Husqvarna Chainsaw Carburetor Adjustment

Scope of application

Husqvarna Chainsaw Carburetor Adjustment

The device is suitable for sawing everything except metal nails and earth. Its technical characteristics allow you to expand the scope of application to almost professional level.

The tool is used for:

  • Preparation of firewood;
  • Preparation and dismantling of construction timber;
  • Formative and sanitary pruning of fruit trees;
  • Production of designer wooden parts for interior landscaping.

Husqvarna 137 easily cuts hard trees with trunks up to 30 cm, copes with standard, diagonal, single-start and longitudinal threads. And its compactness allows you to work even in hard-to-reach places.

over, during the sawing process, fatigue is felt after a long time, which is due to the high center of gravity of the saw, its narrowed configuration and flat body bottom.

Carburetor

This part ensures the formation of a combustible mixture and its metered intake into the engine combustion chamber. In chainsaws, carburetors are characterized by a distance between the centers of the fastening holes within 31 mm.

For Husqvarna 137, Walbro brand accessories with device type WT-660 are ideal.

According to experts, the Husqvarna H30 chain is ideal for this model of chainsaws, which is characterized by a step length of 8.25 mm, a thickness of 1.3 mm and provides 64 links. During operation, it moves at a speed of 16.3 m / s.

For the best tool performance, the manufacturer advises sharpening the chain from specialists. But the level of its tension can be determined independently. Its adjustment is carried out with a screwdriver. To do this, turn the adjusting screw a quarter of a turn to the right or left.

Saw device

If you disassemble the saw body “Husqvarna 137”, then among its components you can find classic elements of mechanical engineering and the latest technological developments.

The structure consists of:

  • Cylinder with a piston engine;
  • Clutch;
  • Starter;
  • Front and rear starter handles;
  • Chain brake and its handles;
  • Fuel and oil tanks;
  • Muffler;
  • Tires with a guide gear;
  • Chains that are activated using a tension screw;
  • Protective cover for the right hand;
  • Ignition switch;
  • Throttle and its locking lever;
  • Air damper regulator.

Outwardly, this is a block inside which there is a two-stroke internal combustion engine with the necessary containers for fuel and lubricating fluids.

Of all the components, the tire and the cutting chain are included in the number of replacement parts. As their resource is depleted, it is necessary to timely replace this equipment. This can be done using spare parts of analog or other brands with the appropriate length.

The process of replacing worn out components is simple, but at home it requires the use of a set of factory keys.

Chainsaw “Husqvarna 137”: how to disassemble and assemble, how to adjust the carburetor

Small-sized chainsaw “Husqvarna 137” is characterized by good quality, maintainability and durability. This solid machine is ideal for non-professional needs.

What features this model has, what should the owners take into account when disassembling and assembling it, as well as the intricacies of adjusting the carburetor, we will discuss further in the article.

How to disassemble and assemble the Husqvarna 137 chainsaw

Dismantling the body of a chain chainsaw is carried out in order to replace the cylinder and piston system. To do this, loosen all the bolts and remove in turn.

Now it’s time to install the new piston and crankshaft. To do this, press in the drive gear of the oil pump and put on new bearings on both sides. The oil seal will be located on the left. The piston is mounted on the connecting rod in a specific position. This is indicated by an arrow on the top of it. After disassembling the structure, it should return to its original position and point to the muffler. In our case, on the left is a tapered seat for the flywheel and part of the crankshaft, and on the right is the drive gear of the oil pump. So the arrow must point north.

Further, a retaining ring can be inserted into one of the gears. A piston pin is inserted into the opposite one. And only after these manipulations, the piston is put on the upper head of the connecting rod. Now you need to push the piston pin and, on the other side, install the retaining ring on it. At this stage, the assembly of the crankshaft and piston is complete.

The following actions should be aimed at sealing the planes, the contact of the cylinder with its bottom cover. For these purposes, the usual automobile sealant “Abra” or silicone “Hermesil” is used. The product is applied in a thin layer (no more than 1 mm) to the edge of the lid, after which the part must be set aside to dry for 5-7 minutes.

In the meantime, we are starting to assemble the chainsaw engine. Please note: the lock of the compression ring is at the level of the pressed-in pin. It is important to avoid confusion at this point and to insert the piston correctly. This is done carefully, without unnecessary movements and efforts. The part should fit easily inside.

