Do-it-yourself Husqvarna 142 carburetor adjustment

Chainsaw Husqvarna 142. features of operation and maintenance

The Husqvarna 142 chainsaw is used for work in the garden and at the summer cottage, it is an excellent option for both felling trees and harvesting firewood. The Husqvarna 142 chainsaw has been designed with specifications for maximum productivity and safety. The engine speed reaches nine thousand units per minute. The size of the cylinder is nominal 40.2 cm³. The fuel tank is 410 ml and the oil tank is 200 ml. It should be borne in mind that the noise level is 118 dB. The unit weighs 4.6 kilograms. Tire length from 33 to 38 centimeters, chain pitch. 0.83 centimeters.

Carburettor adjustment or repair work on Husqvarna chainsaws can be done without any prior experience. In order to do everything right, you must follow the algorithm and have a minimum set of tools. It is also worth assessing your strengths in advance and not taking risks if you do not understand anything at all in the technique. Believe me, sometimes it is better to pay a small amount to the master than to ruin the instrument by self-adjustment.

Chainsaw Husqvarna 137 (Husqvarna) refers to amateur non-professional options. Low weight (4.6 kg without chain and bar) and engine power (1.6 kW) made it highly popular with consumers. There are 2 tire options available for this model, 13 “and 15”. Their pitch is 0.325 ″ and the maximum end radius is 10T. With proper operation and timely maintenance, it will last for many years. During operation, the device emits a noise of 98-108 dB.

Methods of work

Adjustment of the Husqvarna carburetor is made with screws L and H, if gasoline is used in the work, which differs from that recommended by the supplier. If the octane number is low, turn the screw by unscrewing it to increase it. This will increase the revs and power. But with an increased octane number, to lower it, turn the screw in the opposite direction by tightening it. This will help reduce engine speed.

When adjusting the Husqvarna carburetor, use the screws in the following order: L. H. T. Observing the exact angles of rotation, you will follow the requirements that will allow you to maintain the best operating parameters of the engine. There is no universal adjustment method. The procedures may differ from one another. But the process is usually divided into two stages. The first is basic, the second is final. The basic one is performed with the engine off, while the final stage provides for warming up the engine for 10 minutes.

Algorithm and description of setting the carburetor Husqvarna

Husqvarna carburetor, adjustable in the same way as carburetor settings on other brands of chainsaws.

  • Saw muffled with Husqvarna carburetor factory setting.
  • The engine starts and the saw warms up for a few minutes.
  • By turning the screw (L) clockwise, the position is found at which the engine develops maximum speed, after which the screw must be unscrewed 1⁄4 back. If at the same time the chain of the chainsaw rotates, then it is necessary to reduce the idle speed by adjusting the position of the screw (T).
  • The next stage is adjusting the power of Husqvarna at maximum speed and adjusting their number. To do this, the tachometer is connected to a running chainsaw, the throttle stick is squeezed out to full, after which the tachometer readings are checked. If the value of the maximum speed 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.

Design and principle of operation

A carburetor is a device in which fuel (gasoline) and air are mixed in predetermined proportions, followed by feeding the prepared mixture into the engine cylinder. Almost all models of chainsaws are equipped with carburetors of the same type, so the device and principle of operation are the same.

The main structural elements of the carburetor are:

  • body, which is cast from aluminum to reduce weight. Chainsaws constantly have to be moved from place to place, during operation they are held by hands, therefore, reducing the weight of the tool is the primary task of manufacturers;
  • a diffuser with an air damper, which are located at the inlet;
  • jets, which are valves for metering fuel;
  • a sprayer that injects gasoline into the chamber (in the diagrams it is designated as the main jet);
  • fuel (float) chamber.

