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Chainsaw carburetor adjustment. expert tips, instructions

A chainsaw is a technically sophisticated tool that needs to be serviced from time to time. Cleaning, replacing filters and, of course, adjusting the carburetor of the chainsaw will help to serve the entire life set for it. In this article, we will consider the issue of carb settings. How and why it is carried out.

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Situations in which adjustment is necessary

New chainsaws are supplied from the manufacturer with adjusted carburetors. This is called standard adjustment. But for the normal passage of the break-in process, it is necessary to lower the maximum engine speed, to adjust the carburetor. After running in, the chainsaw needs to be fine-tuned to achieve maximum engine efficiency.

Also, a signal for cleaning and adjustment is increased fuel consumption, which negatively affects the operation of the exhaust system. Simply put, the chainsaw begins to smoke very much and the muffler becomes clogged with carbon, which in turn will lead to a decrease in power. With a lack of fuel in the mixture, engine parts are poorly lubricated, and premature wear occurs. Also, a poor-quality mixture can cause the engine to jam due to overheating (this is one of the reasons why the chainsaw does not start).

Adjustment is necessary when the engine does not keep idle, stalls or does not develop full power.

The carburetor must be adjusted with clean air and fuel filters.


Correct adjustment of the carburetor of the chainsaw should be carried out using a special tool. a tachometer. It allows you to most accurately determine the maximum number of engine revolutions and adjust them according to the requirements of the manufacturer. To adjust, you need to have a small slotted screwdriver. For some models of chainsaws, you will need a special adjustment key, without which it is impossible to carry out work.

The key for adjusting some carburetor models is available only in service centers authorized by the manufacturer for the repair of chainsaws. This measure is aimed at reducing damage due to improper settings by inexperienced users and those involved in the repair, without official permission to do so.

Setting up the chainsaw should, if possible, be carried out in official service centers that have a certificate from the manufacturer.

How to adjust the carburetor

The algorithm for setting up the chainsaw is quite simple and consists of the following steps:

  1. Adjustment of the engine for smooth operation at low speeds.
  2. Setting the carburetor to the correct flow of the fuel mixture at maximum speed.
  3. Fine carburetor adjustment for idling.
  4. Checking the chainsaw in all modes.

The carburetor must be adjusted after the engine has run a little and warmed up.

Now we will consider how the correct adjustment of the carburetor of the chainsaw goes in more detail. Almost all carburetor models have three adjusting screws. The screw (T) is responsible for fine tuning in idle mode. Screw (H) setting for maximum speed. The screw (L) controls the formation of the mixture at low speeds. By tightening the screws (L) and (H), the fuel supply and the mixture are leaner, respectively, revolutions increase.

Process description

If the carburetor of the chainsaw is not adjusted, and it is not possible to start the chainsaw, then the setting is started by setting the screws (L) and (H) to the standard setting. This is 1/5 turn of the screws until fully tightened. After which, it is necessary to start the engine, let it run for a bit and warm up. The next step is setting the low speed mode. Optimum engine operation at the “bottom” can be achieved by adjusting the screw (L) and idle speed (T). To do this, first screw (L) is tightened until the maximum engine speed is obtained, then it is released by 1/4, and the screw idle is normalized by screw (T).

After adjusting the work on the "bottoms" is the adjustment of traction and maximum engine speed. To do this, slowly tighten the screw (H) and check the speed using the electronic tachometer.

exceeding the maximum engine speed declared by the manufacturer is unacceptable.

An important step is to check the saw in all operating modes after adjusting it, for this you need to allow the chainsaw to cool, and then start according to the cold tool start algorithm. If the saw starts up normally and is idling smoothly, you need to check how it saws. If during the verification process deficiencies in the power of the chainsaw are found, it is necessary to repeat the adjustment of the screw (H) by unscrewing it and checking the traction in operation.

loss of traction at maximum speeds recommended by the manufacturer is an indicator of CPG wear or poor fuel quality.

Carburetor adjustment for Chinese chainsaw

Carburetors mounted on Chinese-made saws are made similarly to European ones and have the same tuning screws.

The carburetor adjustment of the Chinese chainsaw is carried out according to the algorithm presented above, and differs in that during the initial adjustment of the screws (L) and (H) they must be turned out two turns. Further, the carburetors of the Chinese saw are regulated in the same way as the European ones.


The setting of the carburetor of the saw can be studied in the video below. In this video, the wizard shows how the step-by-step adjustment of a Chinese-made chainsaw is performed without using a tachometer. Carries out after adjustment check in various modes.

Adjusting the carburetor of the chainsaw, although it seems a fairly simple process, but requires a very careful and responsible approach. The article describes the process in sufficient detail, however, if you have never regulated a chainsaw, you should turn to specialists, this will save time, nerves and money.

Chainsaw Carb Adjustment. Tips from Service Masters

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Setting up and adjusting the carburetor of the chainsaw is the most technologically simple task, but you still need to know some important nuances before carrying out this operation at home and with your own hands, otherwise you can only aggravate the situation and damage the proper operation of the engine even more.

