Carburetor Trimmer Setting
When adjusting the carburetor of the household trimmer is 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 weather changes;
- Changes in air pressure. for example, when the lawnmower is often used in mountainous areas;
- Prolonged simple trimmer;
- Intensive growth of loads on the power unit of lawn mowers;
- Arbitrary unscrewing of the built-in adjusting screws of the carburetor. this causes increased vibration of the internal combustion engine;
- Changes in the quality of the components of the fuel mixture;
- Overflowing 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;
- Engine start and its arbitrary shutdown or slow speed set;
- Lack of fuel flow into the cylinder of the power unit;
- Increase in the volume of emitted exhaust gases.
The lack of timely adjustment of the carburetor threatens serious damage to the trimmer, up to the complete failure of its factory engine.
Lawn mowers carburetor device
The standard design of any gasoline trimmer necessarily includes a fuel system, the basis of which is the action of a standard carburetor. Its design and initial principle of operation are almost the same for all lawn mowers, regardless of their design features and purpose.
The lawn mowers carburetor consists of an all-metal aluminum housing that protects the internal components of the unit from moisture, small debris and dust. In the lower part of the body there is a built-in diffuser, the second name of which is “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 the air is sucked in. This is due to the fact that in the area 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 device of the carburetor of lawn mowers includes a throttle valve, the main task of which is to regulate the volume 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 this is the first time the mower is started after a long period of inactivity, the shutter must be closed. Immediately after starting the engine, 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 engine creates a reciprocating motion, 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 built-in intake and exhaust valves, then through the strainer and fuel pipe. The fuel then flows next to the needle and gradually fills the chamber equipped with the control diaphragm.
The standard carburetor trim valve is connected to the diaphragm using a lever. Below the built-in membrane is a cavity into which air is sucked in through a special opening.
The lawn mower carburetor 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.
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. a built-in carburetor is responsible for this in the basic device of the lawn mower. 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.
DIY lawn mowers 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 lawn mower design.
The lawn mower engine must be running under a certain load when adjusting the carburetor. 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 internal combustion 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" one by one 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, it will accordingly 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. After that, the screw "H" will need to be turned 1/2 turn to the left.
Performing these steps one by one will allow you to correctly configure the fuel trimmer assembly, without the risk of exceeding the permissible load on its main working mechanisms.
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 supply adjustment screw ("L");
- High speed adjustment screw ("H");
- The screw is responsible for the engine idling ("T" or "AT").
Fuel supply adjustment at minimum speed
Before starting tuning the carburetor of the gas trimmer, it is required to warm up the engine to operating temperature.
Fuel adjusting screws
To do this, we start the internal combustion engine and, at idle, let it run for 10-15 minutes. In the first step, with the trimmer running, slowly tighten the screw "L" until the start of intermittent operation or until it stalls. Next, unscrew the screw ¼ of a turn and check the maximum speed set. If the lawn mower reaches high revs easily and quickly, this will be the most economical mode. In most of the models on the market, the fuel screw "L" is turned clockwise, but there are trim tabs where the decrease and increase in the supply of the mixture occurs in the opposite order.
Adjusting the maximum speed screw for lawn mowers
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 to reduce hand fatigue when pressing the accelerator button. If the internal combustion engine is unstable at maximum speed, the screw "H" must be tightened slowly until smooth and precise operation is ensured.
During operation of the lawn mowers it may be necessary to adjust the fuel screw ("L") for the optimal set of revolutions.
Carburetor Adjustment Lawn Mowers Highlights
Despite their high productivity, mobility and unpretentious work, modern lawn mowers can hardly be classified as 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 the fuel mixture and feed it into the combustion chamber. Increased consumption with proper respect for the proportions of gasoline and oil or a drop in engine power indicate the need to adjust the carburetor of the gasoline trimmer.
Adjusting the idle trimmer
Location of carburetor adjustment screws
The screw "T" ("AT") serves as a limiter for the reciprocating movement of the fuel flap and when it is tightened, the engine speed increases, while loosening it leads to a decrease in the crankshaft speed. Professionals advise adjusting the idle screw of lawn mowers so that the internal combustion engine runs a little faster at minimum speed, but the head with a fishing line or knife remains stationary. If after the performed 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.
Gas trimmer carburetor repair tips
- Regardless of the manufacturer, there is a factory defect in the carburetor parts of the lawn mowers.
Adjusting screw spring
For example, the tuning method described above may not give positive results if the number of turns at the spring of the screw for supplying the mixture is too large and, as a result, the impossibility of optimally reducing the level of supplied gasoline. To eliminate this, you can shorten the spring yourself a little or, in accordance with the operating manual, purchase a new one.
Many lawnmower owners follow the fuel mixture recommendations listed there when buying oil.
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 oil portion and the formation of carbon deposits on the spark plug with an increased amount of lubricant.
The diffuser is equipped with fuel channels. Fuel is drawn from them using a stream of air.
Outside the carburetor is installed:
- Fuel pump;
- Jet system;
- A system for adjusting the consistency of fuel with air;
Adjusting the carburetor trimmer Husqvarna 128r
Self-adjustment of the carburetor for lawn mowers with your own hands is impossible without preliminary work, knowledge of the theory, awareness of the fuel system. Annotation for the repair of the carburetor.
Adjusting the carburetor Husqvarna lawn mowers 125, 128
Principle of operation
A 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 for lawn mowers is the same for almost all cases. It belongs to the category of float devices. The latter provide stable parameters of ready mixes.
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 hole for the gasoline supply is formed, the tube has a narrowing. a diffuser. Here the flow rate increases.
- Fuel from the float chamber is fed through the nozzle into the tube. Carburetor device for lawn mowers. Setting up the carburetor kraftk lawn mowers. 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 more fuel enters the cylinder. Setting up the carburetor for lawn mowers is reduced to setting such a ratio of flaps at which the density of the fuel mixture becomes optimal.
When does the carburetor of a Husqvarna chainsaw need adjustment?
There are a lot of problems that can be solved by adjusting the carburetor. Adjusting the carburetor of your Husqvarna chainsaw is necessary when such malfunctions appear:
- Increased idle speed;
- Strong fuming during tool operation;
- Difficulty starting a cold or hot engine;
- Lack of traction and lower maximum rpm.
This is by no means a complete list of problems that can be solved by tuning the Husqvarna carburetor. In some cases, the quality and quantity of the fuel mixture is adjusted after an engine overhaul or in the process of scheduled maintenance of the chainsaw.
Husqvarna AB recommends adjusting the carburetor before and after running in.