Figure 1. Diagram of a chainsaw carburetor The principle of operation of the carburetor can be described as a cycle consisting of the following actions:

Homemade 136 Husqvarna fuel adjustment tool

  • When starting the engine, the choke opens.
  • The piston stroke creates a vacuum in the air channel, as a result of which air enters the diffuser, the amount of which is regulated by the position of the air damper.
  • Gasoline flows from the gas tank to the float (fuel) chamber. The rate of its admission is regulated by jets.
  • In the diffuser, gasoline and air are mixed, resulting in the formation of a fuel-air mixture, which then enters the engine cylinder. The more the mixture enters the combustion chamber of the cylinder, the higher the power and speed on the engine shaft will be.
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What is responsible for supplying a mixture of fuel and oil

For accurate delivery of fuel with oil, the operation of the fuel pump is used, which is mechanically driven from the crankshaft. 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, the correct operation of the metering chambers and the pump is organized, which improves the operation of the chainsaw.

Do-it-yourself chainsaw carburetor adjustment

A chainsaw is a tool that will come in handy in any summer cottage, even for amateurs, not to mention professional workers. But, like any other device, a chainsaw needs constant care and prevention. One of the most common procedures is adjusting the carburetor of a chainsaw due to a past misalignment.

Adjusting and tuning the carburetor Husqvarna 137

In the picture above, you see three adjustment screws. Each of them has its own purpose:

The T screw is needed to adjust the idle speed.

Screw L serves to adjust low rpm.

At first, with the L screw (rotating it), we are looking for the highest idle speed. After we have found them, we need to turn this screw a quarter of a turn against the clock hand. If in this position the chain continues to rotate, then by turning the screw T we achieve its stop.

Then we warm up the engine at full speed in the region of 10-15 seconds and turn the screw H a quarter counterclockwise. We wait 10 seconds and listen. the engine should work like a 4-stroke in sound. If a screeching sound is heard, then the mixture is poor (unscrew the screw), if the enriched mixture smokes (tighten the screw).

After adjusting low and high speeds, we set the idle speed with screw T. This is done as follows:

2.Rotate the screw T clockwise until the chain starts to rotate.

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3.Rotate the screw in the other direction until the chain stops.

With a properly adjusted carburetor, your chainsaw rapidly picks up speed and sounds like a 4-stroke engine.

Remember that it takes a tachometer and experience to properly adjust your chainsaw carburetor. Husqvarna carburetor adjustment on Husqvarna 236/240 Husqvarna 240 and. Idling turns. Its adjustment is the carburetor adjustment of the Husqvarna chainsaw. Husqvarna chainsaw carburetor adjustment recommendations carburetor adjustment. 240. Therefore, it is better to contact a special service!

Algorithm and description of setting the carburetor Husqvarna

Husqvarna carburetor, adjustable in the same way as carburetor settings on other brands of chainsaws.

Immediately before adjusting, it is necessary to carry out a complete diagnosis of the saw and make sure that there is no obstruction of fuel supply and air leakage into the crankcase of the chainsaw. It is also necessary to make sure that the air filter is clean and, if necessary, replace it with a new one.

  • Saw muffled with Husqvarna carburetor factory setting.
  • The engine starts and the saw warms up for a few minutes.
  • By turning the screw (L) clockwise, the position is found at which the engine develops maximum speed, after which the screw must be unscrewed 1⁄4 back. If at the same time the chain of the chainsaw rotates, then it is necessary to reduce the idle speed by adjusting the position of the screw (T).
  • The next stage is adjusting the power of Husqvarna at maximum speed and adjusting their number. To do this, the tachometer is connected to a running chainsaw, the throttle stick is squeezed out to full, after which the tachometer readings are checked. If the value of the maximum speed 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.

Saws STIHL & Partner

In STIHL 250, 361 and Partner 351, 350 chainsaws, the carburetor is adjusted using the H and L screws by setting the proportions of gasoline and air. If you release them, a large part of the fuel will be added and therefore the revolutions will be high, otherwise, on the contrary, they will fall.