Before making any manipulations with the carburetor, it is necessary to exclude possible malfunctions that can affect the operation of the chainsaw (create an imitation of a not working or not configured carburetor:

Fuel filter (hoses):

No mechanical damage to the filter housing, no pollution, good throughput

No mechanical damage to the filter surface, no pollution, good throughput

Malfunctions of the ignition system: a working spark plug “paired” with the ignition module should provide the engine with stable operation.

Serviceable exhaust system:

The outlet of the cylinder, as well as the muffler, should not be clogged with soot. as a result of which the braid will "choke", not develop speed. creating an imitation of a faulty carburetor.

Why did we write about this?

The fact is that when the owner is sure that carburetor adjustment is necessary. in 95% of cases, carburetor adjustment has nothing to do with it.

A very large number of factors can affect the operation of the engine of a chainsaw. from a clogged muffler (does not develop revolutions) to loss of tightness in places of crankshaft oil seals, rubber inlet adapters (the saw itself is gaining momentum and adjustment does not help).

It is logical that the owner of the saw will first think of a carburetor, but this is not so in most cases.

Therefore, before you go into the carburetor settings, read to the end and determine for yourself: is it worth adjusting the carburetor yourself?

Almost all carburetors of modern chainsaws have three tuning screws.

Screw T. idle adjustment

Screw L. low speed adjustment

Screw H. adjustment of high speeds.

Basic screws are provided for screws L and H (for example)

Screw L. 1.5 vol. (fully tighten and unscrew by 1.5 turns)

Screw L. 2.0 vol. (fully tighten and unscrew 2.0 turns)

After that, the idle speed and maximum speed are adjusted for a special device (electronic tachometer)

The L and H jets set the required amount of fuel according to the air flow that is supplied through the gas damper. If you turn them clockwise, the air / fuel ratio is depleted (less fuel), if counterclockwise, the air / fuel ratio is enriched (more fuel). Impoverishment of the mixture — engine revolutions increase; during enrichment — revolutions decrease.

Setting screw L. Turning the nozzle clockwise and counterclockwise. find the maximum engine speed.

After this, turn the nozzle L counterclockwise approximately 1/4 turn.

Screw T. adjusts idle speed.

When tightening the screw, the revolutions increase, when unscrewing (counterclockwise, the revolutions decrease).

The adjustment is simple. screw T is tightened until the chain starts to rotate. Then, slowly, clockwise, screw T is loosened until the chain does not stop. The engine should work stably.

Jet H. adjusts the maximum speed.

Those. if screw H. will be tightly screwed (poor mixture). engine speed will be oversized.

If screw H. will be tightly twisted (rich mixture). “a lot of smoke” will come out of the muffler. clockwise adjustment is necessary.

Precise adjustment of the maximum speed is not possible without an electronic tachometer. It is on it that the maximum revolutions for a particular carburetor, a specific saw are set.

What threatens not the correct adjustment of the maximum speed?

Well, for example, failure of the piston group (thermal seizures):

Some manufacturers of gasoline tools Husqvarna, Homelite, MTD complete their carburetors with jets for a special screwdriver.

This is done to maximize the difficulty of the process of self-adjusting the carburetor by the owner of the saw.

Some will think that the goal is to “weld up” on the sale of screwdrivers for adjustment (they are really expensive), but in reality it is to protect the saw engine from incorrectly set maximum revolutions.

Each saw model has its own characteristics and small "sores" that can create an imitation of an inoperative carburetor, so before you go into the carburetor settings you need to make sure that there are no other malfunctions.

Carburetor adjustment is a complex process that requires experience, knowledge and a special expensive tool, so entrust this process to a specialist of an authorized service center. Believe me, this will cost tens of times less than the cost of the piston group of your saw, which can fail as a result of incorrect adjustment.

how to set up and repair factory models do it yourself

Chainsaw. a tool that is useful in any country house, even for lovers, not to mention professional workers. But, like any other device, a chainsaw needs constant care and prevention. One of the most common procedures is to adjust the carburetor of the chainsaw due to incorrect settings in the past.

The first signs of a carb malfunction

Due to the untimely or unprofessional periodic maintenance of the chainsaw, as well as due to the heavy load, difficulties in its operation may arise from time to time. For professional workers, such breakdowns can reduce their work efficiency and ruin their mood for the whole day.

Carburetor malfunctions, in turn, have specific symptoms. From them, you can immediately determine the cause of the breakdown.

The following signs indicate incorrect carburetor settings:

  1. The tool starts up problematically, after which it immediately stalls.
  2. The chainsaw stalls when you press the gas.
  3. Gasoline is consumed in large quantities, and it still remains in the cylinders and does not burn out until the end, and the exhaust is excessively thick.
  4. The carburettor settings set at the manufacturer’s factory are lost due to improper use or self-adjustment.
  5. Debris has entered the air intake system. Because of this, she failed.
  6. Engine pistons used up. Setting the carburetor in this case only temporarily solves the problem.

In the event that dirt has got into the carburetor, one setting is indispensable. Here you just need to clean it. When the pistons are used up, an overhaul of the engine is required.

But after that, of course, you need to configure the carburetor jets, as well as blowing and cleaning them.

Operating principle

The purpose of the carburetor is to prepare the working mixture for feeding it into the engine cylinders. This mixture is gasoline and air in the proportions necessary for the operation of the engine. If this ratio is violated, the engine will not work clearly. When the mixture has a lot of gasoline, then it is called unprofessional terminology as saturated, and if, on the contrary, it is small, then poor. But in any case, a failure in the proportions of the working mixture will have a bad effect on performance.

