How to adjust the carburetor on the trimmer

Fuel pump problems

A common malfunction that “pursues” the fuel pump is the deformation of the pump membrane. For this reason, it does not fit properly and the pump passages are not sealed.

adjust, carburetor, trimmer

The reasons for membrane deformation can be the following:

  • continuous operation of the grass trimmer;
  • use of unsuitable fuel;
  • ingress of gases into the impulse channel.

As a result, diaphragm damage reduces pump performance and, as a result:

  • depletion of the combustible mixture occurs;
  • it is difficult to start the engine;
  • there are interruptions in the operation of the motor;
  • the piston is damaged.

Also, the above-described consequences for the engine can cause clogging of the pump cavity on the impulse side. In this case, dirt enters the membrane through the impulse channel.

To remove the blockage, you will have to disassemble the carburetor and clean the membrane.

Intake needle wear

The inlet needle fails, as a rule, due to the presence of abrasive particles in the fuel fluid.

  • the tightness of the inlet needle seat is disrupted;
  • there is a leakage of a combustible mixture;
  • there are malfunctions in the engine operation associated with re-enrichment of the fuel mixture.

Also, the inlet needle may just jam.

A jammed inlet needle can cause dirt in the fuel or a long idle period.

How to properly adjust the grass trimmer carburetor

On trimmers, in addition to electric motors, gasoline internal combustion engines are installed. This mechanism requires special attention to itself, since if it is incorrectly configured, it will either refuse to work, or will work intermittently and loss of power. Basically, engine tuning is about adjusting the fuel flow, and this is done using the grass trimmer carburetor.

Clogged control cavity

If dirt accumulates in the control cavity, then the inlet needle cannot tightly close the hole and a lot of fuel pours into the chamber.

This causes over-enrichment of the fuel and the engine starts to malfunction. It is necessary to disassemble the carburetor and clean the cavity of the control membrane.

Adjustment lever defective

This breakage occurs when the contact surface of the lever wears out.

The abrasion of the contact surface occurs due to the presence of abrasive particles in the gasoline or due to strong vibration of the engine during operation. This defect in the adjusting lever causes problems with the intake, as well as improper idling of the engine.

When to adjust

Carburetor adjustment is necessary in the following cases:

  • the new engine was run-in (4-5 liters of fuel mixture was used);
  • the composition of the fuel has changed (brand of oil and gasoline);
  • the weather has changed (it became hot, cold);
  • the rarefaction of air has changed (applies to mountainous regions);
  • after long-term storage;
  • increased load on the engine (after changing tools, etc.);
  • due to vibration, the adjustment screws spontaneously unscrewed;
  • fuel consumption has increased, the carburetor overflows fuel;
  • carbon deposits quickly appear on the spark plug electrodes (while the fuel mixture is prepared correctly);
  • the engine starts and immediately stalls or gains momentum poorly;
  • gasoline does not enter the cylinder;
  • large amount of exhaust gases.

Intake Adjustment Lever Problem

This problem can occur if the adjusting arm is not properly installed or if it is bent before installing. As a result, the contact surface takes the wrong position, which disrupts the additional fuel supply.

Grass trimmer carburetor. How to properly adjust the grass trimmer carburetor.

On trimmers, in addition to electric motors, gasoline internal combustion engines are installed. This mechanism requires special attention to itself, since if it is incorrectly configured, it will either refuse to work, or will work intermittently and loss of power. Basically, engine tuning is about adjusting the fuel flow, and this is done using the grass trimmer carburetor.

The standard design of any gasoline grass trimmer necessarily includes a fuel system, the basis of which is the action of a regular carburetor. Its structure and initial principle of operation are almost the same for all brushcutters, regardless of their design features and purpose.

The brushcutter carburetor consists of an all-metal aluminum body that protects the internal components of the unit from moisture, fine 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 discharge becomes maximum.