Idling speed in Partner chainsaws is regulated with a screw with the letter T, and in Calm, as a rule, you need to look for the aircraft marking. 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 greater than that of air, which does not correspond to the optimal parameters. But they must be saved during the first hours of operation during the running-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 the actions must be performed in the following sequence:

  • screw adjustment L;
  • then adjust the H jet;
  • after that, go to the idle speed setting using the T screw (if the STIHL chainsaw is LA).
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First, screw L must be turned in both directions in order to find the maximum engine speed. If that point is found, then turn the same screw by ¼, thereby slightly slowing down the speed. If at the same time the chain continues to move at idle, it is necessary to immediately turn the screw T (LA) until the chain stops completely.

After setting the maximum speed with screw H, you need to check the frequency with the tachometer. In the event that it does not correspond to those indicated in the service book, the setting must be repeated. When a lot of smoke comes out of the exhaust pipe at maximum speed, then the mixture is too rich in fuel, if noises are heard and the engine is very hot, then on the contrary, it is poor. Then you need to adjust the idle speed. With the correct setting, the engine should sound even at low speeds, while the chain should not move.

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 engine to work. If this ratio is violated, then the engine will not work clearly. When the mixture has a lot of gasoline, then in unprofessional terminology it is called saturated, and if, on the contrary, there is little, then it is 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 carburetor designs, but they are all identical in principle. The air moves through a special channel at a speed that can be adjusted by closing or opening the damper. Gasoline, in turn, enters the carburetor through the jets and mixes there with air, creating a special mixture that enters the engine.

The pressure in the float compartment of the carburetor, where the gasoline is before mixing, is close to atmospheric pressure. When you open the damper, the air becomes more, 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 how the carburetor works.

In order for the chainsaw to work smoothly and efficiently, and also at the same time there was no high fuel consumption, its carburetor must be adjusted accordingly. Before such work, you must first check the air and gasoline filter. If dirt is found on them, then they should be replaced.

Chainsaw tuning for most models, as a rule, is carried out using three screws. high and low speed and idle.

The following signs should indicate the correct setting:

  • The chain must not move when idling.
  • Motor runs smoothly.
  • At the start, there should also be no breaks in the work.

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

The structure and principle of operation of the Husqvarna carburetor

To successfully tune your Husqvarna chainsaw carburetor, you need to know how it works and how it works. In fact, everything is not as difficult as it seems at first glance.

do-it-yourself, husqvarna, carburetor, adjustment

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

One of the valves is designed to adjust the fuel supply to the cylinder when the gas is pressed, it is called the throttle, the second is responsible for limiting the air supply from the air filter to facilitate starting a cold Husqvarna chainsaw. At the moment when the operator cuts off the air supply to the carburetor with the help of 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.

In the operation of the Husqvarna carburetor, a nozzle valve is involved, which atomizes the fuel and prevents air from entering the main chamber. Often, problems with the operation of the saw can be caused by defects in this particular element. For example, a valve, if the chainsaw is not stored properly, may stick, the fuel supply will stop, which will make the engine impossible to operate. Also, irregularities in the operation of the injector 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, it will be necessary to repair or replace the unit.

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

  • screw (L). adjusts the amount of fuel in the low and medium speed mode;
  • (H). is 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 engine of the tool in idle mode.

Screws (L) and (H) cannot be adjusted without specific knowledge and experience. Improper adjustment of the quality and quantity of the fuel mixture can cause the engine to stop working or malfunction, leading to rapid wear or even seizure.

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Husqvarna chain saw carb adjustment

When and why to adjust

The procedure for adjusting the carburetor is usually carried out quite rarely. The highest quality and best option is the factory setting. However, if necessary, it can be done by adjusting the corresponding screws. A carburetor in a chainsaw is necessary to prepare an air-gasoline mixture, which must have a certain ratio of ingredients. If the balance is not observed, then the engine will malfunction.