Different models of chainsaws may have different designs of carburetors, but by the principle of action they are all identical. Air through a special channel moves at a speed that can be adjusted by closing or opening the damper. Gasoline, in turn, enters the carburetor through the jets and mixes with air there, creating a special mixture that enters the engine.

The pressure in the float compartment of the carburetor, where gas is before mixing, is close to atmospheric. When you open the damper, the air becomes larger, as well as gasoline, due to which the engine speed increases. In this case, a vacuum is created in the air channel and gasoline is drawn into the air stream. This is the principle of the carburetor.

In order for the chainsaw to work smoothly and efficiently, and also without a lot of fuel consumption, its carburetor must be adjusted accordingly. Before such work, you must first check the air and gas filter. If dirt is found on them, they should be replaced.

Chainsaw tuning for most models, as a rule, is carried out with the help of three screws. high and low revs and idle.

The following signs should indicate proper configuration:

  1. The chain should not idle.
  2. The motor runs smoothly.
  3. At the start, there should also be no breaks in the work.

Do-it-yourself carburetor repair of the chainsaw should be done very carefully, because any mistake made can lead to serious consequences, even before the engine breaks down completely. If there is not enough experience, then it is better to seek the help of a specialist.

Husqvarna chainsaw adjustment

During the break-in period of the Husqvarna 142, 240, 236, 137 chainsaw and other similar models, the carburetor settings are set in such a way that the engine speed is 600-700 less than ordinary workers. In the case when it is not possible to adjust the operating frequency by the tachometer, it is not recommended to reset the factory settings with the screw H.

The manufacturer categorically prohibits exceeding independently the working number of revolutions. When, after setting the carburetor, the chain of the chainsaw moves at idle, it is necessary to stop it by turning the screw T counterclockwise.

In order to fine-tune the saw, it must be installed on a flat surface with the tire forward. You also need to warm up the engine for at least 12-15 minutes. First, determine the highest idle frequency. To do this, in the chainsaw screw L must be turned clockwise, and then in the opposite direction. After determining the desired frequency, the same screw rotates counterclockwise from 12 to 25% of its full revolution.

Idling in the models of this manufacturer is configured using a jet with the letter T. The setting is made by turning it clockwise until the chain moves. After that, turn easily counterclockwise until the chain stops moving.

The screw H of the chainsaw is adjusted correctly only when the saw does not make a lot of noise when the gas is pressed to the end, and at the same time it does not weigh down with any load.

In the event that the saw is too noisy during operation and smokes, then this nozzle must be turned from left to right to adjust.

Saws Stihl and Partner

In the Stihl 250, 361 chainsaws, as well as the Partner 351, 350, the carburetor is adjusted using the N and L screws by setting the proportions of gasoline and air. If you let them go, then a large part of the fuel will be added and therefore the speed will be high, otherwise, on the contrary, they will fall.

Idling revolutions in partner chainsaws are regulated using a screw with the letter T, and in Shtil, as a rule, you need to look for the marking of the aircraft. The standard setting of the chainsaw is carried out during the final tests. Basically, after such settings, the percentage of fuel in the working mixture is more than air, which does not correspond to the optimal parameters. But they must be preserved in the first hours of operation during the break-in of the device. After that, the saw can be adjusted independently, but it will work well at the factory settings.

But if it is decided to regulate independently, then actions must be performed in the following sequence:

  • screw adjustment L;
  • then set the jet N;
  • then proceed to idle adjustment using the T screw (if the Stihl chainsaw is LA).

First screw L must be twisted in both directions in order to find the maximum engine speed. If that point is found, then turn the same screw by ¼, thereby slowing down a bit. If at the same time the circuit continues to idle, it is necessary to immediately turn the screw T (LA) until the chain stops completely.

After setting the maximum speed with the screw H, it is necessary to check the frequency with a tachometer. In the event that it does not match those indicated in the service book, the setting must be repeated. When a lot of smoke comes out at the maximum speed from the exhaust pipe, the mixture is too rich in fuel, if you hear noises and the engine heats up very much, on the contrary it is poor. Then you need to adjust the idle speed. With proper tuning, the engine should sound at low revs and the chain should not move.

Chinese models

The carburetor adjustment of the Chinese chainsaw, for example, Carver, is carried out in almost the same way as the factory models. There are the same three main adjusting screws L, H, T. Sometimes such models have the ability to adjust idle speed. But as a rule, employees of specialized services and owners of such saws claim that setting up a quality Chinese chainsaw is not always possible immediately.

For classic Chinese models, screw L should be loosened 1.5 turns from the maximum value. Screw H must be loosened one revolution from the maximum. Idle turns are regulated in the same way.

Thus, self-adjusting the chainsaw carburetor is not a very complicated process and can in most cases be self-taught.

Chainsaw Carb Adjustment | My tools

A chainsaw is a complex unit whose operation is based on a two-stroke type internal combustion engine. For the operation of the internal combustion engine, the use of a carburetor is required. In this mechanism, fuel is mixed with air, and this mixture is fed into the engine cylinder for combustion. The operation of the internal combustion engine is largely dependent on the carburetor, which needs periodic adjustment. Adjusting the carburetor of the chainsaw can be done by yourself, but for this you need to know the instructions that are described below.

