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Chainsaw carburetor adjustment: we analyze all the technical nuances of the work

Chainsaw carburetor adjustment: we analyze all the technical nuances of the work


Summer cottage construction and repairs are not complete without the use of a chainsaw, as well as garden maintenance. Due to a malfunction of the tool, all work can get up, so it is so important to be able to disassemble it yourself, find problems and fix them. With enough experience and dexterity, it is even possible to adjust the carburetor of a chainsaw - a complicated procedure, or rather, jewelry. How to carry out the adjustment procedures, we suggest you disassemble today.

Chainsaw carburetor device

Not a single repair event is complete without knowledge of the basics of the mechanism. By understanding the constituent elements and the principle of operation, it is easier to determine the cause of the breakdown.

Any malfunction in the carburetor threatens to stop the engine

The carburetor is one of the main functional parts of the engine, which serves to prepare and supply a fuel mixture consisting of certain proportions of fuel and air. As soon as the proportions are violated, the engine starts to junk, or even stops working altogether.

You can achieve the correct operation of the carburetor by examining its filling:

  • Cross-flap tube for air flow regulation.
  • Diffuser - Constriction to increase the air flow rate, located near the fuel inlet.
  • Sprayer from which fuel comes (fuel needle in the diagram).
  • A float chamber that regulates the fuel level at the entrance to the channel.

This is how it looks in the diagram:

The diagram shows the interaction of fuel and air flow

How it works: A jet of air in the diffuser atomizes the fuel, creating a mixture that enters the cylinder. The greater the amount of fuel supplied, the higher the engine speed. Different carburettors work in the same way.

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When is adjustment necessary at all?

Specifically, adjusting the carburetor of a chainsaw is required in rare cases, more often problems arise related to the flow of fuel or wear of parts. But sometimes the symptoms indicate that it is necessary to adjust the mechanism. Here are some signs:

  • After the engine starts, it immediately stalls. Alternatively, it will not start at all. The reason lies in the excess air and fuel shortage.
  • Increased fuel consumption and, as a result, a large amount of exhaust gases. This is due to the reverse process - oversaturation of the mixture with fuel.

The reasons for the adjustment failure can be mechanical:

  • Strong vibration damages the protective cap, causing all three bolts to lose their position.
  • Due to wear on the piston part of the engine. In this case, adjusting the carburetor of the chainsaw will only help out for a while, it is better to replace the worn part.
  • Due to clogging caused by low-quality fuel, scale or damage to the filter. The carburetor requires complete disassembly, flushing and adjustment.

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If the chainsaw suddenly stops working, you need to disassemble it to find out the reasons

Step-by-step instructions for disassembly

The carburetor device of models of different brands is almost the same, so take the Partner chainsaw as an example. We carefully remove each element and put it in order, so that later it would be easier to assemble.

Chainsaw carburetors from different manufacturers, if they differ, it does not matter

The top cover is removed by loosening three screws. Following it is foam rubber, an integral part of the air filter.

The arrows indicate the bolts that must be unscrewed to remove the cover

Then we remove the fuel hose, followed by the drive rod.

The upper arrow points to the fuel hose, the lower arrow points to the drive rod

Next, remove the tip of the cable.

The arrow shows the end of the cable to be removed.

On the left from the fitting, we pull together the gasoline hose.

We also carefully remove the gasoline hose indicated by the arrow

We finally disconnect the carburetor, it is ready for adjustment. Its mechanism is rather complicated, therefore, if further disassembly of the carburetor is required, the elements should be removed very carefully - they are small, so they can be lost.

The carburetor consists of many small parts, which should be laid out in order during disassembly.

Features of setting and adjustment

To find out how to adjust the carburetor on a chainsaw, you need to learn to distinguish between three screws (some models have only one).

The L and H screws are similar only in appearance, in fact they are different

Each screw has its own letter designation:

  • L is for setting low rpm;
  • H is needed to adjust the upper speed;
  • T is needed to adjust the idle speed (for models with one screw, only it is present).

The factory setting is optimal, and the screws are used to adjust the engine operation in special situations (work associated with different climatic conditions).

The diagram shows the outputs of the carburetor adjustment screws with the lid closed

A special tool is used to set up the chainsaw.

Adjustment is carried out only with screws L and H. To increase the speed, turn them clockwise. To decrease - counterclockwise. The sequence of using screws: L - H - T.

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If you have any doubts about the adjustment, it is better to contact a specialist, since an incorrect setting can damage the engine.

