How to adjust the idle speed on a Husqvarna chain saw

Adjusting the carburetor on a Husqvarna chainsaw

The company, called “Husqvarna” was founded in 1687. “Husqvarna is a market-favorite for production and gardening equipment. It is a Swedish concern, which unites several companies within itself. Producing various kinds of techniques, from small sewing machines to impressive quad bikes.

“Husqvarna offers its customers a very wide range of special equipment and machinery. In recent years the company has increased the number of patented innovations. “Husqvarna is firmly on the lookout for progress.

Manufactured products of the brand makes hard work as usual occupation, which is harmless neither to humans nor the environment.

adjust, idle, speed, husqvarna, chain

Husqvarna 137 chainsaw belongs to the category “Forest Professionals. Together with this model the manufacturer also produces multi-purpose chainsaws, blowers and pruners. All produced equipment is characterized by small size and ease of operation. All Husqvarna chain saws have three features. ability to absorb excessive vibrations, advanced air filtration system, highest power.

Features of Chinese chainsaw carburetors

Their design and parameters differ, depending on what power and model chainsaw they are designed for. All of them are almost identical to the original carburetors in design, but not always in quality. Today you can not consider all Chinese products 100% junk. In turn, in terms of quality, they can be divided into three groups conditionally:

  • Low-quality. Unsuitable alloys are used, which oxidize, crumble and break. No precision fit, calibrated holes are not as required, leading to fuel overruns or shortages in the combustion chamber. Critical components fail quickly. Plastic parts quickly become rough or vice versa, soften from gasoline and stop working. Axles and wire rods bend, fastener threads break. These products are the cheapest of all. They are made in semi-amateur productions, on adapted equipment. As a rule, they do not have names and markings.
  • Medium quality carburetors. These products are factory assembled. They do not skimp on alloys, running production with quality control. These are perfectly serviceable carburetors that can have a lifespan that is even longer than that of an entire chainsaw.
  • Quality carburetors. First of all, these products are products of world manufacturers, whose facilities are located in China. According to the geography they can be considered as Chinese, but made in accordance with the technology of the company. the brand owner, which values its reputation. For example, Japanese Walbro carburetors are made in the PRC.

In addition, among Chinese manufacturers appeared those who bet on high quality. They invest heavily in powerful production facilities, register their own brand and work on its reputation.

Specifications of the Husqvarna 240 chainsaw

Husqvarna 240 saw is based on a 2-stroke engine with a carburetor. Runs on gasoline and oil mixture. Engine life is increased by improvements to the crank and crank assembly and special cylinder coating. 20% better fuel economy thanks to innovative X-Torq system that also lowers harmful exhaust emissions. Generously sized fuel tank and low fuel consumption to extend tool life, without refueling.

Otherwise the saw has these technical features:

  • 2 litre capacity. с.;
  • chain pitch. 3/8 inch;
  • Fuel tank capacity is 300 ml;
  • Oil tank. 200 ml;
  • bar length. 40 cm
  • weight. 4,7 kg.

How to adjust the carburetor on a Husqvarna 240 chain saw?

Every machine is subject to occasional malfunctions. The main malfunctions of the Husqvarna 240 chainsaw are related to repair of the carburetor, other components of the fuel system, with malfunctions of the oil pump. If the oil pump is broken the chain on the Husqvarna 240 chain saw does not turn because there is no oil. Also, a damaged gas tank or fuel hoses may be the reason why the saw leaks gas. If the saw has absolutely stopped to start, first of all you should check the quality of the fuel mixture, check the spark plug ignition. If necessary clean or replace the spark plug with a new one, adjust the carburetor.

The carburetor also needs adjustment if your chain saw won’t start or cuts out under load, or if the fuel type or operating conditions have changed. Carburetor adjustment is worthwhile after preliminary cleaning of air filters and warming up of the engine.