Chainsaw carburetor design

A carburetor is a device in which fuel is mixed with air and this mixture is fed into a cylinder for combustion. When burning, the crankshaft is driven, to which the drive sprocket is connected to actuate the saw set. the chain. The absence or malfunction of the mechanism in question will lead to the inoperability of the tool, so it is important that the device is serviceable and adjusted.

The chainsaw carburetor design consists of the following components:

  • Solid cast aluminum alloy housing. The use of aluminum for the manufacture of this mechanism helps to lighten the weight of the tool
  • Air diffuser located on the inlet side of the mechanism
  • Jets. valves that are used to control the flow of the mixture
  • Atomizer. a device from which the fuel mixture enters the cylinder combustion chamber
  • Float chamber. a device for creating and maintaining a certain level of fuel

A detailed design diagram of the device in question is shown in the photo below.

Chainsaw carburetor device

Setting up a carburetor for a chainsaw is an important step that every sawyer has to deal with. The chainsaw needs adjustment not only after purchase, but also in the following cases:

  • Before running the tool. How to configure the mechanism for the proper break-in of the chainsaw is described in detail here.
  • After the break-in process
  • After overhaul of the internal combustion engine
  • During operation of the tool, when there are malfunctions during operation and starting the motor

At the heart of the mechanism there are 3 screws for regulation (on some Chinese models 2 screws), which are the control panel for the user. It is with the help of these screws that the chainsaw carburetor is adjusted independently and quickly. You can adjust an important tool assembly even in the field, without the help of specialists.

How does a chainsaw carburetor work. the principle of operation

The work of the unit in question, despite its complex design, is simple and understandable even for beginners. The principle of operation is based on the following actions:

  1. As soon as the engine starts, the air damper opens
  2. In the narrowing area of ​​the diffuser 16, the flow of incoming air is accelerated, which is mixed with a gasoline-oil mixture
  3. The gasoline-oil mixture is fed through the jets at numbers 15 and 12, and the air, before passing through the shutter 7, passes through the filter placed in front of the inlet
  4. The damper 8 is located behind the diffuser, and serves to control the flow of the mixture into the combustion chamber
  5. Screws 17 and 10 adjust the amount of gasoline that passes through the jets. On the carburetor control panel, these screws are labeled L and H
  6. The needle valve 11 controls the volume of the fuel mixture in the float chamber 14. To adjust the position of the needle valve, a membrane 13 is installed in the mechanism
  7. Another membrane 4 is responsible for supplying fuel to the combustion chamber of the cylinder. The position of this membrane depends on the number of revolutions of the engine
  8. A fine filter is used to clean the gasoline-oil mixture.

Chainsaw tuning screws

The simple principle of the carburetor ensures the smooth operation of the internal combustion engine. The quality of tuning determines how the tool will behave at idle and during operation. The mechanism under consideration has a direct impact on the performance of the entire tool. The tool life depends on the quality of adjustment.

Adjustment of the carburetor fuel-air mixture supply mechanism. when it is needed

The first carburetor adjustment of the chainsaw is done immediately after purchasing a new tool. This is done in order to run the tool motor. To run the ICE chainsaw, you need to limit the maximum speed, which is done using the tuning screws. As soon as the run-in is completed, which lasts 2-3 tanks of burned fuel, it is necessary to make adjustments again, but only now in order to establish the maximum number of revolutions.

Video: How to Open the Huter Trimmer Coil Cover

In addition to running, chainsaw carburetors are configured when:

  1. Knocking down settings after running
  2. If the engine does not start well
  3. If the engine does not develop speed or when you press the gas, the chainsaw stalls
  4. The wear of the piston group, but only in this case, the adjustment of the carburetor of the chainsaw is a temporary measure, since the internal combustion engine needs a major overhaul
  5. If the engine does not keep idle
  6. Unit vibrations
  7. Existence of a deposit on a spark plug
  8. Increased fuel consumption. This phenomenon can be detected by excess smoke. If you unscrew the candle, it will have a black color with soot

Where are the carburetor adjusting screws

Many malfunctions during the operation of a gasoline unit arise precisely because of the incorrect adjustment of the carburetor of the chainsaw or when they are knocked down. To restore the instrument to its previous performance, you will need to adjust the mechanism. Many beginners trust this process to specialists, for which the masters take a lot of money. It’s time to deal with the adjustment, and conduct it yourself, as this process does not require disassembling the mechanism.

It is interesting! The carburetor needs not only tuning procedures, but also flushing when dirt gets inside. Flushing involves disassembling the mechanism, and cleaning each part in gasoline or kerosene. However, such a procedure is carried out no more than 1 time in 3-5 years, which depends on the development of the tool.

