorly when running at full load, loosen screw # 1 another quarter turn. If starting is difficult, increase idle speed. Both weather conditions and the quality of the fuel mixture can affect the operation of petrol mowers. Vibration can cause the adjusting screws themselves to turn.
The main problems and malfunctions of the carburetor.
Mesh filter. There are often only two problems with this element:
In order to find out the cause of the breakdown, the fuel filter cap is unscrewed to remove the strainer. If dirt simply accumulates on it, then flushing in gasoline or blowing will help.
If there is visible damage to the strainer, it is imperative to install a new one. There may also be damage to the fuel supply pipe (during repair, they practice checking this element).
The carburetor starter in most cases does not function due to blockages. Use acetone or the same gasoline for flushing.
Blowing compressed air into carburetor parts is an acceptable and convenient repair practice.
Do-it-yourself carburetor adjustment for petrol cutters
Petrolcutters, like all petrol powered tools for the garden, are not difficult to maintain. It is possible and necessary to repair, configure yourself. For example, adjusting the carburetor of a petrol cutter with your own hands is a matter of five minutes.
The carburetor from the petrol cutter is a unit in the power system. In it, like any carburetor, there is a process of mixing air and fuel (gasoline) for further supply to the engine cylinders.
Carburetor device gas cutters
The base of the carburetor is an aluminum case. It contains a diffuser (hole with inner contours). Air is blown through this hole. The flow rate of oxygen (air) depends on the cross-section (orifice) of the diffuser.
The diffuser is equipped with fuel channels. Fuel is drawn in from them using an air stream.
Outside the carburetor is installed:
- Fuel pump;
- Jet system;
- Fuel-air mixture control system;
The principle of operation of the carburetor petrol cutters
The throttle valve determines the amount of air to be supplied, and the engine power directly depends on this.
Fuel is sucked into the carburetor system by a pump (its membrane). Then it passes through the union in the carburetor. The fluid then flows through the pump inlet and outlet valves. Filtered by the grid. It moves through the needle valve into the membrane chamber.
Phased operation of the device:
- Air supply to a tube with an air baffle (damper). The baffle regulates the intensity of the air flow.
- The fuel supply system is necessarily narrowed by a diffuser to increase the flow rate.
- Gasoline through the float chamber and the nozzle tube with a constriction. A float chamber adjusts the temporary volume of gasoline. In the float chamber, the pressure level is neutral, and in the tube with a constriction it is already low. Due to the differential pressure, the fuel flows through the jet.
- The acceleration of the air flow facilitates the transfer of fuel (gasoline) and its atomization. As a result, an air-fuel mixture of the required proportion or density is formed.
- The air / fuel mixture enters the engine cylinder through the fuel pipe.