The content of the article:
Petrol, as well as the whole gasoline tools for the garden, is not difficult to maintain machinery. Repair, customize yourself can and should. For example, the adjustment of the carburetor of the gasoline pump by one's own hands is a matter of five minutes.
The carburetor from the gasoline-powered machine is a knot in the power system. In it, as well as any carburettors, there is a process of mixing air and fuel (gasoline) for further supply to the engine cylinders.
In this process, the main thing is the correct proportion of fuel and air, for which the carburettor is regulated.
The main problems and malfunctions of the carburetor.
The mesh filter. There are only two problems with this element:
In order to find out the cause of the failure, the fuel filter cover is unscrewed to remove the strainer. If it simply accumulates dirt, then flushing in gasoline or blowing will help.
If there is visible damage on the mesh filter, it is necessary to put a new one. Also, there may be damage to the fuel connection (in the repair practice of checking this element).
The carburettor starter in most cases does not function due to blockages. Use acetone or the same gasoline for washing.
Purging the carburettor parts with compressed air is an acceptable and convenient repair practice.
The throttle body, the carburetor fittings, the inlet or outlet piping - all of the listed parts are susceptible to depressurization. To check for certain it is possible in the primitive way - a problem site to smear with soap foam.
Device of carburetor gasoline
The basis of the carburetor is a petrol tank - aluminum body. There is a diffuser in it (an opening with internal contours). Through this hole, air is pumped. The speed of oxygen (air) supply depends on the cross-section (passage opening) of the diffuser.
The diffuser is equipped with fuel channels. From them, the fuel is drawn by means of a stream of air.
Outside the carburetor install:
- the fuel pump;
- system of jets;
- system for adjusting the fuel / air mixture;
Principle of carburetor work
The throttle plate determines the amount of air to feed, and the engine power directly depends on this.
In the carburettor system fuel is sucked by the pump (its membrane). Then passes through the choke in the carburetor. The liquid then moves through the inlet and outlet valves of the pump. Filtered grid. The needle valve moves into the membrane chamber.
Step-by-step operation of the device:
- Air supply to the tube with an air partition (flap). The partition 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 jet tube with constriction. A chamber with a float regulates 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 differential pressure, the fuel penetrates through the jet.
- Acceleration of the air flow facilitates the transfer of fuel (gasoline) and its spraying. As a result, an air-fuel mixture of the required proportion or density is formed.
- The air-fuel mixture penetrates into the engine cylinder through the fuel tube.
The level of air density in the system depends on the area of the open air damper. The wider the damper is open, the greater the fuel consumption and power.
Simply put, adjusting the carburetor on the gasoline pump - creating the optimal fuel mixture due to the correct air supply.
How to adjust the carburetor on a petrol pump
Before adjustment, the filters must be thoroughly cleaned according to the maintenance instructions in the manual.
Further tuning of the carburetor of the gasoline pump with its own hands is done by adjusting screws. There are only three:
Right (L)- adjustment of the fuel mixture for low revs.
You need to find the maximum speed at idle. To do this, unscrew the screw (L) slowly to the right and to the left.
For adjustment turn the screw a quarter of a turn necessarily counterclockwise.
Lower (T)- It is responsible for the adjustment of the engine at idle.
- clockwise - increase;
- anti-clockwise - decrease.
For correct adjustment of the idle speed is typical:
- stable operation of the cold engine;
- not excessive speed of the hot engine;
- for the trimmer head a large reserve of turns;
- stable operation of the engine when changing position (sharp rise or lowering of the knife).
The left (H)- adjustment of the mixture at high revs. (Adjust the screw last).
The total adjustment of the maximum rpm, engine power, temperature and gasoline consumption depends on the left screw (H).
The carburetor tuning for the last screw is as follows:
- Open the throttle to full, while giving full throttle. Turn the screw clockwise until the revolutions drop (in this case, orient to the ear).
- Turn the screw as slowly as possible counter-clockwise to uneven engine operation.
- Then turn back quite a bit, barely hearing the stable, smooth work.
- For a more visual application of skills it is more convenient to consider the work of an experienced user:
It is interesting that from the point of view of the author of the video, the setting (its correctness) is determined by the color of the candle, and not just by speed and stability of the engine.
Correct adjustment of the carburetor with your own hands in this case - combustion of the fuel mixture without residue, the color of the candle should be light brown.