HOW TO ADJUST The Carburetor on Weedeater XT260 Grass Trimmer

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 the brushcutter 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 power rating of the grass trimmer. Another function of the damper is to facilitate cold starting of the engine. If the mower is starting up for the first time 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 grass trimmer carburetor 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 engine cylinder creates reciprocating movements, 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 passes through the integrated inlet and outlet 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 stock trimmer carburetor valve is connected to the diaphragm using a lever. Below the built-in membrane there 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.

Correct Way To Adjust Or Tune The Carburetor On A Weedeater / Grass Trimmer

When is the carburetor setting of the household grass trimmer required? Adjust the built-in grass trimmer carburetor when:

  • running in a new engine, during which 4 to 5 liters of fuel mixture were used;
  • sudden changes in the weather;
  • changes in the air pressure. for example, when the mower is often used in mountainous areas;
  • long-term simple grass trimmer;
  • intensive growth of loads on the power unit of brushcutters;
  • 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;
  • pouring 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 the standard spark plug for the grass trimmer;
  • starting the engine and its arbitrary shutdown or slow set of revolutions;
  • lack of fuel flow into the cylinder of the power unit;
  • increase in the volume of emitted waste gases.

ADJUSTING THE CARB ON THE CHEAPEST STRING TRIMMER, HEDGE TRIMMER AND POLE SAW ON EBAY!!!!!!

The lack of timely adjustment of the carburetor threatens serious damage to the grass trimmer, up to the complete failure of its factory engine.

Do-it-yourself lawn mower carburetor adjustment. Periodic adjustment of the grass trimmer carburetor must be performed with a serviced and fully functional 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 brushcutter design.

When adjusting the carburetor, the mower’s engine must be running under a certain load. It is best to install a cord of the appropriate diameter or cutting blades on the grass trimmer.

After installing the cutters, the operator should start the engine of the grass trimmer and let it run 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 revs. 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. As soon as the maximum speed is reached, the screw will need to be turned 1/2 turn to the left;
  • The screw “T” or “LA” 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 increase accordingly;
  • The “H” regulator on the left is responsible for enriching the fuel mixture with air when the internal combustion engine of the grass trimmer is operating 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.

Common carburetor malfunctions. Failure of the grass trimmer carburetor is caused by the use of poor quality gasoline, a damaged air filter, and accumulation of dirt in the chamber of this unit. Most often, it is quite possible to repair the carburetor with your own hands. Listed below are typical brushcutter carburetor malfunctions.

Fuel pump problems. A common malfunction that “pursues” the fuel pump is the deformation of the pump membrane. For this reason, it does not fit properly and the pump passages are not sealed.

The reasons for membrane deformation can be the following:

  • continuous operation of the grass trimmer;
  • use of unsuitable fuel;
  • ingress of gases into the impulse channel.

As a result, diaphragm damage reduces pump performance and, as a result:

  • depletion of the combustible mixture occurs;
  • it is difficult to start the engine;
  • there are interruptions in the operation of the motor;
  • the piston is damaged.

Also, the above-described consequences for the engine can cause clogging of the pump cavity on the impulse side. In this case, dirt enters the membrane through the impulse channel.

To remove the blockage, you will have to disassemble the carburetor and clean the membrane.

Strainer clogged The strainer can become clogged if contaminated fuel enters through a defective fuel hose or pickup head. In the photo below you can see what a clean filter looks like and a dirty one (parts are separated by a line).

Correcting the malfunction will require thorough cleaning and rinsing of the strainer. It is also recommended to blow compressed air through all holes in the grass trimmer carburetor housing.

The adjusting lever is defective This breakdown occurs when the contact surface of the lever wears out.

The abrasion of the contact surface occurs due to the presence of abrasive particles in the gasoline or due to strong vibration of the engine during operation. This defect in the adjusting lever causes problems with the intake, as well as improper idling of the engine.

Inlet needle wear The inlet needle is damaged, usually due to the presence of abrasive particles in the fuel fluid.

  • the tightness of the inlet needle seat is disrupted;
  • there is a leakage of a combustible mixture;
  • there are malfunctions in the engine operation associated with re-enrichment of the fuel mixture.

