STIHL fs 55 grass trimmer carburetor setting

Lawn Mower Carburetor Working Principle

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 choke in the carburetor. The fluid then flows through the pump inlet and outlet valves. Filtered by the grid. Moves through the needle valve into the diaphragm chamber.

stihl, grass, trimmer, carburetor
  • 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 penetrates through the nozzle.
  • 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.

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. creating an optimal fuel mixture due to the correct air supply.

Carburetor cannot be adjusted

The fact that the adjustment is too coarse (it is not possible to accurately set the parameters) are to blame for the springs on the adjusting screws. A brushcutter or grass trimmer manufacturer may supply unnecessarily thick and stiff springs. Others can be found either in workshops where similar equipment is repaired, or purchased from any dealer or official representative of the company that produced the motor for your grass trimmer or power scythe.

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Stihl fs55 carburetor adjustment trimmer weedeater gas trimmer tune up

Major problems

Malfunctions of the carburetor of a brushcutter or grass trimmer, despite the relative ease of their elimination, sometimes require a long search by the method of elimination. The main reasons are:

stihl, grass, trimmer, carburetor
  • unsatisfactory quality of gasoline purification;
  • air filter clogging;
  • accumulation of deposits and carbon deposits in the compartments and passages of the carburetor.

Lawn Mower Carburetor Working Principle

The throttle valve determines the amount of air to be supplied, and the power of the motor directly depends on this.

The correctness of the carburetor option is determined by the operation of the engine and by the color of the spark plug. Adjusted

Self-tuning the carburetor on a Chinese trimmer, quickly and easily adjust the carburetor to

Fuel is sucked into the carburetor system by a pump (its membrane). Then it goes through the choke in the carburetor. Then the liquid moves through the inlet and outlet valves of the pump. Filtered by the grid. Moves through the needle valve into the diaphragm chamber.

  • 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 the mixer to accelerate the flow.
  • 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 small. Due to the pressure drop, the fuel seeps through the jet.
  • The acceleration of the air flow assists in the transfer of fuel (gasoline) and its atomization. Ultimately, an air-fuel mixture of the desired proportion or density appears.
  • The air / fuel mixture seeps into 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.

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Simply put, adjusting the carburetor on a petrol cutter. creating a good fuel consistency due to the correct air supply.

Lawn mower device

The device of the STIHL FS 55 lawn mower should be clear to you if you plan to operate the equipment, let alone repair it. The internal combustion engine in this unit is almost the same as in a chainsaw. But the tire is the latter fixed to the motor reducer by a long tubular rod. Inside there is a shaft that transmits torque from the motor to the working tool. This design is suspended from a strap that is thrown over the shoulder. This allows you to hold the tool on the weight, which is fundamentally with the sensitive weight of the chainsaw.

A handle is fixed to the bar of the unit, with the help of it you can move the end of the bar with the working equipment. The STIHL FS 55 lawn mower, the repair summary of which is presented in the article, has a protective shield in the form of a casing on the human side, which eliminates injury during operation. The tool itself is a round drum with thick line coming out of the holes on both sides. Adjusting the carburetor and chainsaw repair of the STIHL lawn mower STIHL fs55 fs 38 carburetor. When the drum spins, the line is pulled by centrifugal force and hits the grass, chopping it.

The STIHL FS 55 lawn mower, the technical properties of which will be presented to your attention below, has a wear-resistant nylon line. Features of the STIHL fs 38 brushcutter, the carburetor adjustment of the STIHL fs 38 lawn mower. It is updated from time to time by unwinding the reel inside the drum.

Damper worn out

The throttle and air damper become unusable due to the ingress of dust, metal particles, etc. with the air flow. Damaged dampers are similar to parts that have been blasted with sand. Due to wear on the dampers, the efficiency of the motor decreases, and breakdowns are detected. Piston and cylinder wear out.

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In some cases, this filter is simply not suitable for your brushcutter or grass trimmer model. In the end, the motor shaft will suffer. its pieces fall into the engine channels, which will cause the piston to be broken.

How to adjust the carburetor on a petrol cutter

The upcoming do-it-yourself lawn mower carburetor setting is done with adjusting screws. There are three of them:

Right (L). Fuel Consistency Adjustment for Low RPM.

stihl, grass, trimmer, carburetor

It is necessary to find the highest idle speed. To do this, slowly unscrew the screw (L) to the right and to the left.

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

Stihl Weedeater Carb Adjust

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

  • clockwise. increase;
  • counterclockwise. decrease.

For the correct adjustment of the idle speed specifically, 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). mixture adjustment at high rpm. (The screw is adjusted last).

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

Adjusting the carburetor of a lawn mower with the last screw is done as follows:

  • Open the throttle to full, at the same time give full throttle. Turn the screw clockwise until the speed drops (in this case, orientate by ear).
  • Turn the screw counterclockwise as slowly as possible until the engine runs unevenly.
  • Then turn back quite a bit, barely hearing a stable, even operation.
  • 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.