Chainsaw carburetor adjustment

Setting up the carburetor of the chainsaw begins with the preparation procedure. The basis of preparation is the implementation of such actions:

  • Check the air and fuel filters for contamination, and if so, clean these elements
  • Check for damage to the membrane.
  • Needle Valve Service
  • Lack of air leakage, which can occur due to leaky seals, gaskets and seals

After making sure that the carburetor is working, you can adjust it yourself. You can restore the mechanism to factory settings, but you do not always need to do this. Instructions on how to adjust the carburetor on Stihl, Husqvarna, Makita, Dolmar, Champion, Sadko and others chainsaws are described below. Initially, we find out what each screw in the mechanism device is for:

  1. Screw H. the main jet, which is responsible for setting the maximum number of revolutions of the tool
  2. Screw L. jet XX, which is needed to set low idle
  3. Screw LA or S or T. increase and decrease the amount of mixture fed into the cylinder

Adjusting screws what do they mean

It is interesting! There are mechanisms on which two or even one adjusting screw is located, which is called LD for air supply (on Stihl 180 and 170 chainsaws). This is done in order to simplify the process of adjusting the carburetor of the chainsaw in an unprofessional way.

Each type of tool of the Stihl, Husqvarna, Makita, Dolmar, Partner brands is accompanied by an instruction in which there is a section where this process is described in detail. It will not hurt if, before setting up, you find the instructions, and read it before turning the screws.

Preparation for setting up the carburetor of the chainsaw includes the following manipulations:

  1. Do-it-yourself chainsaw installation on a flat surface. It is also recommended to fix the tool so that it does not move when exposed to the screws with a screwdriver
  2. Point the tire away from you
  3. Ensure a safe distance for others, as the chainsaw carburetor is adjusted with the engine running
  4. There is no need to remove the carburetor from the unit for its adjustment

The process of setting up the chainsaw mechanism:

The regulatory process is not over yet, but the tool can already be checked in action. For beginners and inexperienced filers, the setup process is recommended to be completed on this. For more precise adjustment of the carburetor of the chainsaw, you need to set the maximum speed. Getting started with setting the H screw for experienced filers:

  1. We determine the enrichment of the mixture by exhaust. To do this, we develop revolutions to the maximum, and look at the nature of the exhaust. The presence of bluish smoke and strong vibration of the instrument indicates excessive enrichment of the mixture
  2. The tachometer (if connected) will show a large number of revolutions. more than stated in the specifications
  3. To reduce the maximum speed, you need to move the screw H a few turns counterclockwise
  4. The maximum revolutions are checked again, and the process is repeated again if necessary.

It is interesting! You can determine the lean mixture by such signs as the squealing of the engine, its rapid heating, interruptions in ignition and detonation. It is impossible to allow a lean mixture, since it will lead to a quick failure of the cylinder-piston group.

You can verify that the tool is configured correctly by the following criteria:

  1. The chain does not idle
  2. The engine works like a four-stroke engine
  3. When you press the throttle, a quick response of the motor and a set of revolutions

To make the most accurate tuning, you will need to use a wired or wireless tachometer.

Tachometer for fine tuning

On the Stihl 170 and 180 chainsaw, the process of setting up the carburetor of the chainsaw looks a little easier, since there is only one screw. A detailed description of the carburetor control process on a Stihl MS180 chainsaw is presented in the video.

How to adjust carburetor on a Chinese instrument

We will figure out how to properly adjust the carburetor on the Chinese chainsaw of different brands. The setting principle is similar to that described in the material above. First you need to inspect the tool, and identify the presence of adjusting screws. Typically, screw T is located on top, and screws L and H are lower. To access these screws, it is not always necessary to remove the protective cover or cover.

If the Chinese chainsaw has a different number of screws, then based on their number, you need to carry out the appropriate settings. The device and the principle of operation of all chainsaws of different brands and manufacturers are approximately the same, therefore, there will be no problems with the adjustment.

It is interesting! Electric saws are installed on the saws, which do not need the use of carburetors, so they do not need to perform tuning manipulations.

It is always easy to carry out any even new work, if there is an instruction, so do not be afraid to take on the setup. Even if you do something wrong, then contacting a specialist, he will certainly indicate your mistakes. If you are having difficulty adjusting the carburetor of the chainsaw, then describe them in the comments. Specialists, craftsmen and just amateurs together with the founder of the portal will help you figure this out.

Related Publications

How to adjust the chainsaw carburetor yourself, the correct adjustment and repair

A hand-held chainsaw is an excellent assistant in the personal household, which is indispensable in the preparation of firewood, pruning tree branches, as well as in the construction of wooden log cabins for houses, bathhouses and outbuildings. The design of saws allows you to file and saw trunks of medium-sized trees.

Currently, there is a large selection of chainsaws on the market, among which are the Partner chainsaws of the Swedish concern Husqvarna and the Huter chainsaws of the same German company, for their compactness, lightness, performance and reasonable prices.

The ease of maintenance of Partner and Huter saws allows even the first person to pick them up to handle them, but, nevertheless, a chainsaw is a complex device and requires a careful attitude. In the process of work, various kinds of malfunctions sometimes occur that affect effective operation, and the user must be able to cope with them.

How to adjust a carburetor on a chainsaw

The most common problem encountered during the operation of chainsaws is the incorrect operation of the carburetor, which leads to excessive consumption of fuel and a decrease in power, so any user should know how to configure the carburetor on the chainsaw.

Chainsaw carburetors are also designed as automobile carburetors and therefore anyone who is familiar with the principle of the internal combustion engine is able to cope with the carburetor adjustment and can adjust it with their own hands.

