Carburetor Replacement In Chinese Chainsaw

For self-tuning of the carburetor, you need to familiarize yourself with its device and remember the order of the work that is carried out to adjust the parts responsible for the proper functioning of the constituent elements of the device and the parts adjacent to it. It is necessary to carefully handle objects to adjust the chainsaw system, as well as determine the compliance of the set parameters with the maximum allowable values.

About carburetor design

The carburetor is used to mix the combustible mixture with air in compliance with predetermined proportions. If the exact doses are not respected, the health of the engine is at risk. When a large amount of air enters during mixing of the components, and there is not enough fuel, such a mixture is considered “poor.”

It should not be allowed and oversaturation, since with a large amount of fuel compared to air, malfunctions or engine wear are also possible. Adjustment of the carburetor is necessary not only before initial use, but also when any deviations in its operation are detected. Before you start working with a chainsaw, do not forget to run it in.

The carburetor design contains a standard set of elements, but may vary slightly depending on the manufacturer. Components:

  1. The foundation. This is a special tube that visually resembles an aerodynamic design. Air passes through it. In the transverse direction, a shutter is located in the middle of the pipe. Her position can be changed. The more it is pushed into the passage, the less air enters the engine.
  2. Diffuser. This is the lent out part of the tube. With its help, the air supply rate increases in the segment where the fuel comes from.
  3. Channels to supply fuel. The fuel mixture is contained in the float chamber, then passes into the nozzle, from which flows into the spray.
  4. Float chamber. It is a separate structural element that resembles the shape of a tank. Designed to constantly maintain an optimal level of fuel fluid before entering the channel from where air comes.

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What you need to have to configure and adjust your chainsaw yourself

Each carburetor owner must have the necessary tools to adjust this system. There are three adjusting screws that are located on the device. They have their own markings:

  • L. screw for low speed correction.
  • H. screw for adjusting high revs.
  • T. regulates idling, in most cases it is used for experiments.

Before adjusting the carburetor, you need to prepare the device:

  1. The engine warms up, that is, it starts about 10 minutes before repair, and turns off when work starts (see how to start a chainsaw).
  2. The air filter is checked and flushed.
  3. The chain is stopped by turning the T screw all the way (see chain oil).

To carry out safe repairs, you need to prepare a flat surface where you can neatly position the device and unscrew the chain in the opposite direction. Need a tachometer. It determines the presence of a malfunction in the carburetor. When turning the screws, the sound should be perfect and absolutely even. If screeching notes are noticed, then the mixture is oversaturated.

How to properly adjust the factory saw

Carburettor adjustment is divided into two main stages. The first is called basic. It is made with the engine turned on. The second is performed when the engine is warm.

To carry out the carb adjustment procedure successfully, you need to familiarize yourself with the instruction manual specific model to identify additional features of the device settings.

First stage

The adjusting screws for the highest and lowest revolutions should be carried out clockwise until the highest resistance is encountered. When the screws reach the stop, you need to translate them in the opposite direction and leave when passing 1.5 turns.

carburetor replacement on a Chinese chainsaw

Main stage

The engine starts at medium speed and it warms up like this for about 10 minutes. The idle adjustment screw should be clockwise. It is released only when the engine comes into stable operation. It must be ensured that the chain does not move during this process.

Video: Carburetor Replacement In Chinese Chainsaw

In idle mode, the engine may stall (the reason is here). In this case, immediately adjust the adjusting screw clockwise to the stop. Sometimes the chain begins to move. In this case, turn the adjusting screw in the opposite direction.

Acceleration Test

You need to do a little research. The acceleration of the device is initiated. It is necessary to evaluate the serviceability of the engine during maximum revolutions. When the engine is functioning properly, it means when you click on the accelerator, the speed increases rapidly to 15,000 rpm.

If this does not happen or the speed increase is too slow, you must use the screw marked with the letter L. It turns counterclockwise. It is necessary to observe moderate movements, since the turn cannot be more than 1/8 of the full circle.

How to adjust the maximum number of revolutions

To limit this figure, you need to use a screw marked H. To increase the number of revolutions, turn it clockwise, and to decrease it in the opposite direction. The maximum frequency must not exceed 15,000 rpm.

