How to adjust the carburetor on Husqvarna 40

In what cases does the carburetor of a Husqvarna chainsaw require adjustment?

There are a lot of problems that can be solved by adjusting the carburetor. Adjusting the carburetor of the Husqvarna chainsaw is necessary when malfunctions such as:

• increased idle speed;
• strong smoke when operating the tool;
• difficulty starting a cold or hot engine;
• lack of traction and reduced maximum speed.

This is by no means a complete list of problems that can be solved by tuning the Husqvarna carburetor. In some cases, adjusting the quality and quantity of the fuel mixture is carried out after a major overhaul of the engine or during scheduled maintenance of the chainsaw.

]Husqvarna AB[/anchor] recommends adjusting the carburetor before and after running in the saw.

The design and principle of operation of the Husqvarna carburetor

To successfully configure the Husqvarna chainsaw carburetor, you need to know its structure and understand how it works. In fact, everything is not as complicated as it seems at first glance.

The saw carburetor has a built-in fuel pump, which is responsible for transporting the mixture of gasoline and oil, as well as a diaphragm, a needle valve with a rocker arm. Their joint work makes it possible to dose the fuel supply to the main chamber and two dampers.

One of the dampers is designed to regulate the flow of fuel into the cylinder when you press the gas, it is called the throttle, the second is responsible for limiting the flow of air from the air filter to facilitate starting a cold Husqvarna chainsaw.

At the moment when the operator shuts off the air supply to the carburetor using the air damper, the fuel mixture becomes leaner and its supply to the cylinder increases, due to which the chainsaw starts much easier than when a cold start is carried out in normal mode.

The operation of the Husqvarna carburetor involves a valve-nozzle, which atomizes fuel and prevents air from entering the main chamber. Often problems with saw operation can be caused by defects in this particular element.

For example, if the chainsaw is stored improperly, the valve may stick, the fuel supply will stop, which will make the engine impossible to operate. Also, malfunctions in the operation of the nozzle can cause air to leak into the main fuel chamber of the carburetor. In such cases, adjusting the position of the adjusting screws will not correct the situation; repair or replacement of the unit will be required.

Three adjusting screws installed in the carburetor body are responsible for adjusting the quality and quantity of the mixture, as well as the number of crankshaft revolutions in idle mode:

• screw (L) – regulates the amount of fuel in low and medium speed modes;
• (H) – responsible for traction at high speeds and their number;
• (T) - changes the position of the throttle valve, thereby regulating the amount of fuel mixture entering the cylinder and the operation of the tool engine in idle mode.

Attention! Screws (L) and (H) cannot be adjusted without specific knowledge and experience. Incorrect adjustment of the quality and quantity of the fuel mixture can cause the engine to stop working or operate incorrectly, causing it to wear out quickly or even seize.

Husqvarna 142 chainsaw carburetor design

The main part of the carburetor is a body equipped with gaskets. An integral part of the carburetor is the fuel pump, which is responsible for supplying the fuel mixture. An important component is the float chamber. Fuel accumulates here, the level of which is regulated by a special float. As it accumulates, the fuel moves into the main chamber, where it combines with air.

Each damper has its own purpose. One of them is throttle. Its main task is to adjust the fuel supply to the cylinder. The other is needed to contain the flow of air from the air filter. At the moment the second damper closes the air supply, the fuel mixture becomes depleted, as well as its supply to the cylinder increases. This is necessary to ensure easy starting of the power tool. A nozzle valve takes part in the operation of the carburetor, which atomizes the fuel and prevents air from entering the chamber.

Often, the malfunction of this particular valve is the cause of unsatisfactory operation of the unit. For example, due to the incorrect position of the chainsaw during storage, the valve may jam, which will cut off the fuel supply, and the saw simply will not start. Due to malfunctions in the injector valve, air may leak into the main fuel chamber of the carburetor. The failure of this part can paralyze the operation of the entire unit. Since quite a bit depends on the condition of this valve, and the operation of the entire engine. If it is found to be faulty, it is recommended to buy a new one and replace it.

Tools required for work

Before you start setting up the Husqvarna carburetor, you need to make sure you have all the tools that may be useful. To carry out this type of work yourself, you will need:

• screwdriver for adjusting screws (H) and (L), in specialized stores they have very high prices, so we recommend buying such screwdrivers as a set from Aliexpress; in our service we use such a set;
  Read also:  How to properly adjust the carburetor of a Husqvarna chainsaw with your own hands
• electronic tachometer to determine crankshaft speed readings (with some experience, you can adjust by ear), in our tool repair service we use a high-quality and inexpensive analogue, which can be ordered on aliexpress using this link;

• Phillips screwdriver , for adjusting screw (T);
• compressor with a blow gun for cleaning the saw before work.