Then follow this algorithm:

  • Screw L turned all the way to the maximum. Then immediately turn the screw back a quarter turn.
  • While holding the throttle grip, turn the H screw a quarter turn.
  • Stop the throttle and turn the T-handle screw clockwise until the chain starts to move. Then immediately turn the screw back until the chain stops.
Read more:  What Gasoline In The Stihl Chainsaw

See the diagram below for the location of the respective screws:

How to adjust the carburetor on a Husqvarna 240 chain saw?

Any technique is subject to breakdowns from time to time. The main malfunctions of the chainsaw Husqvarna 240 are related to the repair of the carburetor, other components of the fuel system, malfunctions of the oil pump. If the oil pump breaks, the chain for the Husqvarna 240 chain saw stops turning because it is not lubricated. Damage to the gas tank or fuel hoses may also be the cause of the gasoline leaking from the saw. If the saw has absolutely stopped starting, first of all you should check the quality of the fuel mixture, check the spark plug spark. If necessary, the plug is cleaned or replaced with a new one and the carburetor is adjusted.

You also need to adjust the carburetor if your chain saw won’t start right away, throttles on exertion, or if the fuel type or operating conditions change. Carburetor adjustment should be performed after preliminary cleaning of air filters and warming up of the engine.

Then follow the following algorithm:

  • Screw L is rotated to maximum. Then turn the screw back a quarter turn right away.
  • Hold the throttle trigger and turn the H screw a quarter turn.
  • Release the throttle and turn the T-screw clockwise until the chain starts to move. Then immediately turn the screw back until the chain stops.

The layout of the corresponding screws is shown below:

Modern chain saws have a complex system and consist of several major components that require periodic maintenance and adjustment. In this article we will talk about how to adjust the carburetor on a Husqvarna chainsaw.

When the carburetor on your Husqvarna chain saw needs adjustment

Problems, the solution of which can be the adjustment of the carburetor, quite a lot. Adjusting the carburetor of a Husqvarna chainsaw is necessary if there are such malfunctions as:

  • Excessive idle speed;
  • strong smokiness when working with the tool;
  • Difficulty starting a cold or hot engine;
  • Lack of traction and low maximum rpm.

This is by no means a complete list of problems, the solution to which can be the adjustment of the carburetor Husqvarna. In a number of cases, adjustment of the quality and quantity of the fuel mixture is carried out after the engine overhaul or in the course of a scheduled maintenance of the chainsaw.

The Husqvarna AB manufacturer recommends adjusting the carburetor before and after the running-in period.

Consumer Reviews

You can adjust the chain saw “Husqvarna 142” on your own. This feature is considered by consumers as a plus, as well as the fact that the crankshaft in the construction is made of forged steel. The advantage is also quite easy access to the air filter. The ignition system is durable and simple. The piston group has two compressor rings, which have a longer service life. The manufacturer emphasizes that they will be ready to last up to 5 years.

Customers also like the fact that the cylinder liners have a chrome-plated, wear-resistant coating. You might not have to adjust the Husqvarna carburetor, because the manufacturer claims it’s the best in its class. The design is also good because it has a built-in primer. It is a pump that gives the engine a quick start. This feature is independent of ambient temperature.

Adjusting the carburetor on a Husqvarna saw.

For the running-in mode, so that the parts receive enough lubrication, setting the carburetor of chain saw Husqvarna made in such a way that the maximum rpm was at 600-700 rpm. lower than the work surface. If it is not possible to set the maximum working frequency with the tachometer, it is not necessary to change the presetting with the H screw. The manufacturer does not authorize an excessive increase in the maximum rpm setting. If, after completing the adjustment, the saw chain is still moving when the engine is idling, turn the screw T counterclockwise to make it stop completely.

