The stable and effective operation of the household trimmer is largely dependent on the quality of the fuel used by its operator. The filled fuel mixture must be enriched with air. for this, the built-in carburetor is responsible for this in the basic lawn mowing device. This node is one of the main elements of the braid, so the operator must constantly monitor its serviceability and settings. Otherwise, the trimmer will lose its performance and may completely fail.
The device of the carburetor lawn mowers
The standard design of any gas trimmer must include a fuel system, the basis of which is the action of a standard carburetor. Its structure 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 assembly from moisture, small debris and dust. A built-in diffuser is provided in the lower part of the body, 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 assembly to enrich the fuel. The diffuser operates according to a simple principle: the smaller its diameter becomes, the more intensively the air is absorbed. This is due to the fact that in the zone of the smallest diameter the level of air discharge 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. Other carburetor parts: regular adjusting screws and a fuel pump, can be located both inside and outside the carburetor.
The carburetor of the lawn mowers includes a throttle, the main task of which is to regulate the amount of intake air. The greater the amount of air, the higher the rated power of the trimmer power unit. Another function of the damper is to facilitate the cold start of the engine. If the lawn mowing is started 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 engine will die out.
The carburetor for the trimmer is equipped with a pulse channel that connects the internal cavity of the ICE crankcase with the pulse chamber of the pump. The piston located in the cylinder of the motor creates a reciprocating motion, which leads to gradual changes in pressure inside the crankcase. At the same time, the membrane is driven. Thus, the action of the pump is fully synchronized with the operation of the power unit.
The membrane of a regular carburetor takes an active part in fuel suction. It enters the fuel assembly through the fitting. After that, the fuel passes through the built-in intake and exhaust valves, then through the strainer and the fuel pipe. Then the fuel flows next to the needle and gradually fills the chamber equipped with a control membrane.
The regular valve of the trimmer carburetor is connected to the membrane using a lever. Below the built-in membrane is a cavity into which air is drawn in through a special opening.
The carburetor for lawn mowers works on this principle in stages. This ensures uninterrupted operation of the fuel unit and uninterrupted supply of fuel to the cylinder of a standard power unit.
When is the carburetor adjustment of a household trimmer required?
Adjust the built-in trimmer carburetor when:
- running-in of a new engine, during which from 4 to 5 liters of fuel mixture were used;
- sudden changes in weather;
- changes in rarefaction of air. for example, when the lawn mowing is often used in mountainous areas;
- long simple trimmer;
- intensive growth of loads on the power unit of lawn mowers;
- arbitrary unscrewing of the carburetor’s built-in adjusting screws. this becomes the cause of increased vibration of the internal combustion engine;
- changing the quality of the components of the fuel mixture;
- fuel transfusion with a carburetor, resulting in an increase in fuel consumption;
- regular appearance of a thick layer of tarry deposits and soot on the surface of the electrodes of a regular trimmer spark plug;
- engine start and its arbitrary shutdown or a slow set of revolutions;
- the lack of fuel in the cylinder of the power unit;
- increase in exhaust emissions.
Video: Carburetor Trim Adjustment Wrench
The lack of timely adjustment of the carburetor threatens serious damage to the trimmer, up to the complete failure of its factory engine.
DIY carburetor adjustment
Periodic adjustment of the trimmer carburetor should be performed on a serviced and fully functional power unit. Before starting the procedure, the operator must thoroughly rinse the engine parts and inspect its CPG for any burrs or other defects. In addition, you will need to clean or replace the spark plug, as well as rinse the filter elements in the construction of the lawn mowers.
During carburetor adjustment, the lawn mowing engine must run under a certain load. It is best to install a cord of the appropriate diameter or cutting knives on the trimmer.
After mounting the cutting organs, the operator should start the internal combustion engine trimmer and leave it to work for about 10 minutes. If during operation of the power unit at idle it was noticed that the cord or knife rotate, then you need to reduce the speed created by the motor. To do this, turn the lower control, often denoted by the letter “T”, to the left, until the installed cutting unit stops completely.
A 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 while the engine is operating at low revs. The position of this screw must be set first. To do this, the operator will need to achieve maximum engine speed when idling. for this you need to turn the screw “L” in turn to the right or left side. Once the maximum speed is reached, the screw will need to be rotated 1/2 turn to the left;
- Screw “T” or “LA” is required to adjust the idle speed. During its rotation to the left, the revolutions of the power unit will decrease, and when turning to the right. accordingly, increase;
- The “H” regulator, provided on the left, is responsible for enriching the fuel mixture with air during the operation of the engine trimmer at high speeds. This screw is also needed to adjust motor power and fuel consumption. Its position is adjusted by turning the screw to the right or left side until the maximum permissible engine speed is reached. After that, screw “H” will need to be turned 1/2 turn to the left.
The sequential implementation of these actions will allow you to correctly configure the trimmer fuel assembly, without the risk of exceeding the permissible load on its main operating mechanisms.
lawn mowers, like all gasoline 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 the lawn mowers with your own hands is a matter of five minutes.
Lawn mowing carburetor is a unit in the power system. In it, like any carburetors, there is a process of mixing air and fuel (gasoline) for further supply to the engine cylinders.
The main problems and malfunctions of the carburetor.
Strainer There are only two problems with this element:
In order to find out the cause of the breakdown, the fuel filter cover is unscrewed to remove the strainer. If dirt has simply accumulated on it, washing with gasoline or blowing will help.
With visible damage to the strainer, it is imperative to install a new one. There may also be damage on the fuel supply pipe (during repair, check this element).
The carburetor starter in most cases does not function due to blockages. Use acetone or the same gasoline for flushing.
Blowing off carburetor parts with a blockage of compressed air is an acceptable and convenient repair practice.
The device of the carburetor lawn mowers
The basis of the carburetor of the lawn mowers is an aluminum case. It has a diffuser (hole with internal contours). Air is blown through this hole. The oxygen (air) flow rate depends on the cross-section (passage opening) of the diffuser.
The diffuser is equipped with fuel channels. Of these, fuel is drawn in using an air stream.
Outside the carburetor is installed:
- fuel pump;
- jet system;
- fuel / air mixture control system;
The principle of the carburetor lawn mowers
The throttle valve determines the amount of air for supply, and engine power directly depends on this.
Fuel is sucked into the carburetor system by a pump (its membrane). Then it passes through the fitting in the carburetor. Further, the fluid moves through the inlet and outlet valves of the pump. Filtered by mesh. The needle valve moves into the membrane chamber.
Phased operation of the device:
- Air supply to the tube with an air baffle (damper). The partition controls the intensity of the air flow.
- The fuel supply system must be narrowed by a diffuser to increase the flow rate.
- Gasoline through the float chamber and nozzle tube with narrowing. A camera with a float adjusts the temporary volume of gasoline. In the float chamber, the pressure level is neutral, and in the tube with narrowing is already low. Due to the pressure drop, fuel enters through the nozzle.
- The acceleration of the air flow contributes to the transfer of fuel (gasoline) and its atomization. As a result, an air-fuel mixture of the necessary proportion or density is formed.
- The air-fuel mixture enters the engine cylinder through the fuel pipe.