Then we attach the cover greased with sealant on top and screw it with bolts.

Be sure to check that the applied agent comes out of the joint on all sides. Turn the crankshaft by hand. It should rotate easily.

Then we proceed to mount the engine on the crankcase of the chainsaw, screwing it from below with 4 bolts.

We install the resulting structure on the base of the saw, shift the holes and fix the parts with screws.

If 2 rubber buffers fell out of the device during disassembly, return them to their place.

After that, lower the crankcase and insert the gas line into its hole.

At the same time, it is important to keep the channel in a taut position, otherwise bends may appear on it.

Now the turn has come for the decorative attachment, which needs to be fixed with 1 screw.

Then we assemble the oil pump in the reverse order of disassembly and fix it with 2 self-tapping screws.

The next step is to install the clutch, washer and drum, which must first be lightly greased with oil.

After it, weights are put on the structure.

Put on the cylinder 2 pipes, and then install the carburetor adapter.

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This is done in such a way that the large oval hole goes into the black tube, and the second, small one, into the seal pipe of the impulsive channel.

We proceed with the installation of the ignition module on the cylinder and screw it.

Do not forget to put a terminal under the lower screw to ensure power supply.

For convenience, you can move the low-voltage wires into the carburetor compartment so as not to touch them during further work.

We mount a flywheel on the engine. There is a groove on the seating surface, and there is a kind of key on the flywheel body.

Please note that on modern gas powered tools, the magneto is installed in only one position using a veneer connection. Adjustment of this mechanism is not provided.

When the flywheel is turned clockwise, upward movement of the piston is visible in the exhaust port.

Exhaust gas outlet

As soon as it covers this “window”, load the rope through the candle hole.

Rope with knots

Stretch the flywheel and clutch with a 17.

During the operation of the chainsaw, the magneto tightening level will independently adjust. The rope can now be removed.

Next, adjust the gap between the ignition module and the flywheel. To this end, we turn the crankshaft, after which we bring the flywheel and ignition magnetic lines under each other. Place a probe in the resulting space.

Its role is played by an ordinary aluminum strip from a beer can. The cut piece is bent in half so that the material thickness does not exceed 0.2 mm.

In this position, tighten all available screws and remove the lining.

Loosen the screws of the ignition coil, after which it will be pulled to the flywheel, clamp them. The required clearance is set

Now we collect the muffler. For this purpose, we initially install its back, the gasket, then the screen.

It is characteristic that all these components are attached with a single small bolt. Therefore, for convenience, screw them in with 2 large screws.

Install the air duct and its drum, then install the starter cover.

If the components do not fit into their natural position, extend the cable.

At the final stage, tighten the bolts.

Place a pad on the right under the tire, straightening its bent tendril if necessary.

Next, in the carburetor compartment, we mount the ignition switch, putting one of the wires on its contact.

We put on the carburetor, and on top of its fitting on the adapter we attach the gas line.

Installing the air damper.

We mount the metal rack for the carburetor and screw it.

Twisting one of the lower self-tapping screws, place a low-voltage wire terminal under it.

Then install the throttle rod.

The turn has come to install the air filter and its housing.

Please note that the rubber covers on the bolts are put on when the filter is removed after adjusting the carburetor.

Now you can put on the cover on the chainsaw, securing it with 3 screws.

Do not forget to screw on the cross handle, placing a rubber buffer between the joint parts.

After the work done, you should have 4 self-tapping screws: the short ones twist from the bottom, and the long ones. From the side.

About Husqvarna

The trademark of the Swedish industrial company Husqvarna has been known to consumers for over 300 years. The company was founded in 1689 in the city of Husqvarna, initially positioned as an arms factory.

But even on this, the achievements of the oldest European company did not exhaust themselves. Among her latest developments is the line of robotic cordless mowers from the Automower brand.

How to properly adjust the carburetor on a chainsaw with your own hands?

A chainsaw is a useful, and sometimes simply necessary tool for the owner of a private house. It has a high degree of autonomy, can be used in the field, where there is no possibility of connecting to the power supply network. For some craftsmen, the chainsaw is one of the main devices that perform large amounts of work almost daily. Such loads knock down the factory settings that were set for all important engine components.