To adjust it accurately, the saw should be warmed up for at least 10 minutes and set on a flat surface. The tire should be pointing in the opposite direction from the person doing the tuning. At the first stage the highest value of the idling speed should be found. To do this turn the screw L slowly from left to right before turning it clockwise. When the maximum rpm has been determined by experiment, turn the L screw counterclockwise to the value of 1/8 to a quarter of a full turn.

Read more:  How to determine which chain is on a chainsaw

To set the idle speed use the nozzle marked T. It should be turned from left to right until the chain starts to move. Then turn it gently in the opposite direction until the chain stops turning. The H screw is considered to be set correctly if the noise of the saw remains small at full throttle without load. If the exhaust is too smoky and the saw makes a loud noise, the mixture is too rich. You need to turn the H jug clockwise until it sounds right. You can see how to set the carburetor correctly in the video below.

Adjusting the carburetor of the Husqvarna saw.

For the running-in mode, so that the parts get enough lubrication, the carburetor setting of Husqvarna chain saw is made in such a way that the maximum rpm was 600-700 rpm. below the operating range. If it is not possible to set the maximum working speed on the tachometer, you should not change the presetting with the H screw. Do not exceed the maximum rpm allowed by the manufacturer. If after completing the adjustment if the chain moves when the engine is idling, turn the screw T counterclockwise to make it stop completely.

For proper adjustment the saw should be warmed up for at least 10 minutes and placed on a flat surface. The direction of the guide rail must point in the opposite direction to that of the person making the adjustment. At the first stage the highest idling speed should be found. To do this turn the screw L slowly from left to right and then back to the right. When the maximum rotational speed has been determined by experiment, turn the screw L counterclockwise to the value of 1/8 to a quarter of a full turn.

adjust, idle, speed, husqvarna, chain

The idle speed is adjusted using the nozzle marked T. It should be turned from left to right until the chain starts to move. Then turn in the opposite direction smoothly until the chain stops turning. Screw H is set correctly if the noise is not too loud at full throttle and no load. If the exhaust is too smoky and the saw makes a loud noise, the mixture is too rich. Turn the H jug clockwise until the sound is correct. To see how to properly set the carburetor, watch the video below.

Model Specifications

Husqvarna brand 142 chain saw has solid factory parameters.

  • petrol engine power. 2,58 l. с./1,9 kW;
  • Idle/maximum rpm. 3000/13000 rpm;
  • The manufacturer’s recommended length of the tire to be used is 30-38 cm;
  • weight with fuel and oil tanks: 4,9 kg.
adjust, idle, speed, husqvarna, chain

Despite the impressive maximum rpm parameters the engine of the Husqvarna model runs quietly enough. When operating the model under maximum load, the operator will be exposed to an audible level of 105 dB.

Tools required for the work

Before you start tuning your Husqvarna carburetor, take care to have all the tools you may need. To carry out this type of work yourself, you will need:

An ordinary slotted screwdriver will not work for adjustment. к. adjustment screws on Husqvarna chain saws can have different cross sections. You will have to buy a special, this is a feature of Husqvarna chainsaw repair, they have made everything so that the saw can be repaired only in a specialized service Husqvarna.

Algorithm and description of adjusting a Husqvarna carburetor

Husqvarna carburetor, is regulated similar to how the carburetors on chainsaws of other manufacturers are adjusted.

Before carrying out the adjustment you need to check that there is no blockage in the fuel supply and that there is no air sucking into the carburettor. Also check that the air filter is clean and replace it with a new one if necessary.

  • On a turned off saw the Husqvarna carburetor is reset to factory settings.
  • Start the engine and warm it up for a few minutes.
  • By turning the screw (L) clockwise, the position is found at which the engine develops the maximum RPM, after which the screw should be turned back 1⁄4. If in this case the chain of the chainsaw rotates, it is necessary to reduce the idle speed by adjusting the position of the screw (T).
  • The next step is to adjust the power of the Husqvarna at maximum rpm and adjust the number of rpm. For this purpose connect the tachometer to the started chain saw, press the throttle grip all the way down and then check the tachometer reading. If the maximum rpm differs from the maximum recommended by the manufacturer, change the position of the screw (H) to bring the tachometer reading back to normal.
Read more:  How to lubricate the upper gearbox on a chain saw

Husqvarna chainsaw carburetor

Partner, STIHL and Ural carburetors

Setting the carburetors of these tools can only be done by yourself if you have some knowledge and a tachometer. Otherwise, adjustment of the tool should be carried out by a professional mechanic.

