Do-it-yourself carburetor adjustment for petrol cutters

Petrol cutters, 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 carburetors, 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 carburetor is regulated.

The main problems and malfunctions of the carburetor.

Mesh filter. There are often only two problems with this element:

1. Blockage.
2. Breaking.

In order to find out the cause of the breakdown, the fuel filter cap is unscrewed to remove the strainer. If dirt just 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 clogged carburetor parts is an acceptable and convenient repair practice.

The throttle body, the places where the carburetor parts are connected, the inlet or outlet pipe - all of these parts are subject to depressurization. You can check for sure in a primitive way - smear the problem area with soapy foam.

Carburetor device gas cutters

Carburetor base petrol cutters - aluminium case. It contains a diffuser (hole with inner contours). Air is blown through this hole. The oxygen (air) supply rate 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:

1. Air supply to a tube with an air baffle (damper). The baffle regulates the intensity of the air flow.
2. The fuel supply system is necessarily narrowed by a diffuser to increase the flow rate.
3. 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.
4. 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.
5. The air / fuel mixture enters the engine cylinder through the fuel pipe.

The level of air density in the system depends on the area of ​​the open air damper. The wider the throttle is open, the greater the fuel consumption and power.

Simply put, adjusting the carburetor on a petrol cutter is creating an optimal fuel mixture due to the correct air supply.

How to adjust the carburetor on a petrol cutter

Before adjusting, the filters must be thoroughly cleaned according to the maintenance instructions in the instructions.

Further adjustment of the carburetor of the petrol cutter with your own hands is carried out with the adjusting screws. There are three of them:

• right;
• left;
• lower.

Right (L) - adjustment of the fuel mixture for low rpm.

You need to find the maximum idle speed. To do this, slowly unscrew the screw (L) to the right and left.

To adjust, turn the screw a quarter of a turn always counterclockwise.

Lower (T) - is responsible for adjusting the engine at idle speed.

• clockwise - increase;
• counterclockwise - decrease.

For the correct adjustment of the idle speed, it is characteristic:

• stable operation of a cold engine;
• not overestimated speed of a hot engine;
• a large reserve of turns for the trimmer head;
• stable operation of the engine when changing position (sharp lifting or lowering of the knife).

Left (H) - regulation of the mixture at high speeds. (The screw is adjusted last).

The left screw (H) determines the general adjustment of maximum speed, engine power, temperature and gasoline consumption.

Setting up the carburetor of the brushcutter with the last screw is done as follows:

1. Open the throttle to full, while at the same time give full throttle. Turn the screw clockwise until the speed drops (in this case, orientate by ear).
2. Turn the screw counterclockwise as slowly as possible until the engine runs roughly.
3. Then turn back quite a bit, barely hearing a stable, even operation.
4. For a more visual use of skills, it is more convenient to consider the work of an experienced user:

Interestingly, 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 only by the speed and stability of the engine.

Correct adjustment of the carburetor with your own hands in this case is the combustion of the fuel mixture without residue, the color of the candle should be light brown.

Adjusting the carburetor brushcutters in practice - video