Also, the inlet needle may just jam.

A jammed inlet needle can cause dirt in the fuel or a long idle period.

Clogged control cavity If dirt accumulates in the control cavity, the inlet needle cannot close the hole tightly and a lot of fuel pours into the chamber.

This causes over-enrichment of the fuel and the engine starts to malfunction. It is necessary to disassemble the carburetor and clean the cavity of the control membrane.

Deformation of the control diaphragm The diaphragm can be deformed during prolonged operation of the unit and when using aggressive fuels.

Failure of normal adjustment due to a defect leads to:

  • damage to the piston;
  • difficulties when starting up;
  • depletion of fuel;
  • improper engine operation.

Inlet Adjustment Lever Problem This problem can occur if the adjustment lever is not installed correctly or if it is bent before installing. As a result, the contact surface takes the wrong position, which disrupts the additional fuel supply.

Flap wear The throttle and choke valves are mainly worn out by the presence of abrasive particles in the air. Defective dampers look like they have been sandblasted.

As a result of valve wear, engine performance decreases, malfunctions appear in its operation, piston rings, piston and cylinder coating wear out.

Throttle and choke shaft wear The air and choke shaft can wear for the following reasons:

  • insufficient and improper maintenance of the air filter;
  • the air filter is damaged;
  • the air filter is not suitable for this unit.

Due to the ingress of poorly cleaned air, the shaft wears out and can break. Broken shaft parts can enter the combustion chamber or crankcase and cause serious damage to the entire piston system.

To eliminate problems with air purification, it is necessary to replace the defective filter or flush the existing (serviceable) one. The filter must be washed in soapy water and dried.

How to make the correct adjustment Before you start adjusting the carburetor of the grass trimmer, do the following:

  • flush the engine;
  • replace or clean the spark plug;
  • change to a new one or clean the air filter (it is recommended to wash it in warm, soapy water, wring it out and let it dry well).

It is also necessary to install a cord of a suitable diameter in the trimmer coil or install knives. this is done so that during the tuning process the engine has at least some kind of load. After installing the cutting tool and starting the gasoline engine, let it warm up for 10 minutes.

If at idle speed of the engine you notice that the cutting tool rotates, then it is necessary to reduce the engine speed. This is done using the lower idle speed control, often marked with the letter “T”. But, for example, on a STIHL trimmer, this screw may be marked “LA”.

So, turn the idle speed control to the left until the trimmer head comes to a complete stop.

To adjust the carburetor, 3 regulators (screws) are used.

  • The right L regulator adjusts the fuel mixture enrichment level at low revs. It needs to be regulated first. Achieve maximum idle speed. This is done with the L knob by turning it left and right. After finding the point of maximum speed, return the regulator half a turn to the left (counter-clockwise).
  • The lower T (LA) adjuster is used to adjust the idle speed. Turning it to the left, the engine speed will begin to decrease, and when turning the regulator to the right, the engine speed will increase.
  • The left regulator H is responsible for enriching the combustible mixture at high speeds. The enrichment setting completes the carburetor setting. Also, using this regulator, you can adjust the maximum speed, fuel consumption and engine power.

Important! If the engine is allowed to run at full speed for more than 10 seconds, then it may fail.

To eliminate this nuisance, adjustment will be required. With the engine running, give full throttle, then turn the regulator “H” to the right until the speed starts to decrease. After that, the “H” regulator must be slowly scrolled to the left until you hear the uneven operation of the engine. Then you should turn the knob “H” to the right until you hear the smooth operation of the motor.

After carrying out the above steps, the carburetor setting can be considered complete. After correct adjustment, the engine should confidently pick up speed, a little quarter at maximum speed, and when idling, the cutting tool should not turn. This manual is suitable for adjusting carburettors on Huter, Patriot and other petrol cutters.

There are also carburetors without a screw, which is responsible for enriching the fuel mixture at low speeds. That is, they have only 2 adjusting screws: an idle speed regulator and a fuel mixture quality regulator at high speeds.

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