The carburettor is set for optimum performance by the manufacturer. The user has the possibility to make corrective adjustments, the need for which arises quite seldom.

If during the adjustment of chain saws brands Partner, STIHL and Ural is used fuel with a different quality composition from the standard, the adjustment is done with the screws L and H. To reduce the octane rating and increase the RPM, turn the screws from left to right. To increase the octane rating, you should set a low rpm and turn the screws from right to left.

A quality carburetor tune-up of the Partner, STIHL and Ural chainsaws involves the following conditions

  • Make fine adjustments only when the engine is hot and with a minimum run time of ten minutes;
  • Always check that you have a clean air filter;
  • The rotating chain is stopped by turning the adjusting screw from left to right until it stops completely.

When you are making the adjustments, observe safety precautions and hold the chain away from you. It is recommended to use the services of professionals to adjust the Ural brand tools.

Adjusting the chainsaw carburetor with your hands

Adjusting the chain saw’s carburetor ensures that it runs efficiently at full throttle while consuming less fuel. Adjustment should be performed with a clean fuel filter and air filter. For more carburettors, adjustment is performed with three screws: full speed, minimum speed and idle speed adjustment.

Use screws H and L to adjust the gasoline/air mixture ratio determined by the carburetor throttle opening. Unscrewing the screws enriches the mixture and lowers RPM accordingly.

The designation H refers to the maximum rpm screw controlling the main nozzle, L. refers to the minimum revolutions screw controlling the idle speed nozzle. Precise idling speed adjustment is achieved with the adjusting screw S. Sometimes, to simplify the adjustment, the number of available adjustment screws of the carburetor is reduced.

Setting the carburetor chain saw is divided into two steps. the basic (factory settings), carried out when the engine is off. and final, performed with the engine running warm. The exact values of the rotation angles should be taken from the instruction manuals for the particular chainsaw. Failure to follow the manufacturer’s instructions can result in damage to the engine.

The maximum H and minimum L rpm setting screws should be turned slowly clockwise as far as they will go and then turned back two turns

To find the greatest idle speed, to do this slowly turn the screw L in different directions. After finding the position of the maximum engine rpm it is necessary to turn the screw L by 1/4 of a turn counter-clockwise. If the chain still rotates at idle, turn the screw T or (S) counterclockwise until it stops.

Check and Adjust Maximum RPM.

Changing the maximum rpm is done by the H screw. If it is turned in (clockwise rotation) revolutions are increased, if it is turned counterclockwise. revolutions are increased up to 11500-15000 rpm. decreases. Chainsaw engines have a maximum rpm of 11500 rpm. up to 15000 rpm. A higher speed is not provided by the ignition and becomes dangerous for the engine. Limit revolutions can be determined by the ignition interruption. If it occurs, turn counterclockwise the H screw a little.

If the engine is not tested for acceleration and maximum rpm then the chainsaw adjustment cannot be considered complete.

When the throttle trigger is pulled smoothly, the engine should quickly and steadily climb from idle to maximum rpm (2,800 rpm or higher).to 11500-15000 rpm depending on the machine). If the revolutions are slow and lag behind, turn the L screw slowly anticlockwise, but not more than 1/8 of a turn.

After adjusting the acceleration and maximum rpm, you should check the saw’s idle speed again. The motor should run steadily, the chain should not move. Chainsaw adjustment must be repeated if this condition is not met but except for the basic adjustment step.