If you make this figure more, the engine of the device will run to wear, which will lead to problems in the ignition system. When rotating this screw, the ignition processes of the device must be taken into account. If the slightest glitches appear, then the maximum speed value must be reduced.

Final idle check

Before this procedure, it is necessary to perform a full adjustment of the components of the carburetor when operating at maximum speed. Next, you should check the operation of the device in idle cold mode. When the correct parameters are reached during adjustment, you can see the exact compliance of the carburetor design with the following criteria:

  1. When the idle cold mode is connected, the circuit does not move.
  • When even pressing the accelerator a little, the engine accelerates at an accelerated pace. With a gradual increase in pressure, you can notice that the engine speed is proportionally increasing, reaching the maximum allowable values.
  • When the engine is running, you can compare its sound with a four-stroke device.
  • If violations are noted in the given parameters or the device was not fully adjusted, you need to perform the main setup step again. Sometimes actions are performed incorrectly. In this case, the device may fail due to the loss of the correct node settings. In this case, you will have to contact a specialist.

    Dismantling the carburetor if necessary to check or repair the components

    The device of different models of carburetors is almost the same, therefore, when working with them, you can use the standard scheme. All items must be removed carefully and then lay out in the order below, so that you can successfully arrange the objects in place at the end of the repair work.

    1. The top cover is removed. To do this, unscrew the 3 bolts holding it in a circle.
    2. Foam is also removed, as it is the upper part of the filter that conducts air.
    3. The fuel hose is removed.
    4. The drive rod is displayed immediately on it.
    5. The cable tip is disconnected.
    6. The gas hose can be completely removed by steadily pulling it off the fitting.

    To finally prepare the carburetor for a major overhaul or replacement of the smallest parts, you need to carefully disconnect it from the main system. Sometimes it requires further disassembly. Unscrew the components carefully and fold the fasteners in groups, as these small parts are easily lost.

    How to properly configure a Chinese-made saw. adjusting instruction

    To correctly configure the carburetor of a Chinese chainsaw, you must first remember the factory settings of the device, then turn on the engine. In the future, you will have to leave it to work for several hours to accurately set your own parameters. Sometimes work is performed once after a ten-minute operation of the engine, but many Chinese-made models require special handling.

    Adjustment Procedure:

    1. Events start at idle. Using the adjusting screws, you need to achieve a systematic set of revolutions by the engine, so you should first let it work at low speeds. A deviation from the norm is the movement of the chain along the bus. In this case, it is necessary to adjust the extreme position of the extreme screws so that the chain remains stationary.
    2. Switching to medium speed revs. Sometimes the engine smokes at the same time. This defect can be eliminated by tightening the screw to supply a leaner fuel mixture.

    In this case, the smoke will disappear, but the engine speed will increase. It is necessary to adjust the settings to the level where, when you press the throttle, the engine gains speed, sharp jerks or interruptions are not heard.

  • Device engine check in progress. The chainsaw is transferred to the minimum speed, and then a rapid pressing of the lever is carried out. With maximum pressure, it is held for 3 seconds. If there is a malfunction in the engine, you need to gradually loosen the screw until the optimum position is reached.
  • Chainsaw should work for several hours in real conditions. It is necessary to engage in sawing wood, and then perform an inspection of all the elements involved in this event. If there are deviations, they need to be corrected using adjusting devices. When all defects have been eliminated and optimal settings have been set for the supply of correctly concentrated fuel, the process of setting up the device can be considered completed.
  • Before buying, we recommend that you familiarize yourself with the rating of chainsaws for reliability and quality.
    Look at the video clearly:


    In order for the chainsaw to work properly, it is necessary to carefully carry out work on adjusting the carburetor in exact accordance with their priority. If there are any malfunctions in the operation of the device, you must independently perform its complete disassembly. In most cases, replacement of any parts that have become unusable is required.

    With a constant check of the quality of the carburetor settings and the implementation of timely actions to improve its operation, there are no problems with the chainsaw.

    About which chainsaw to choose. read here.