Adjusting the carburetor chain saw Husqvarna 142 with their own hands

Adjusting and tuning the Husqvarna 137 carburettor

adjusting, carburetor, chain, husqvarna

In the picture above you see three screws for adjustment. each of them has a different function: screw T is necessary for adjusting the idle RPM. The L screw is for the low speed adjustment. Screw H adjusts high RPM.

To adjust: First, with the L screw (by turning it) we are looking for the highest rpm at idle. After we have found them, it is necessary to turn this screw a quarter turn against the clock hand. If the chain keeps turning in this position, turn the T screw to stop the chain. Then we warm up the engine at full throttle for about 10-15 seconds and turn the screw H a quarter turn counterclockwise. Wait 10 seconds and listen. the engine should sound like a 4-stroke. If you hear a squealing noise, the mixture is lean (turn the screw back), if there is a smoke, the mixture is enriched (turn the screw back).

After adjusting low and high RPM, adjust idle RPM with the T-screw. This is done as follows: 1.The engine should run 2.Turn the screw T clockwise until the chain starts to turn. 3.Turn the screw the other way until the chain stops.

If your carburetor is properly adjusted your chainsaw will run fast and sound like a four-stroke engine.

Remember, you need a tachometer and experience to properly adjust your chainsaw carburetor. So it is better to apply to a specialized service!

Buy Husqvarna 137 carburetor and other parts

A video about adjusting the chainsaw at idle:

Here is another video about repairing your Husqvarna carburetor.

How the carburetor works on a Husqvarna 137 chainsaw?

These chainsaws are most often equipped with a Walbro carburetor from the factory. Before you can adjust the Walbro carburetor on your Husqvarna chain saw, you must have a basic understanding of its construction and know how it works.

What is the fuel-oil mixture

To precisely deliver fuel and oil, operation of a fuel pump that is driven mechanically from the crankshaft is used. The carburetor itself is equipped with a diaphragm and a special needle valve, which are responsible for regulating the pressure in the system. Thanks to them, proper operation of dosing chambers and pump is organized, which improves chainsaw performance.

Fuel mixture preparation

gasoline and oil in the ratio 15:1 by volume should be used in your chainsaw, t. е. Add 1 liter of oil to 15 liters of gasoline and mix the mixture thoroughly. The amount of gasoline and oil in the fuel mixture is given in this table:

Petrol.л 1 2 3 4 5 6 7 8 9 10
Oil, l 0.06 0.13 0.20 0,26 0,33 0.40 0.46 0.53 0.60 0,66
Fuel mixture, l 1.06 2,13 3,20 4,26 5,33 6.40 7.46 8.53 9.60 10.66

ATTENTION! Application of oils: Lukonoi-2T; TNK-2T OIL: AZMOL Sport 2T GD” and Dr., and waste oil in the fuel mixture will cause the connecting rod needle bearing to fail.

What is responsible for the air supply

The air supply is provided by two dampers mounted on the diffuser chamber. The first can regulate the amount of air when the gas pedal is depressed and is called the throttle, while the second restricts the air supply when the chainsaw is cold-started. To make it easier to start, the choke is closed, which means that the mixture becomes rich because it is saturated with more fuel. It’s easier to work in this mode, but as it increases fuel consumption, this mode is not used during all work. The saw is working too hard.

In order to spray fuel into the cylinders, a nozzle with a check valve is used.

The principle of operation is simple: it limits the return of the mixture back into the chamber. All the main malfunctions of chainsaws, most often manifested by the improper operation of this mechanism.

  • The most common mistake is storing the tool for too long. The fact is that with prolonged inactivity, the valve jams and either fills the cylinder with fuel, or simply does not open.
  • The second problem is increased air in the mixture caused by sucking in air from the outside if the valve does not work properly. It is no longer possible to regulate here, because in this case only the repair of the valve or its replacement will help, because the adjustment screws will not respond to the saw.

Unlike a car carburetor, the adjustment of a chainsaw carburetor involves three adjustment screws that are responsible for mixture quality, quantity and nominal revolutions of the Husqvarna engine crankshaft:

  • screw L. designed to adjust the number of revolutions when working in medium modes and regulates low revolutions;
  • H screw. adjusts the amount of high revs and thrust of the rig;
  • T. is intended for adjusting the total amount of fuel and adjusts the work of the throttle unit.
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It is not advisable to touch the first two screws without special skills. The problem is that if you adjust them incorrectly, the carburetor will not be able to ensure the start of the engine, or even start it in the wrong operating modes. Such adjustments can lead to early wear and tear of the propeller and cause it to fail. This principle is present in many devices.