A regular slotted screwdriver will not work for adjustment , since the adjustment screws on Husqvarna chainsaws can have a different cross-section. You will have to purchase a special one, this is a feature of repairing Husqvarna chainsaws; they did everything so that the saw could be repaired only in a specialized Husqvarna service center.

Algorithm and description of Husqvarna carburetor settings

The Husqvarna carburetor is adjusted in the same way as carburetors on chainsaws from other manufacturers are adjusted.

Immediately before adjustment, it is necessary to conduct a complete diagnosis of the saw and make sure that there is no difficulty in supplying fuel or air leaks into the crankcase of the chainsaw . You also need to make sure that the air filter is clean and, if necessary, replace it with a new one.

Work order:

1. On the muffled saw, the factory settings of the Husqvarna carburetor are installed.
2. The engine starts and the saw warms up for several minutes.
3. By turning the screw (L) clockwise, the position at which the engine develops maximum speed is found, after which the screw must be turned back 1⁄4. If the chainsaw chain rotates, then it is necessary to reduce the idle speed by adjusting the position of the screw (T).
4. The next stage is adjusting Husqvarna's power at maximum speed and adjusting its quantity. To do this, the tachometer is connected to a running chainsaw, the throttle is squeezed to full, after which the tachometer readings are checked. If the maximum speed value differs from the maximum number recommended by the manufacturer, then by changing the position of the screw (H), the tachometer readings are returned to normal.

Adjusting the Husqvarna 142 carburetor

The carburetor of the 142 Husqvarna chainsaw is adjusted in several directions. Since the carburetor is responsible for mixing fuel with air in optimal proportions, one of the areas of adjustment will be the quality of the fuel mixture. The second direction of adjusting the chainsaw carburetor is associated with a decrease in the supplied fuel. The need for such adjustment is often due to incomplete combustion of the fuel and its release in the form of thick smoke.

Tools needed for adjustment work:

1. Special screwdrivers for adjusting screws (purchased in specialized stores);
2. Tachometer (some experienced chainsaw owners, in the absence of a tachometer, rely on hearing);
3. Crosshead screwdriver;
4. Compressor with blow gun.

Before starting setup work, it would be good to diagnose the chainsaw. It is worth making sure that the filter is in good condition and does not require replacement. Check for fuel supply obstruction. Be sure to remove dirt and dust from the components and the chainsaw itself. Since adjustment will require disassembling the unit, it is necessary to remember the correct location of spare parts. The chainsaw operating instructions, which contain an assembly diagram, will help you avoid getting confused. But even if for some reason there is no diagram, you can film everything on your mobile phone camera.

So, we have the tools, the diagnostics have been carried out, let's start making adjustments.

Screw adjustment (L)

We begin setting up the Husqvarna 142 carburetor by setting the factory settings with the saw turned off. After this, start the saw and let it run for a few minutes. Next, turn the screw (L) in the direction of the clock hand until you find the moment where the engine gains the highest speed. Having caught the right moment, turn the screw a quarter turn in the opposite direction. If the chain moves, the screw (T) will need to be adjusted.

Screw adjustment (H)

Adjustment of the screw is done in the first 10 seconds of operating the engine at maximum speed. How to adjust the carburetor on a Husqvarna 142 chainsaw at the highest speeds. To set up, just turn the screw (H) a quarter turn clockwise. Having noticed that the maximum load has not been achieved, we repeat all the manipulations. To complete the adjustment, you will need a tachometer, which must be connected to the switched on saw. If insufficient adjustment is made, the running engine will make unnatural squealing sounds. In a situation where the adjustment is overdone, a large amount of smoke appears.

Screw adjustment (T)

Working with this screw is very simple. It consists of turning the screw in the direction of movement of the clock hand. The screw should be turned exactly until the second when the chain begins to move. As soon as the movement begins, the screw turns in the opposite direction until the chain stops moving.

The entire carburetor adjustment process must be performed in the same sequence as described above.

To evaluate whether the carburetor adjustment on the Husqvarna 142 was performed correctly, look at how the chainsaw operates after adjustment. The tool shows stable operation both at low and high speeds. The speed should be easy to pick up. The motor operates without unnecessary alien noise and does not stall. Check engine operation. It's easy to do. Press the gas trigger sharply several times. Please note that when you press the trigger, the speed should increase very quickly, and when released, it should decrease. If everything goes this way, then the setup was completed without errors. In addition to the need to adjust the carburetor if there is some malfunction of the tool, there are two more cases in which adjustment work is simply necessary. The first case is changing the fuel mixture used, and the second is before preparing for the summer season after wintering and vice versa. The owner of a power tool always has the choice to act independently or contact a service center to have this work carried out by specialists. You should not start setting up a carburetor without having any similar experience.