By the manufacturer, new saws are delivered with an adjusted carburetor, but during operation the standard setting is violated and the saw requires re-setting. The documentation that came with the saw describes how to adjust the carburetor.

Carb adjustment needed when the following symptoms appear:

  • at idle, the saw runs at high speeds;
  • at work it smokes a lot;
  • it starts poorly both in a cold state and in a warmed up one;
  • works at low revs and with reduced traction.

The device and principle of operation of the carburetor

The device and principle of operation of the carburetor of a chainsaw are the same as those of carburetors of internal combustion engines and perform the same function: preparing and supplying a mixture of air with fuel to the combustion chamber of the engine.

The carburetor consists of the following parts:

  • housing;
  • float chamber;
  • needle valve;
  • float;
  • atomizer;
  • fuel jet;
  • mixing chamber;
  • throttle body;
  • diffuser.

Atmospheric air, passing through the air filter, enters the air channel of the carburetor, where there is a diffuser, which reduces the diameter of the channel, as a result of which a reduced pressure is created behind the diffuser.

Behind the diffuser throttle installed, which regulates the flow of air entering the carburetor. By partially blocking or opening the air channel, the damper controls the air flow, thereby regulating the engine speed.

Under the action of reduced air pressure created behind the diffuser, gasoline from the float chamber is sucked into the mixing chamber through the fuel nozzle and atomizer.

In the chamber, the fuel is mixed with air, forming a fuel mixture, and then fed into the combustion chamber. The throttle is mechanically connected to the fuel jet, which controls the amount of fuel supplied to the atomizer. Therefore, it simultaneously regulates the flow of air and fuel into the combustion chamber.

The float controls the fuel level in the float chamber, keeping it at the same level. It is connected with a needle valve that blocks the flow of fuel into the float chamber.

When the fuel level drops, the float lowers and moves the needle valve, causing him to tear off the fuel feed hole. When fuel fills the chamber to a normal level, the float moves the needle to the closed position.

Engine speed depends on how much mixture of fuel and air enters the combustion chamber. The more we open the shutter, the more turns.

How to set up a carburetor on a chainsaw?

Carburettor adjustment consists in adjusting the nozzle and the air damper so as to obtain the optimum ratio of the amount of air and fuel in the fuel mixture.

If there is a lot of air in the fuel mixture and there is a lack of fuel, the mixture is lean, therefore the engine power is reduced.

If a lot of fuel and lack of air. the mixture is oversaturated, incomplete combustion of the fuel occurs, which leads to smoke, soot on the piston and in the exhaust pipe and increased fuel consumption.

How to adjust the carburetor?

Consider partner carburetor adjustment as an example.

For adjustment, you need to have a slotted screwdriver and a tachometer device that allows you to measure the engine speed.

Setup is carried out in the following sequence:

  1. setting the carburetor of the chainsaw at low speeds;
  2. adjustment at maximum speeds;
  3. fine tuning to work at idle;
  4. checking the saw in all modes.

It is necessary to start after the engine has run and warmed up.

Chainsaw Adjustment performed using three adjusting screws on its body:

  • screw L. adjustment of fuel supply at medium and low speeds
  • screw N. at high speeds;
  • T screw. in idle mode.

If the carburetor is completely misregistered and the engine does not want to start, set the adjustment screws L and H to the standard setting position: first tighten them completely, then unscrew them half a turn.

Start the engine and let it warm up, then proceed to adjust low revs using the L and T screws.

To do this, screw L to be unscrewed until the maximum engine speed is reached, and then screw in ¼ turn, and set the idle speed with screw T.

Next, to tune to maximum speed tighten screw H slowly, achieving the maximum speed according to the tachometer.

After completing the adjustment, it is important to check the operation of the engine in all modes. To do this, drown it and let it cool.

Then start the saw in cold start mode and monitor the engine idling. If gas smoothly increases and decreases, and the chain does not move, the adjustment is made correctly. Next should be checked during sawing. If there is a loss of power, carry out the adjustment again.

DIY carburetor repair

Carburetor is easy to disassemble, therefore, you can repair the carburetor of the chainsaw yourself. For example, if necessary, it is quite possible to do the following operations with your own hands:

  • replace the gasket under the cover of the main camera;
  • flush or replace the fuel filter;
  • Replace needle valve and fuel pump diaphragm.

Before proceeding with disassembling the carburetor, it is necessary to clean the dirt from the surface of the housing, as it can get into the carburetor and clog the holes of the needle valves and the nozzle.

Next, you should undock the mountings of the air and throttle control rods, dismantle the air filter and remove the cover of the main chamber by unscrewing the mounting screws. After that, you can begin to replace the above parts.

Very often, the cause of not starting the saw may be defects in the ignition system, in particular, candles due to the following reasons:

  • candle soot. indicates poor-quality oil or improper carburetor adjustment;
  • filling the spark plug with fuel. incorrect carburetor adjustment.

To check the condition of the candle, unscrew it with a special key from the cylinder head.

Nagar on a candle removed with a needle or awl, and if necessary with a sandpaper, then put it in place and try to start the engine.

We wipe the filled candle with a rag, dry it, put it in place and try to start the saw.