The operating mode most often changes with the carburetor, which has to be re-adjusted. Without understanding the design and principle of operation of this element, it is impossible to properly adjust it. The question concerns many users who operate chainsaws tightly, so it will be useful to consider it more carefully.

  1. Design and working principle
  2. When is carburetor adjustment necessary?
  3. Adjustment tools
  4. How to properly adjust the carburetor with your own hands?
  5. How to set up a China-made saw?

When is carburetor adjustment necessary?

Initially, from the moment the tool was sold, all carburettors were adjusted and tuned at the factory. However, in the process of operation, the settings gradually go astray, and the operating mode changes in accordance with the operating conditions. Signs of a carburetor malfunction may include:

  • Too high gasoline consumption, thick smoke comes from the exhaust pipe;
  • Engine power is clearly not enough to perform normal tasks;
  • Engine speed “float”;
  • After starting, the motor stalls either immediately or after a few seconds;
  • The engine cannot be started at all;
  • The chainsaw “shoots”, there are sharp claps in the tool engine.

It should be noted that during the running-in of a new engine, the carburetor is set to a reduced fuel supply in order to limit the engine power. After the end of the run-in, the fuel supply increases to the nominal value. These adjustments are made using the adjusting screws on the carburetor body (usually two or three).

Adjustment tools

To tune the carburetor, you will need a Phillips or slotted screwdriver of different lengths or thicknesses; the size depends on the design of this unit and the features of the engine assembly. It should be noted that some manufacturers make carburetors designed to use special tools.

In particular, special types of screwdrivers may be required to adjust Husqvarna carburettors and other imported tools. It is advisable to clarify this question even when buying a chainsaw, so that you can purchase the necessary additional equipment in advance.

In addition, you will need refined gasoline or acetone to flush and clean the device. They are used to clean the outer surfaces of the carburetor. All internal channels are flushed with kerosene, diesel fuel or white spirit. Before flushing, the carburetor is disassembled, all rubber or plastic parts that may suffer from contact with aggressive chemical compounds are removed.

Open-end or spanner wrenches are used to disassemble the carburetor. Internal canals are washed in specially designated trays, sometimes plastic syringes are used for this.

Design and working principle

A carburetor is a device that mixes fuel (gasoline) and air in specified 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.

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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;
  • Diffuser with an air damper, which are located at the entrance;
  • Jets, which are valves for metering fuel supply;
  • Spray, providing injection of 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 the carburetor can be described as a cycle consisting of the following steps:

  1. Air damper opens during engine start.
  2. 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.
  3. Gasoline flows from the gas tank to the float (fuel) chamber. The rate of its admission is regulated by jets.
  4. Gasoline and air are mixed in the diffuser, which results 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.

How to properly adjust the carburetor with your own hands?

After rinsing and completely cleaning the carburetor, assemble it and begin to adjust. First of all, you should understand the purpose of the adjusting screws. The instruction will help with this, but some general points should be considered right away. The most common designations for screws are:

  • H. Adjusts the state of the main jet, i.E. Adjusts the maximum speed of rotation of the motor shaft;
  • L. Adjusts the idle jets (responsible for the minimum shaft rotation speed);
  • T. Regulates the engine idling. It can also be designated by the letters LA or S, on some models of carburetors it is not at all.

Turning screws H and L clockwise depletes the air-fuel mixture, and counterclockwise enriches it (the amount of gasoline increases). When the screw T rotates, the idling speed of the shaft changes. It increases clockwise, and decreases in the opposite direction.

Figure 2. Carburetor adjustment mechanisms

Before proceeding with direct actions, you should find and carefully study the information on the position of the adjusting screws (the magnitude of the angles of rotation during adjustment). This information is available in the instructions for the chainsaw. Then you need to prepare the workplace. Lay the saw on a flat horizontal plane, directing the chain in the opposite direction from you. Detach all covers, remove foam rubber and air filter. At this, the preparatory operations are considered completed, you can proceed to the main part of the work.