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When carburetor adjustment is required

The new chainsaw is adjusted to the recommended mix. All you need to do is fine-tuning with three screws; you don't need to disassemble the carburetor. The purpose of the adjusting screws:

"L" regulates fuel delivery at low rpm
"H" is needed to regulate the maximum fuel supply
"T" idle speed regulator.

Since the saw carburetor is adjusted by ear with the engine running, safety precautions must be observed. The saw should be positioned securely with the cutters pointed in a safe direction for those present.

Before starting the manipulation, it is necessary to mark the initial position of the screws with paint or felt-tip pen. The exact values ​​for setting the carburetor of the chainsaw for each model are in the instruction manual.

However, more often, a carburetor tincture is required after eliminating a tool malfunction. The reasons may be:

violation of the protective cap and imbalance of the screws
engine piston wear requiring a different mixture to work
unsatisfactory operation of the carburetor itself.

How to adjust the carburetor on a particular model chainsaw? Perform operations sequentially, guided by the instructions. Here is the algorithm, the general sequence of actions.

There are two stages of adjustment:

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basic, with the engine off
thin - on a warm engine, idling.

The basic setting is only for the low and high speed fuel screws. Smoothly, without haste, you should completely close the flaps to the stop. Also slowly open both screws counterclockwise by 1.5 turns. Then start the engine and warm it up for 10 minutes.

How to adjust the carburetor on a chainsaw with the engine running:

adjust idle speed with screw "T", turning counterclockwise until stable operation of the motor at idle speed
check the speed of the set of revolutions, with slow unwinding, turn the screw L an additional 1/8 turn
set the highest rotation speed according to the tachometer with the screw H
check the operation of the carburetor at idle speed completely.


Purpose, design and principle of operation of the carburetor.

The carburetor is needed to prepare the air-fuel mixture to power the engine. If the proportions in this mixture are not correct, the motor will malfunction. If the proportion is not observed in the direction of increasing the amount of fuel, the mixture is called oversaturated, if, on the contrary, there is little fuel, it is called lean. Both of them do not affect the operation of the engine in the best way.

In different models of chainsaws, carburetors differ in design, but they are similar in principle of operation. The air stream moves at high speed through the air duct. A damper blocking the channel allows you to change the speed of the air stream. The fuel is fed through the nozzle into the channel, where it mixes with the incoming air, forming an air-fuel mixture. The resulting mixture enters the engine.

The pressure in the float chamber, where the fuel is located before mixing, is practically equal to atmospheric pressure. But a vacuum is created in the air channel, due to which the fuel is drawn into the air stream. The more the damper is opened, the faster the air moves, and the amount of fuel also increases - the engine speed increases. So, in a simplified way, you can imagine the principle of operation of the carburetor.

Chainsaw carburetor adjustment is required for efficient, smooth operation of the tool, getting maximum output and at the same time economical fuel consumption. Before adjusting, the fuel and air filters must be checked - they must be clean. On most chainsaws, adjustment is carried out with three screws: idle, high speed, low speed. The following signs indicate the correct setting of the carburetor:

  1. The chain does not move when idling.
  2. The engine accelerates smoothly and quickly.
  3. The sound of the engine running is smooth, similar to the sound of a four-stroke engine.

Adjusting the carburetor should be treated with all possible care, because errors in the settings can lead to very serious consequences, up to the occurrence of engine malfunction. If you are not completely confident in your abilities, you need to contact the service center.


Instruction for Chinese

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

Chinese Chainsaw Model

Adjustment procedure:

  1. Activities start in idle mode... With the help of the adjusting screws, you need to achieve a systematic set of revolutions by the engine, so you should first let it run at low speeds. The deviation from the norm is the movement of the chain along the tire. In this case, you need to adjust the extreme screws to the optimal position so that the chain remains stationary.
  2. Transition to medium speed rpm is in progress... Sometimes the engine will smoke. 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 until the level is reached when, when the throttle is pressed, the engine smoothly picks up speed, no sudden jerks or interruptions are heard.

  • The device motor is being checked... The chainsaw is moved to minimum speed, and then the lever is rapidly pressed. At maximum pressure, it is held for 3 seconds. If there is an abnormality in the operation of the engine, gradually loosen the screw until the optimum position is reached.
  • The chainsaw should run for several hours under real conditions.... It is necessary to engage in sawing wood, and then inspect all the elements involved in this event. If there are deviations, they must be corrected using adjusting devices. When all defects have been eliminated and optimal settings have been established for supplying a properly concentrated fuel, the process of setting up the device can be considered complete.