Unfortunately, adjusting the carburetor does not always help solve problems. Often, the cause of unsatisfactory performance of a tool can be the breakdown of one or another part. If you cannot find the cause of a particular malfunction on your own, then it is better to show your tool to professionals in a specialized service center. The work of specially trained people will cost much less than breaking a power tool with your own hands.

Nuances of adjustment

After the adjustment, the chainsaw should easily pick up and drop speed, and operate stably at low and high speeds. If the saw chain rotates at idle speed after adjusting the carburetor control screws, this is a sign that the adjustment was made incorrectly and the position of the screw (T) needs to be adjusted.

Also, when adjusting the Husqvarna carburetor, it is worth taking into account the response time of the chainsaw to the rotation of the screws. The settings do not change immediately, but within five or ten seconds.

One of the indicators of incorrect adjustment is heavy smoking when the saw is operating, which indicates a large amount of fuel entering the combustion chamber. If such a situation occurs, the position of the screw (L) must be adjusted.

How to understand that everything is done correctly

After setting up, you need to start the chainsaw. Check stability at idle speed. In this case, the chain should not move. When you press the accelerator, the chainsaw should accelerate steadily and stop without delay.

At minimum and maximum speed levels, the Husqvarna 350 should operate stably, without any extraneous noise. There should be no sudden loss of power or shutdown during operation.

Factory settings

The standard factory settings for the Husqvarna carburetor are the position of the screws (H) and (L), in which a working chainsaw should be guaranteed to start. For Husqvarna instruments, this is one and a half turns from fully tightened screws (H) and (L).

During the adjustment process, you must first set the screws to the standard position, then start the chainsaw and make precise adjustments to the power, the number of maximum revolutions and idle speed.

DIY carburetor repair

If, during a full diagnosis of the Husqvarna chainsaw, carburetor defects were discovered, some of them can be eliminated without contacting the Husqvarna AB service center. For example, you can do this yourself:

• change the gaskets under the covers of the main chamber and fuel pump;
• clean or replace the strainer;
• replace the diaphragm or needle valve of the main chamber;
• troubleshoot the fuel pump diaphragm.

Gaskets, diaphragms and a needle valve with a rocker arm can be found in the repair kit, which is available for each model of Husqvarna chainsaw carburetors.

Also, if you have some experience, you can try to restore a faulty injector valve , but you cannot guarantee a positive result when trying to restore an injector; if it malfunctions, manufacturers recommend replacing the carburetor completely. To do this, you need to perform the following series of actions:

1. Before removing the carburetor, clean the saw with a compressor, as dirt can interfere with quality repairs.
2. Next, open the top cover of the chainsaw, remove the air filter, disconnect the rods from the air and throttle valve control levers.
3. After this, unscrew the carburetor mounting screws.
4. Disassemble the carburetor body for repairs. Doing this is quite simple. The main chamber cover is held in place by four screws, which can be removed using a regular screwdriver; the fuel pump cover is secured with one wide screw.

Below is a video, after watching which you will understand exactly how you can repair the carburetor without contacting a Husqvarna service center.

Repair Husqvarna 142 Do It Yourself Video

Do-it-yourself repair of Husqvarna 142 chainsaws

Why you need to tune your Husqvarna carburetor

The carburetor is one of the important mechanical components that make up a chainsaw. In his tasks. mix fuel with air and feed the resulting composition into the engine. But during the operation of the chainsaw, situations arise when adjusting the Husqvarna carburetor becomes necessary. Depending on the reasons, the carburetor adjustment of chainsaw 142 and other series is performed to prevent the following situations:

• the presence of interruptions in engine operation, accompanied by its shutdown;
• excessive fuel consumption during operation.

Since the carburetor affects the quality of the fuel, in the first case the need for carburetor adjustments on the 137 saw or other professional series such as the Huskvarna 240 or 260 involves affecting enough combustible raw material entering the carburetor to mix with the air mass. It is known that maximum performance is possible only with a certain ratio of these substances. The second point in adjusting the carburetor mixer chainsaw is due to the lack of incoming air, which causes underheating of the injected gasoline and its output in the form of thick smoke. Timely changing the parameters with your own hands to reduce the amount of introduced fuel will significantly reduce the consumption of this product.