Carburetor adjustment procedure:

  1. Smoothly tighten the screws H and L clockwise until they stop. Be careful not to break the screws. This will cause a complete loss of the carburetor.
  2. Unscrew both screws one and a half turn.
  3. Run the engine for 10 minutes and warm it up. This is a necessary moment, since it will not be possible to correctly adjust the carburetor on a cold engine.
  4. Turning screws H and L, alternately adjust the rotation of the shaft at maximum and minimum revolutions.
  5. By adjusting the position of the screw T (or it may have another designation), the idle speed of the chainsaw is adjusted. It is necessary to achieve smooth and stable engine operation. It is important to monitor whether the chain is idling or not. If it moves, turn the screw a little more counterclockwise.

You can check the operation of the engine visually and by ear. Too rich mixture will cause thick smoke from the exhaust. When the lean mixture is being fed, a whistling sound is heard while the saw is running. Excessive economy mode is harmful. If the L screw is set to “lean” fuel, there will be problems with starting the engine. If the H screw is set to lean, the saw will noticeably lose power. You can determine the correct setting by the following criteria:

  • At idle speed, the engine does not stall, and the chain is stationary;
  • There is no excessive smoke from the exhaust pipe while the engine is running;
  • The engine demonstrates good throttle response (quickly picks up speed when you press the accelerator).

A detailed description of the setting is available in the instructions that come with the instrument in the delivery set. It should be carefully studied, as there may be some features or specific requirements set by the manufacturer and related only to this saw model. If all requirements are met exactly, the performance of the chainsaw will be restored to its original state.

How to set up a China-made saw?

The design of the carburetor on Chinese chainsaws is no different in principle. The order and principle of adjustment also do not differ and are performed in the same order. The only difficulty that may arise during work is determining the purpose of the adjusting screws. Typically the T screw is on the top and the H and L are on the bottom of the carburetor body. One additional screw may be present.

Figure 3. Location of adjusting mechanisms

Usually, their purpose is determined empirically, slightly changing the position and monitoring the result. After the purpose of the elements is clearly defined, further customization is not difficult and is carried out in the usual way.

Chainsaw carburetor tuning is an important and necessary procedure that must be periodically performed to restore the normal operation of the tool. This process does not create fundamental complexity, but it requires the user to be careful, attentive and comply with safety rules. The chainsaw chain is usually not removed, since you will need to observe its position. Therefore, it is important to constantly remember about the possibility of launching it and exercise the necessary caution.

The adjustment should be done smoothly, with small changes in the position of the screws, so as not to cause too sharp changes in the shaft rotation mode. The result depends on the care and thoroughness of the user, and a properly tuned carburetor will extend the life of the tool.

Ignition adjustment after carburetor adjustment

If cleaning and adjusting the carburetor did not correct the existing problem, you need to check the spark plug and tune the engine. It is worth acting in the following order:

  1. A candle is unscrewed and a visual inspection is carried out. If it is dry with a light brown carbon deposit, it can be considered intact.
  2. If traces of gasoline are found on the spark plug, the carburetor should be readjusted. This is because it supplies an excess amount of fuel to the internal combustion engine, filling it.
  3. If the candle looks normal, check the electrical equipment. First of all, the cable that supplies current to the candle. The end of it is brought a short distance to the radiator grille of the cylinder and the starter is turned with a cord. A spark should slip through. If not, the cable is checked with a tester and, if necessary, replaced.
  4. If the cable is in good condition, the ignition coil is tested. If the inspection does not reveal singed or broken wires, the coil is called with a tester, comparing the data with the accompanying documentation. If deviations are found, the block must be replaced with a similar one.
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After replacing the coil unit, the magneto gap should be set. The gap between the ignition coil and the flywheel should be between 0.2 and 0.4 mm. To set the gap, you need a set of probes, or you can use foil of a suitable thickness. The probe is clamped between the coil and the flywheel at the time of installation, and then pulled out.

How to adjust correctly

For this, the device has 3 adjusting nozzles. The idle speed screw (T) is located at the top of the carburetor. Below there is a pair of jets for adjusting the fuel supply at minimum (L) and maximum (H) rpm, left and right, respectively.

The procedure for adjusting the carburetor on a Husqvarna chainsaw is as follows:

  1. Warm up for 5 minutes.
  2. Turning screw L, we bring the engine to the highest speed in an unloaded state and return it back a quarter of a turn.
  3. Hold the gas button with one hand for 15 seconds. At this time, we turn the H jet to the right until it stops and reaching the maximum speed. Then we turn it back one and a half turns, or until the “squeal” of the engine disappears.
  4. With the throttle released, turn the idle screw (T) clockwise until the chain starts to move. After that, we rotate it in the opposite direction until the chain stops moving.