No table at all indicates the parameter settings. It is therefore not worth looking up this data in specialised literature; just follow the instructions carefully. The table in the datasheet is for informational purposes only, and concerns engine performance.

Why you need to adjust your Husqvarna carburetor

The carburetor is one of the important mechanical assemblies that make up a chainsaw. Its tasks include mixing fuel with air and supplying the resulting composition to the engine. But in the process of work of a chainsaw there are situations when adjustment of the carburetor of Husqvarna becomes necessary. Depending on the cause, adjustment of the carburetor of the 142 Series and other chainsaw models is performed to prevent the following situations:

Since the carburetor affects the quality of fuel, in the first case, the need to adjust the carburetor saw 137 or other professional series, such as Husqvarna 240 or 260 involves influencing exactly the sufficient amount of fuel that enters the carburetor to mix with the air mass. It is known that the maximum performance is possible only with a certain ratio of these substances. The second point of adjustment of the carburetor chain saw mixer is caused by a lack of incoming air, which provokes underburning of the injected gasoline with its output in the form of thick smoke. Timely change of parameters with your own hands to reduce the amount of injected fuel will reduce the consumption of this product much faster.

Repair by your own forces will save not only the budget, but also the time spent on transportation and the turn in the shop. The same applies to the replacement of various spare parts in gasoline-driven tools, such as a chain on a chainsaw or a universal trimmer head on a brushcutter, or oil for electric drive products.

How does the carburetor on the Husqvarna 137 chain saw work??

At chainsaws of these models most often set from the factory carburetor Walbro. Before adjusting the Walbro carburetor on the Husqvarna chainsaw, it is necessary to have a minimal understanding of its construction and know the principle of operation.

What is responsible for the fuel and oil mixture

For a precise delivery of fuel with oil, the operation of the fuel pump, which is driven mechanically from the crankshaft. The carburetor itself is equipped with a diaphragm and a special needle valve, which are responsible for regulating pressure in the system. Thanks to them, the metering chambers and the pump are organized to work properly, which improves the performance of the chainsaw.

Preparation of fuel mixture

When operating the chainsaw, a fuel mixture of gasoline and oil in a ratio of 15:1 by volume should be used, t. е. add 1 liter of oil to 15 liters of gasoline and mix the mixture thoroughly. The amount of gasoline and oil in the fuel mixture is given in this table:

Gasoline.л 1 2 3 4 5 6 7 8 9 10
Oil, l 0.06 0.13 0.20 0,26 0,33 0.40 0.46 0.53 0.60 0,66
Fuel mixture, l 1.06 2,13 3,20 4,26 5,33 6.40 7.46 8.53 9.60 10.66

NOTE! Application of oils: “Lukonay-2T; TNK-2T OIL: AZMOL Sport 2T GD” and Dr., and used oil in the fuel mixture will cause the connecting rod needle bearing to fail.

What is responsible for the air supply

Two dampers on the diffuser chamber are responsible for the air supply. The first throttle valve can control the amount of airflow when the gas pedal is depressed, and the second throttle valve limits the airflow when the chainsaw is cold-started. In order to facilitate starting, the choke is closed, which means that the mixture becomes rich as it is saturated with more fuel. It is easier to work in this mode, but since it increases fuel consumption, this mode is not used during all work. The saw is working hard.

To atomize the fuel in the cylinders, a nozzle with a check valve is used.

The principle of operation is simple: it limits the return of the mixture back into the chamber. All of the major malfunctions of chainsaws, most often manifested by improper operation of this mechanism.

  • The most common mistake is to keep the tool for too long. The thing is that if the valve is idle for a long time, it jams and either floods the cylinder with fuel or simply does not open.
  • The second problem is an increase in the amount of air in the mixture, caused by its suction from the outside, if the valve does not work properly. Here you can not adjust, because in this case, only the valve repair or replacement helps, because the adjustment screws will not respond to the saw.

Unlike a car carburetor, the adjustment of a chainsaw carburetor involves three adjustment screws that are responsible for mixture quality, quantity and nominal revolutions of the Husqvarna engine crankshaft:

  • L screw. designed to adjust the amount of rpm for medium-duty operation and adjusts the low rpm;
  • Screw H. adjusts the number of high revolutions and the thrust of the unit;
  • T. designed to adjust the total amount of fuel and adjusts the operation of the throttle assembly.
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It is not recommended to touch the first two screws without special skills. The problem is that if you set them up incorrectly, the carburetor won’t be able to start the motor, or even start it in the wrong modes of operation. This adjustment of the propeller can lead to premature wear and failure. This principle is found in many machines.

