Modern chainsaws have a complex system and consist of several basic components that periodically require maintenance and adjustment. This article will talk about how to adjust the carburetor on the Husqvarna chainsaw.
In what cases the carburetor chainsaw Husqvarna requires adjustment?
Problems, which may be the adjustment of the carburetor, quite a lot.
Adjusting the carburetor of the Husqvarna chainsaw is necessary when faults such as:
- increased idling speed;
- strong smoke when working tool;
- difficulty starting a cold or hot engine;
- lack of thrust and reduced maximum speed.
It is not a complete list of problems that can be solved by setting the Husqvarna carburetor. In some cases, the setting of the quality and quantity of the fuel mixture is carried out after an engine overhaul or in the course of scheduled maintenance of the chainsaw.
Manufacturer Husqvarna AB recommends that the carburetor be adjusted before and after running in.
Device and principle of operation of the “Huskvarna” carburetor.
For successful tuning of the carburetor chainsaw Huskvarna need to know his device and understand how it works. Everything is not as difficult as it seems at first glance.
The saw carburetor has a built-in fuel pump that is responsible for transporting a mixture of gasoline and oil, as well as a diaphragm, a needle valve with a rocker. Their joint work allows metering fuel supply to the main chamber and two dampers.
One of the dampers is designed to regulate the supply of fuel to the cylinder when the gas is pressed. It is called a throttle valve, and the second is responsible for restricting the air supply from the air filter to facilitate the launch of a cold Husqvarna chainsaw. At that moment, when the operator blocks the air supply to the carburetor using the air flap, the fuel mixture is depleted, and its amount to the cylinder is increased, due to which the chainsaw starts much more comfortable than in the case when the cold start is performed usually.
In the operation of the carburetor, Huskvarny participates valve-nozzle, which sprays the fuel and prevents air from entering the main chamber. Often problems with the saw can be caused by defects of this particular element. For example, the valve, if the chainsaw is not stored properly, can stick, the fuel supply will stop, which will make the engine impossible to work. Also, violations of the injector can cause air leaks into the main fuel chamber of the carburetor. In such cases, the adjustment of the position of the adjusting screws will not correct the situation; repair or replacement of the node will be necessary.
For setting the quality and quantity of the mixture, as well as the number of revolutions of the crankshaft in idle mode, there are three adjustment screws installed in the carburetor body:
- screw (L). adjusts the amount of fuel in the mode of low and medium speed;
- (H). is responsible for the thrust at high speeds and their number;
- (T). changes the position of the throttle valve, thereby regulates the amount of fuel mixture entering the cylinder and the engine operation of the tool in idle mode.
The screws (L) and (H) cannot be adjusted without having certain knowledge and experience. Incorrect setting of the quality and quantity of the fuel mixture can lead to the fact that the engine will stop working or will work incorrectly, leading to its rapid deterioration or even jamming.
Tools required for work.
A conventional slotted screwdriver is not suitable for adjustment since the adjustment screws on Husqvarna chainsaws can have a different section. We will have to purchase a special one, in this feature of repairing Husqvarna chainsaws, they did everything so that the saw could be repaired only in the specialized Husqvarna service.
Algorithm and description of setting “Husqvarna” carburetor.
Carburetor Husqvarna is regulated in the same way as setting up carburetors on chainsaws from other manufacturers.
Immediately before adjustment, it is necessary to carry out a full diagnostics of the saw and make sure that there is no difficulty in the supply of fuel and air leaks into the crankcase chainsaw. You must also ensure that the air filter is clean and, if necessary, replace it with a new one.
The order of work is as follows:
- The factory setting of the Husqvarna carburetor is set on a dead saw.
- The engine is started, and the saw is warming up within a few minutes.
- By turning the screw (L) clockwise, there is a position at which the engine develops maximum revolutions, after which the screw must be turned back 14. If at this the chain of chainsaw rotates, then it is necessary to reduce the idling speed, by adjusting the position of the screw (T).
- The next stage is to adjust the power of Huskvarna at maximum speed and adjust their number. To do this, the tachometer is connected to a chain saw, the throttle knob is fully squeezed out, and then the tachometer is checked. If the value of the maximum speed differs from the maximum amount recommended by the manufacturer, then by changing the position of the screw (H) the tachometer readings are returned to normal.
After the adjustment, the chainsaw should easily pick up and slow down, work steadily at low and high rpm. If the saw chain rotates at idle after making adjustments to the carburetor control screws, this is a sign that the adjustment was made incorrectly and you need to correct the position of the screw (T).
Also, when adjusting the Husqvarna carburetor, you should consider the response time of the chainsaw to the rotation of the screws. Settings do not change immediately, but within five, ten seconds.
One of the indicators of improper adjustment is strong smoke when the saw is working, which indicates a large amount of fuel entering the combustion chamber. If such a situation arises, you need to adjust the position of the screw (L).
The factory default settings for the Huskvarna carburetor are the position of the screws (H) and (L) in which the working chainsaw must be guaranteed to start. For Husqvarna tools, this is one and a half turn from fully twisted screws (H) and (L). In the process of adjustment, you must first install the screws in the standard position, then start the chainsaw and make an accurate adjustment of the power, the number of maximum revolutions and idling.
DIY carburetor repair.
If during the complete diagnosis of the Husqvarna chainsaw, carburetor defects were detected, some of them can be fixed without contacting the 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 strainer;
- replace the diaphragm or needle valve of the main chamber;
- troubleshoot the diaphragm of the fuel pump.
Gaskets, diaphragms and a needle valve with a rocker can be found in the repair kit, which is available for each model of carburetors Husqvarna chainsaws.
Also, if you have a specific experience, you can try to restore the faulty injector valve, but you cannot guarantee a positive result when trying to restore the injector, if it fails, manufacturers recommend changing the carburetor completely.
The first thing you need to do before removing the carburetor from Huskvarna is to clean the saw with a compressor since the dirt can interfere with the quality of the repair. Next, you need to open the top cover of the chainsaw, remove the air filter, disconnect the thrust from the air, and throttle control levers. After that, unscrew the carburetor fastening screws.
Disassemble the body of the carburetor for repairs quite simple. The lid of the main chamber is held by four screws, which can be removed using a conventional screwdriver; the fuel pump cover is fixed with one full screw.
Below is a video, looking at which it will become clear exactly how the carburetor can be repaired without contacting the Husqvarna service center.
Work on setting up or repairing the carburetor on Husqvarna’s chainsaws can be done without any specific experience. To do everything right, you must follow the algorithm and have a minimum set of tools. It is also worthwhile to assess your strength in advance and not risk it if you do not understand anything in technology. Sometimes it is better to pay a small amount to the master than to spoil the instrument by self-adjustment.