During the adjustment process, a situation may arise in which the chainsaw stalls. This may be due to excessively twisted jets, too rich or poor mixture.

If this happens, it is necessary to tighten the jets of the minimum and maximum speed until they stop. Then turn them back one and a half turns and try to start the saw.

When adjustment is needed

The need to adjust the carburetor of a chainsaw is rare. often there are problems with the flow of fuel, air or wear of parts. But sometimes adjustment is still required:

  • A running engine stalls after a few seconds, or it does not start. The reason for this is a too rich mixture;
  • Excessive exhaust, high revs, increased consumption. In this case, on the contrary, the mixture is too lean, i.E. There is not enough air;
  • RPM is kept at the same level after its decrease or increase by the operator. The cause may be a stuck needle valve.

The factors leading to such changes can be the following:

  1. Strong vibration damages the protective cover and the adjusting jets are unscrewed, changing the setting. In this case, it is possible to adjust the carburetor on the chainsaw.
  2. Wear of elements of the piston system. Adjusting the carburetor in such a situation can be of temporary help. Replacement of worn out components is recommended.
  3. Poor quality fuel, faulty filter, or long storage can cause blockages. In this situation, the carburetor must be removed, washed with a special liquid or clean gasoline, assembled and re-adjusted.

It is best to start tuning the saw by checking the jets, fuel and air supply. After that, proceed to dismantle the carburetor, and then. To check the piston system.

What tool is required

First of all, you need to prepare a tool for adjusting the chainsaw carburetor. You will need a set of screwdrivers and open-end wrenches, a special cleaning compound that dissolves carbon and debris.

Disassembly is best done on a table or workbench. On a part of the table, lay a flap of clean, preferably light and monochromatic fabric, on which the parts to be removed and a container for washing will be laid out. It is optimal if it is an ultrasonic bath.

How to properly adjust the carburetor of a Husqvarna chainsaw with your own hands

The chainsaw is an indispensable tool for people living in private households. It is a mechanism consisting of carefully fitted parts and assemblies.

Like any mechanism, it requires periodic maintenance and adjustment. Especially because of low-quality fuel. Consider the principles and procedure for adjusting the carburetor of a Husqvarna chainsaw.

The device and principle of operation of the carburetor

The carburetor is used to prepare a combustible mixture in a ratio determined by the operator from gasoline and air.

The correct functioning of the device depends on the correct setting and adjustment.

And for this you need to know the principles of operation of the carburetor of the Husqvarna chainsaw.

Its design consists of the following elements:

  • Body with clamping bolts and a set of gaskets;
  • Fuel pump. A device that pumps a gasoline-oil mixture into the carburetor;
  • Diaphragm. Designed to limit the supply of a combustible mixture to the engine;
  • Float chamber. Fuel is collected in it, the level is regulated by the float, as required, the mixture is fed into the main chamber for mixing with air;
  • The main chamber. Air passes through it, and fuel is injected there, the amount of the mixture supplied to the engine is regulated by the throttle valve located here;
  • Diffuser. Section of narrowing of the air supply tube at the place of fuel injection;
  • Needle valve. A device that regulates the fuel supply;
  • Jet. Screws that regulate the mixture supply at high and low speeds, as well as an idle screw.

Also in the carburetor device, in addition to the throttle, there is a damper located at the inlet from the air filter. It artificially reduces the air supply, making the mixture richer for easier cold starting.

The injector valve is responsible for fuel injection into the main chamber, it also prevents air from entering. When adjusting the carburetor on a Husqvarna chainsaw, special attention should be paid to this valve, since its condition has a direct impact on engine performance. If stored for a long time, the nozzle may stick. This will restrict fuel flow and prevent the engine from starting.

Also, from prolonged use or due to a factory defect, the valve can let air into the main chamber. In this case, only replacing it will help fix the problem.

The carburetor works as follows: the air flow, entering the diffuser, mixes with the injected fuel, the resulting mixture is fed into the engine. The amount of the mixture is regulated by the throttle valve. The more mixture, the higher the engine speed.