Settings are not listed in any of the tables. So don’t look up this information in specialised literature, just follow the instructions carefully. The table in the datasheet is for informational purposes only, concerning the characteristics of the engine.

How to adjust the carburetor on a Husqvarna chain saw (Husqvarna); tuning and adjusting the saw

The company called Husqvarna was founded in 1687. “Husqvarna” (Husqvarna) is the market leader in production and garden equipment. Part of a Swedish group of companies. Producing various types of equipment, from compact sewing machines to impressive ATVs.

Husqvarna” offers its customers the widest range of specialized machinery and equipment. In recent years the company has increased the number of patented innovations. “Husqvarna” is firmly on the lookout for progress.

Its products make hard work a breeze (see brand-name chainsaws and pruners). As a sawmill it is very simple and safe to cut wood with a chainsaw, not harmful to the human body or environment.

Husqvarna 137 chain saw belongs to the category “forest professionals. Along with this model the manufacturer also produces multi-purpose professional chainsaws, blowers and pruners. All its products are characterized by their compact size and ease of operation. All Husqvarna chainsaws offer three features. the ability to absorb excessive vibration, an advanced air filtration system, and high power output.

When you need to adjust the carburetor on a Husqvarna chainsaw

Neglecting deviations in the normal operation of gasoline tool is fraught with the fact that even with a strong desire to regulate the carburetor chain saw Husqvarna may be useless, and will require replacement of this unit, or already elements of the engine, affected by prolonged thermal or mechanical stress. Therefore, as soon as the saw shows the first deviations, it is necessary to make the repairs immediately in the form of simple adjustments. Among such changes in the operation are the following:

  • The chainsaw accelerates too slowly;
  • The tool does not reach its maximum power, and when loaded, it drops quickly;
  • The motor frequently stalls;
  • A loud noise is heard during the chainsaw operation;
  • The chainsaw emits an uncharacteristic amount of smoke that increases with every load step.

As soon as you notice any of the above abnormalities, the carburetor of the grass saw 435 or its slightly reinforced copy of the Husqvarna 55 saw should be urgently adjusted. Timely maintenance also means no expenses for a complete replacement of parts and units of drive and fuel system of chainsaw engine. Therefore, in case of difficulties with carburetor system Husqvarna 340 and all other lines of adjustment will save both chainsaw and working processes and the owners’ money. If necessary, the company grass trimmer-motors can be ordered insist mechanisms, replacement parts, as well as to buy a line for the grass trimmer with advice on how to install it yourself.

Adjusting the Husqvarna carburetor with your hands

In all Husqvarna gasoline saws the carburetor adjustment is performed in a similar manner, since all products have the same set of mechanisms. For example, if the adjustment of systems in the series 236 gasoline power tools, the process is accompanied by finding the highest idle speed by slowly turning the adjusting screws L. affecting the nozzle at low speeds, T. the nozzle at high speed and H. idle speed adjustment. The process of adjusting by hand consists of several periods, involving the rotation of the L and H screws that control the throttle of the fuel mixture and the adjustment of the T screw, which adjusts the idle speed. Depending on the parameter to be adjusted, the saw is adjusted in the following sequence:

  • After warming up, turn the L screw to the highest idle speed. As soon as these are found, you should turn the screw downward by ¼ turn. If the chain starts to rotate, make the accompanying adjustment of the T screw against the clock until the chain stops.
  • Adjustment of the H screw on the carburetor of the chainsaw takes place on the 10-second period of the engine at full throttle, spending ¼ of a turn. If the maximum load is not reached, the operation is repeated. Insufficient adjustment will be accompanied by a squealing saw, while exaggerated settings will cause the muffler to blow more smoke.
  • Adjusting the T of the idle speed screw is done by revolving the clock until the chain starts to turn. Once this has happened, the screw is tightened back until the mechanism stops.

Of course, making carburetor adjustments will allow your tool to perform at its best, but don’t forget about lubrication. Grasshopper Motors recommends buying special purpose chainsaw oil for the mechanisms, as timely maintenance will give the tool an additional period of quality service.

Modern chainsaws have a complex system and consist of several major components, which periodically require maintenance and adjustment. In this article we will talk about how to adjust the carburetor on a Husqvarna chainsaw.

