How To Remove The Carburetor From A Husqvarna 240 Chainsaw

How to properly adjust the carburetor of a Husqvarna chainsaw with your own hands Instructions for adjusting the carburetor of a Husqvarna chainsaw. The device and principle of operation of the unit of the internal combustion engine power system. When is it necessary to make a setting and what tool is needed for this. How to remove the necessary parts, adjust and assemble your Husqvarna saw with your own hands. Photos and

How to remove the carburetor and whether to do it before tuning

In the event that the chainsaw does not develop speed or, on the contrary, works at too high, the carburetor can be adjusted without removing it.

But if the chainsaw does not start, the rpm freezes at the same level or it is unstable. Chainsaw carburetor tuning will not change the situation. It must be removed to clean or replace parts. In this case, it is necessary to act in the following order:

  1. After unscrewing the retaining fasteners, remove the upper saw cover.
  2. Remove the gasket and part of the air filter by unscrewing the bolts or unscrewing the fasteners.
  3. There is a fuel hose on the right side of the carburetor. We remove it together with the air damper control rod.
  4. Remove the carburetor from the mountings that hold it.
how to remove the carburetor from a Husqvarna 240 chainsaw

Disassembly of the carburetor is carried out in accordance with the instructions supplied with the kit. When disassembling, be very careful when folding the parts onto the prepared fabric. Due to its small size, there is a risk of losing components during disassembly and flushing.

All parts obtained in this way are washed in a special liquid, dried and wiped with a lint-free cloth.

Channels, tubes and nozzles are blown out with compressed air, if possible, having previously washed them in an ultrasonic bath.

The device and principle of operation of the carburetor

The carburetor is used to prepare a combustible mixture in an operator-defined proportion of 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 a Husqvarna chainsaw.

Its design consists of the following elements:

  • Body with clamping bolts and a set of gaskets;
  • A fuel pump is a device that pumps a gasoline-oil mixture into the carburetor;
  • The diaphragm is designed to limit the supply of a combustible mixture to the engine;
  • The float chamber collects fuel 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 passes air 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 is a section of narrowing of the air supply tube at the point of fuel injection;
  • A needle valve a device that regulates the fuel supply;
  • Jet screws that regulate the flow of the mixture at high and low speeds, as well as the 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 to make starting a cold engine easier.

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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 effect on engine performance. Long-term storage may cause the nozzle to 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 is mixed 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.

Ignition adjustment after carburetor adjustment

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

  1. The 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, readjust the carburetor. 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.

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.

Husqvarna 142: how to adjust the carburetor of this chainsaw with your own hands

And this brand and model have no peculiarities or differences. All adjustments of the carburetor of the Husqvarna 142 chainsaw (as well as the 137 or 240 models) are made by hand according to an algorithm similar to step-by-step instructions. This is the most common configuration option, which is why it was given in the above instructions. For example, the carburetor of the Carver chainsaw is also adjusted in the same way.

How to set up a chainsaw carburetor if it won’t start at all

Quite a common problem in cases when a master from the series tries to get into the settings, I know everything with hands that do not grow from the shoulders. In such a case, there are standard screw positions from which you can dance further. First, you need to completely tighten both screws (do not overdo it). Then unscrew:

  • Screw L one revolution;
  • Screw H one and a half turn.
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With regard to the idle screw, the throttle must first be completely closed (screw T removed). After that, it must be cranked one and a half turns clockwise and try to start the engine. If it did not work out, it is gradually added by a quarter of a turn before starting. When the engine starts to work, the position of the idle screw is adjusted so that the internal combustion engine does not stall, but the chain is still in place.

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How to correctly and accurately adjust the carburetor: step by step instructions

To make the information easier to perceive, we propose to consider it on the basis of photo examples with a description of actions in tabular form. The basis is a chainsaw with initial settings.

You can learn more about the master class on adjusting the carburetor of a chainsaw in this.

Factory settings

The factory default setting for the Husqvarna carburetor is the position of the screws (H) and (L), in which a working chain saw is guaranteed to start. For Husqvarna tools, this is one and a half turns from fully tightened screws (H) and (L). In the process of adjustment, 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 in the course of carrying out a complete diagnosis of the Husqvarna chainsaw, carburetor defects were found, then some of them can be repaired without contacting a Husqvarna AB service center. For example, you can independently:

  • Change the gaskets under the covers of the main chamber and the fuel pump;
  • Clean or replace the mesh filter;
  • Replace the diaphragm or needle valve of the main chamber;
  • Troubleshoot the fuel pump diaphragm.

Gaskets, diaphragms and a rocker needle valve can be found in the repair kit that is available for each Husqvarna chainsaw carburetor model.

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 is faulty, manufacturers recommend changing the carburetor completely.

The first thing to do before removing the carburetor from Husqvarna is to clean the saw with a compressor, since dirt can interfere with a quality repair. Next, you need to open the top cover of the chainsaw, remove the air filter, disconnect the rods from the control levers of the air and throttle valves. Then unscrew the screws securing the carburetor.

It is quite easy to disassemble the carburetor body for repair. The main chamber cover is held in place by four screws that can be removed with a regular screw, the fuel pump cover is secured with one wide screw.

Below is a look at which it will become clear exactly how you can repair the carburetor without contacting a Husqvarna service center.

The structure and principle of operation of the Husqvarna carburetor

To successfully tune your Husqvarna chainsaw carburetor, you need to know its design 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 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 choke, the fuel mixture becomes leaner and its supply to the cylinder increases, due to which the chainsaw starts much easier than in the case when a cold start is carried out in normal mode.

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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 saw operation 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; repair or replacement of the unit will be required.

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 low and medium speed modes;
  • (H) is responsible for traction at high rpm and their number;
  • (T) changes the position of the throttle valve, thereby adjusting the amount of fuel mixture entering the cylinder and the engine idling of the tool.

DIY repair of Husqvarna and Stihl chainsaws:

Chainsaws, simple in design and reliable in operation, are very popular among owners of private houses and summer residents. When handled correctly, this tool will last a long time and rarely break. over, it will not be difficult to eliminate the cause of the chainsaw malfunction with your own hands, especially if you know where to look for the cause.

DIY Stihl chainsaw repair

This brand is very popular among both individuals and professionals. This easy-to-use and reliable tool can last a long time without repair. There are situations when the Stihl chainsaw does not start or stalls right after the factory. You can find out what to do in these cases by looking at the instructions.

Husqvarna chainsaws major faults

The Swedish manufacturer’s tool can turn hard work into a simple task. Chainsaw models Husqvarna 137, Husqvarna 240 and Husqvarna 365 features three features:

  • High engine power;
  • Improved engine filtration system;
  • The ability to absorb unnecessary vibrations.

If the tool is operated strictly according to the instructions and its malfunctions are eliminated in a timely manner, then it will delight with reliable and stable operation. Correctly carried out repairs with original spare parts will allow you to use the saw for a long time.

The main cause of chainsaw breakdown is most often engine failures, which can manifest as follows:

  • Do not start;
  • Unstable work at idle;
  • Start up and immediately stall;
  • Do not have enough power.

In this case, the malfunction should be sought in the ignition system, piston group or fuel system. Often, the reason for poor performance of the tool can be associated with the clutch, brake system, lubrication mechanisms, tire.