A mixture that does not meet specifications may be oversaturated or depleted. In the first case, the amount of fuel is increased in relation to air, in the second there is more air than needed, and fuel. less. The article will consider the adjustment of the carburetor using the example of a Husqvarna 142 chainsaw.

The carburetor in the chainsaw is needed to mix and supply fuel to the engine’s combustion chamber. If the carburetor is adjusted correctly, the operation of the equipment will be reliable in all modes, and fuel consumption will be economical. In general, this rule applies to all internal combustion engines.

Specifications

In order to provide the described equipment with long-term operation, you need to know how to adjust the Husqvarna 142 carburetor with your own hands. This was discussed above. However, this is not the only thing that the future owner of such a device should know. Before purchasing such equipment, it is important to inquire about the technical characteristics. For example, assess whether a weight of 4.6 kg is okay for you. By the way, it is well balanced, so the saw fits comfortably in your hands.

The shape of the handles is ergonomic, which guarantees a secure grip during difficult work. There is a vibration protection system inside, and the work is not accompanied by too high a noise level. All this contributes to high labor productivity and the preservation of human performance during large-scale work.

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

Do-it-yourself adjustment of the “Husqvarna 142” carburetor is quite simple if you read the instructions. From it, you can also find out that the power of the device is 2.6 liters. sec., or 1.9 kW. The chain pitch is 0.325 inches. The number of links is 64.

The set comes with a chain with a thickness of 1.3 mm. The displacement of the engine is 40.2 cm 3. The length of the tire is 38 cm or 15 inches. The oil and fuel tanks hold 0.2 and 0.41 liters, respectively.

Methods of work

Adjustment of the Husqvarna carburetor is made with screws L and H, if gasoline is used in the work, which differs from that recommended by the supplier. If the octane number is low, turn the screw by unscrewing it to increase it. This will increase the revs and power. But with an increased octane number, to lower it, turn the screw in the opposite direction by tightening it. This will help reduce engine speed.

When adjusting the Husqvarna carburetor, use the screws in the following order: L. H. T. Observing the exact angles of rotation, you will follow the requirements that will allow you to maintain the best operating parameters of the engine. There is no universal adjustment method. The procedures may differ from one another. But the process is usually divided into two stages. The first is basic, the second. final. The basic one is performed with the engine off, while the final stage provides for warming up the engine for 10 minutes.

Consumer reviews

You can adjust your Husqvarna 142 chainsaw yourself. Consumers consider this feature a plus, as well as the fact that the crankshaft in the design is made of forged steel. The advantage should be considered and the fairly easy access to the air filter. The ignition system is durable and simple. The piston group has two compressor rings, which have an increased working life. The manufacturer emphasizes that they will be ready to last up to 5 years.

Consumers also love the chrome-plated, wear-resistant cylinder liners. You may not need to adjust your Husqvarna carburetor as the manufacturer claims it is the best in its class. The design is also good in that it provides for a built-in primer. It is a pump that gives the engine a quick start. This feature is independent of the ambient temperature.

Important for owners

The carburetor of the Husqvarna 142 saw is adjusted with a wrench, also called a screwdriver. Some manufacturers use proprietary keys. If you have such, you should try not to lose them, because it will be quite difficult to find them on sale.

Adjustment

Adjustment of the Husqvarna 142 carburetor should be carried out using a tachometer. You must be able to work with it. If experience permits, manipulations can be performed by ear, determining the limiting revolutions by sound. In other cases, a positive result may not be achieved. Adjustment of the Husqvarna 142 carburetor is carried out with one, two or three screws. You can distinguish them by designations.

Idling is adjusted with a screw under the letter T. You can adjust the minimum speed with screw L. While screw H is designed for maximum speed. You will see one idle screw and two others hidden behind the shroud. This version of the carburetor is explained by the fact that the manufacturer recommends the operator to adjust with only one idle screw, since otherwise the optimal settings are still set at the factory. But for some extreme modes, you can make adjustments.