Checking and Adjusting the Carburetor

At service centers, carburetor adjustments are made on special equipment. The angle of the adjusting screws is different for each saw (these are listed in the instruction manual). The need to adjust the carburetor does not arise very often, especially if the saw was purchased from a trusted seller. All of our Husqvarna saws are sent to the service center for adjustment of throttle speed before sale.

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However, misalignment of the adjusting screws sometimes occurs.

Causes of the chainsaw carburetor adjustment failure:

  • Severe engine (piston) wear and tear. In this case it is necessary to take more care about repairing the engine, but adjusting the carburettor can improve the function of the saw for a short time.
  • Clogging of the carburettor due to a damaged air filter, use of poor quality gasoline and scale formation.In such a situation, in addition to adjusting the carburetor, you will also need to flush it.
  • Severe vibration of the saw or damage to the blade guard. It happens very rarely, but there are still cases.

Signs that indicate the need to adjust the chainsaw carburetor:

  • The engine either does not start or starts and immediately stops. This is due to the use of a bad fuel mixture.
  • Significant increase in fuel consumption and increased emissions. An increase in the amount of exhaust gases indicates that the fuel is not burning completely. This may be caused by oversaturation of the fuel.

Регулировка карбюратора на бензопилу Хускварна 142

The scheme of carburetor adjustment for different chainsaw models differs and is described in the instruction manual. However, the general principle remains the same: you need to change the amount and quality of the fuel mixture fed into the engine cylinder.

Adjust the carburetor will help us three screws:

  • “L”. low, to adjust the low rpm
  • “H”. high, for the upper rpm setting
  • “T” (“LA”, “S”). for adjusting the idle speed (models that have only one screw have exactly the “T” screw)

When adjusting the carburetor of a chainsaw the following rules should be observed:

  • Make sure the saw chain is pointing away from you
  • Place the saw on a stable, level surface; the cutting part should not touch any objects.

Note: the instructions show the exact angles of rotation of the adjusting screws. If you follow the instructions carefully you can avoid damaging the engine.

The actual carburetor adjustment process involves two steps: a basic adjustment (with the engine stopped) and a final adjustment (with the engine warmed up).

Husqvarna chain saw carb adjustment

The Constructive Parts of a Chainsaw

All chainsaws are similar in structure, whether they are made in Europe (Echo, STIHL, Husqvarna) or at home (Cedar, Urals) The main elements are located inside the body. Fuel tank and engine, and outside. Starter, handle, part of the saw (guide bar) with chain. A sharp jerk of the cable starts the engine and this is the saw blade.

First we suggest that you read the video clips which show you how the chainsaw is built and how it works:

From time to time malfunctions occur in the saws that require disassembly. What can happen to something as simple as a chainsaw? At least the following:

Most problems are due to engine failures (fuel system, exhaust system, ignition, part of the cylinder with piston) or failures of other systems and components (clutch, chain brake, tire, lubrication system). Let’s look at the most common malfunctions and how to fix them.

How To Adjust / Tune a Chainsaw Carburetor | Husqvarna Stihl BEST Way

Working chainsaw starts with one jerk and fails to cut

How a chainsaw carburetor works?

The main purpose of a carburetor is to mix the fuel and air in the right proportions. If the latter are disturbed, it has an almost instantaneous effect on engine performance.

STIHL MS 181 C BE chain saw carburetor

Chainsaw carburetors may differ in design. Their basic elements and principle of operation, however, remain more or less the same.

This is a wind tunnel with an air inlet across which the airflow rate is controlled.

This part is where the base tube is drained. here the airflow rate increases, i.e.е. the air is always supplied to the carburetor under some pressure.

At this point the fuel is in contact with the air flow. Fuel enters the atomizer from the float chamber through the nozzle (dispenser).

It is a tank that keeps the fuel mixture in a stable state.

Constructional diagram of a chainsaw carburetor

The chainsaw carburetor works according to the following principle:

  • when starting the engine, the main flap opens and a stream of air flows into the air duct at a certain speed;
  • the speed of the air flow, as well as the float level in the chamber are regulated by the position of the flapper, namely by the pressure difference in the float chamber and the air duct;
  • Fuel from the float chamber is sucked into the jets, and from there into the diffuser;
  • Passing through the diffuser, the air traps the fuel that enters the diffuser;
  • The resulting mixture is fed into the cylinder cavities through the intake air ducts.

the pressure in the float chamber is approximately equal to atmospheric pressure, but in the air ducts of the carburetor when starting the chainsaw engine there is a vacuum. Opening the damper increases the airflow rate. As a result, more fuel goes into the carburetor and the engine rpm goes up.

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