In some cases, the engine smokes and stalls at high speeds. The reason may be the clogging of the muffler with exhaust products, so you need to remove the muffler, rinse carbon deposits with gas, wipe, dry and put it back in place. While the silencer does not stand still, the exhaust outlet should be covered with a rag to prevent dirt from entering.


Setting up the carburetor of the saw and its minor repairs can be done without experience, but in order to do this correctly, you need to follow the algorithm prescribed in the attached documentation. However, you should not overestimate your strength, because sometimes it is cheaper to pay a specialist for quality service than to eliminate the consequences of your unprofessional repair.

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Chainsaw carburetor. device and adjustment, video

A carburetor is one of the most important components of any modern chainsaw. Its main task is to mix the fuel mixture with air, as well as to further supply the finished fuel to the cylinder of the gasoline engine. During operation of the chainsaw, its carburetor is constantly working, therefore, over time, this unit begins to need adjustment and flushing. Performing these procedures is quite simple, if you are extremely careful and follow the correct procedure.

Chainsaw carburetor device

Almost all carburetors used in the production of chainsaws have one and the same device. The only difference is the mechanisms with which Chinese garden tools are equipped.

As standard, the fuel assembly consists of the following parts:

  • float chamber. this element is designed to continuously maintain the required amount of fuel. During the operation of the unit, fuel is transmitted through the built-in nozzle to the atomizer;
  • tube. through it, fuel flows in portions into the chamber. The fuel supply is regulated by the position of the integrated factory shutter;
  • atomizer. this part is necessary for injecting fuel into the intake air stream.

The principle of operation of the carburetor chainsaw is quite simple. During operation of the unit, air is sucked in by the tube and passes through it at a speed that is controlled by the integrated damper. With the opening of the damper, a float located in the chamber is activated. After passing through the diffuser, air is mixed with fuel and instantly atomized. Further, a high-quality fuel mixture enriched with air passes through the inlet channel and enters the engine cylinder. Visually about the operation of the carburetor will tell the scheme.

The fuel in the assembly circulates under pressure. In the float chamber, it is close to atmospheric, and in a regular tube, the intake air is more rarefied. Due to the difference in the pressure indicators formed, the fuel mixture enters the tube. The greater the amount of fuel, the higher revolutions the engine of an economic chainsaw is able to create.

How to wash a carburetor chainsaw?

You can clean the carburetor on a chainsaw using any aerosol cleaner. The products of Mannol, Hi-Gear and Nowax brands have proven themselves best. These compounds clean the walls and parts of the carburetor well of accumulated dust, soot and hardened resin.

Both Chinese and German carburettors are rinsed in the same sequence.

The carburetor on the chainsaw is cleaned in the following order:

  1. First, use the fuel remaining in the fuel tank. Next, you need to unscrew the mount and remove the protective cover of the chainsaw body, as well as remove the standard air filter;
  2. Next, you need to remove the hose, which is responsible for the supply of fuel. To do this, open the clips. After that, you need to unscrew the fasteners and remove the top cover of the factory assembly;
  3. Next, you need to dismantle the cover with a blue gasket, which acts as the membrane of the fuel pump. Staples in the form of springs are located next to the housing. They will need to be removed, as well as the screws removed;
  4. Then you need to unscrew the screw and carefully remove the needle valve. Directly below it is a built-in spring, which also needs to be removed. After that, you need to pull out the shutter and the standard axis, gently pulling them along towards you;
  5. After that, you will need to remove the drive lever, as well as the throttle damper and its factory axis;
  6. All the extracted parts of the carburetor of the chainsaw will need to be laid out on paper and check their integrity. If necessary, worn parts must be replaced;
  7. Then, all dismantled parts must be flushed with spray can. The same thing needs to be done with the float chamber and the carburetor body.
  8. After complete drying, all parts must be installed in the reverse order.

Chainsaw Carb Adjustment

This procedure is necessary specifically in cases where the household garden tool does not start or, after starting, immediately stalls. Setting up the carburetor of the chainsaw is also needed when its power has dropped or the amount of fuel consumed has noticeably increased.

For independent adjustment, each manufacturer includes adjustment screws in the set of his garden equipment. The bolt marked with the letter H serves to adjust the position of the main jet and the internal combustion engine at high speeds. The bolt L is necessary for basic adjustment of the built-in idle speed generated by the jet motor. Accordingly, the T-screw is required by the owner of the chainsaw to quickly adjust the idle speed of the factory engine. In some cases, this bolt is also marked with the letters S or LA.

How to adjust the carburetor on a chainsaw?

Before setting up a carburetor on a chainsaw, you need to carefully prepare for the procedure. First of all, it is necessary to find in the operation manual descriptions of the angle of rotation of the adjusting screws. If you turn the bolts arbitrarily, not following the manufacturer’s instructions, this can lead to serious damage to the internal combustion engine of the tool.

The motor itself must be in good condition. Before setting, the air filter must also be thoroughly cleaned. Otherwise, it will not be able to pass air in the volume required for the enrichment of the fuel mixture, which will lead to incorrect carburetor tuning.

The adjustment of the assembly must be carried out on a flat surface. The saw itself must be installed so that its saw set is located away from the legs and face of the operator. Immediately before tuning, you will need to remove the upper part of the protective plastic tool case, as well as remove the foam and part of the standard air filter. To perform the configuration of the node, you need a thin curly screwdriver.