The repair itself will save not only the budget, but also the time spent on transportation and the queue in the workshop. The same applies to replacing various spare parts in a gasoline tool, such as a chain on a chainsaw or a universal trimmer head on a motor pump or oil for electric drives.

When you need to adjust your Husqvarna carburetor chainsaw

Neglecting deviations in the normal operation of a gasoline tool risks the fact that even with a strong desire, adjusting the carburetor of a Husqvarna chainsaw may be useless, and it will be necessary to replace either this unit or engine components subject to prolonged thermal or mechanical stress. Therefore, as soon as the saw shows the first deviations, it is necessary to carry out immediate repairs in the form of simple corrective actions. Among these changes in work we note:

1. The chainsaw slows down too slowly;
2. The tool does not reach maximum power and falls quickly when loaded;
3. The engine stops frequently;
4. The chain saw makes a lot of noise when operating;
5. The chainsaw releases an uncharacteristic amount of smoke, increasing at each stage of load.

As soon as you notice any of the listed deviations, it is necessary to urgently adjust the carburetor of the 435 scythe or a slightly strengthened copy of the Husqvarna 55 saw. Timely maintenance also portends the absence of waste for a complete replacement of spare parts and drive units and the fuel system of the chainsaw. Therefore, with the difficulties in the operation of the Husqvarna 340 carburetor system and all other tuning lines, they will save both the chainsaw and the work processes, as well as the owners’ money. If necessary, you can order the infusion of mechanisms, replace spare parts, and also buy a trimmer line with tips for its self-installation.

Do-it-yourself Husqvarna carburetor adjustment

In all Husqvarna chainsaws, Husqvarna carburetor adjustment occurs in a similar way, since all products have the same set of mechanisms. For example, if you are tuning systems in 236 series gasoline tools, the process is followed by finding the highest idle speed by slowly turning the adjustment screws L. for low speed jet, T. for high speed jet and idle adjustment. The self-tuning process consists of several periods associated with the rotation of screws L and H, which control the throttle valve to supply the fuel mixture and adjust the screw T, adjusting the idle speed. Depending on the insertion parameter, the saw is adjusted in the following sequence:

Disassembling the HUSQVARNA 142 chainsaw

Husqvarna chainsaws

137 and
142
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Quick repair of Husqvarna 137/142. Replacing the oil pump.

A hare to feed the Chinese and thugs! Disassemble and clean the carburetor, replace dry diaphragms, tighten and...

1. After warming up, turn screw L to maximum idle speed. Once they are found, turn the drive in the direction of decreasing the rotation speed by ¼ turn of the screw. If the chain begins to rotate, screw T is adjusted along the stroke until the chain stops.
2. Adjustment of screw H on the carburetor of the power saw takes place during a 10-second period of running the engine at full speed, passing ¼ turn. If the maximum load is not reached, the operation is repeated. Under-adjustment will result in a squealing sound, while over-adjustment will cause the muffler to release more smoke.
3. Adjustment of the T of the idler screw is carried out one at a time during the stroke until the chain begins to rotate. Once this happens, the screw is tightened until this mechanism stops.

Of course, adjusting your carburetor settings will allow your tool to perform as efficiently as possible, but don't forget about lubrication. Kosa Motors recommends purchasing special-purpose chain saw oil for machinery, as timely maintenance will give the tool an additional period of quality service.

The instructions describe in detail the following: composition, safety, etc. back, sawing rules, maintenance, etc.

Husqvarna 142 carburetor adjustment video. The reason for carburetor breakdown and carburetor adjustment (tuning) on ​​chainsaws. How to properly adjust the carburetor on a Husqvarna chainsaw. Review of the Husqvarna 142 chainsaw from a user.

To download the Husqvarna chainsaw manual, click on your model name in the download file (Husqvarna 142.E.pdf). Chainsaw Husqvarna 142. Review and reviews from the owner of the saw of this company. NOT a manual, not an instruction manual b n.

Adjusting the chainsaw carburetor. At the request of the audience. Chainsaw maintenance. Part 11. Adjusting the carburetor on a Chinese chainsaw (practice).

Ask to see another saw from stock, they will be random. Instructions for chainsaw Husqvarna 137-e and Husqvarna 142.e. After 20 people under the Husqvarna 142 have formed a decent puddle of oil, be sure to check the instructions that there is no system.

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Video instructions for working with Husqvarna chainsaws. Demonstration of the legendary Husqvarna 142 (Demonstration of Husqvarna 142).

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