You need to adjust the chainsaw carburetor in 2 stages. The first of them is basic. During its execution on the switched off chainsaw with a cold engine, it is necessary to screw in the bolts H and L one by one in the direction of the clock hand until it stops. After that, each of the screws will need to be unscrewed by 1.5 turns in the opposite direction.

The final carburetor adjustment is performed in the following order:

  1. First you need to start a chainsaw and give it time to completely warm up the engine. In this case, the throttle lever must remain in the middle speed position;
  2. Next, the screw responsible for the idle speed of the motor will need to be slowly turned in the direction of the clock. This should be done until the internal combustion engine of the saw does not work stably;
  3. If during stable operation of the motor the chain moves along the tire, it means that the same bolt needs to be slightly unscrewed in the direction counterclockwise;
  4. Then you need to connect a manual tachometer to the motor. With it, you need to find high and low ICE work. To do this, the adjusting bolts H and L must be turned alternately in different directions until the indicators indicated in the operating instructions are displayed on the device.

At the end, the used chainsaw will need to be drowned out and wound up again. It should work stably at idle, and its chain in this mode should not rotate on the bus. When the trigger is pulled, the saw should quickly gain momentum, and when released, reset it.

What to do if gasoline does not enter the carburetor of the chainsaw?

The first reason for this breakdown is the clogging of the fuel filter with dust and dirt. This is due to the presence of a large amount of harmful impurities in gasoline and used engine oil. Over time, they accumulate on the surface of the filter, because of which it loses its ability to pass fuel. To solve the problem, you will need to thoroughly clean the filter by rinsing it in a bath with a cleaning agent. If holes or other signs of wear appear in the filter, it must be replaced immediately.

The second reason for the breakdown is the contamination or breakage of the tube through which fuel is fed into the carburetor. If the hose is not torn, then for cleaning it will be enough to thoroughly blow it with compressed air from an aerosol. If the tube is broken, it will need to be replaced. When installing the hose, its joints with the fittings must be carefully treated with sealant.

There is another malfunction, which is much less common than the previous two. It consists in breaking the damper regulating the speed of fuel supply to the carburetor. If dust or small shavings get inside its mechanism, the shutter is blocked and remains in the closed position. Repair of the unit can only be done with the replacement of the damper, as it, most often, can not be restored.

Why is a chainsaw shooting at a carburetor?

Often, malfunctions of the carburetor of the chainsaw are associated with loud extraneous sounds that are heard from the side of the unit. Ignoring them will lead to even more serious failures, which will be much more difficult to eliminate.

First of all, you need to deal with the causes of extraneous sounds. The first of them is an incorrectly set ignition, because of which the fuel used does not have time to burn in time in the engine cylinder. This leads to the formation of short-term firing noise, repeated during each cycle of fuel supply to the cylinder.

To eliminate the malfunction, you need to adjust the gap between the flywheel and the standard ignition coil of the chainsaw. To do this, remove the left protective cover of the plastic case and clean the parts underneath. There are 2 screws to the right of the ignition coil, turning them counterclockwise will move the flywheel away from the standard coil. Next, you will need to attach a template to the side of the coil and begin to slowly turn the factory screws in the opposite direction. As soon as the built-in flywheel comes close to the previously installed template, the rotation of the screws will need to be stopped.

After adjusting the ignition gap, you need to check the operation of the chainsaw. If she still shoots, then you need to inspect the candle. If soot has accumulated on it, the part must be cleaned and completely dried.

Another reason the used chainsaw shoots is because of the wrong proportion of the prepared fuel mixture. If there is too little gasoline or engine oil in it, then the garden tool engine will not be able to work stably. In this case, you will need to completely drain the fuel and prepare the mixture in accordance with the manufacturer’s instructions.

How to extend the life of the carburetor?

To prevent damage to the standard site, the owner of the garden tool should adhere to a number of rules. These include:

  • the use of a properly prepared fuel mixture. with each mixing of gasoline and engine oil, the proportions specified in the operating instructions must be strictly adhered to;
  • use for the gasoline of the brand that the manufacturer indicates. for the operation of an engine running on AI-92 gasoline, AI-95 fuel will not work, and vice versa;
  • regular washing. cleaning the unit of dust and dirt accumulated on the walls will facilitate its daily work;
  • setting the unit when immediately after detecting a problem. no need to delay the carburetor adjustment, as this can lead to even more serious damage.

During operation of the chainsaw, you must ensure that dust, sawdust and small debris do not leak under its body. Otherwise, they will quickly clog the carburetor and block its operation.

how to properly adjust the Husqvarna-5200 and configure idle on the Stihl-180 with your own hands

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.

Carburetor parts

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

  1. The basis. 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.

Not sure which chainsaw to choose? Read our article.

Looking for cheaper models, but reliable and time-tested? Pay attention to Russian-made chainsaws.

Or explore overseas chainsaw manufacturers such as Stihl.

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.

Chainsaw Air Filter

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.

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.

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:

    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.

    Top cover removal

    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.

    Chinese model of chainsaw

    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.

    Read also what to do if the chainsaw does not start, which nozzles for the chainsaw are best to choose, and how to sharpen the chain of the chainsaw at home.

    About which chainsaw to choose. read here.