The reasons why you will need to adjust this assembly can be listed for a very long time.
Among the main faults are the following:
- Increase the revolutions at idle speed;
- The appearance of a large amount of smoke during operation;
- Deterioration of starting properties;
- Insufficient power of the tool when cutting.
This is not a complete list of all known problems. Sometimes it is necessary to adjust the carburetor on a Husqvarna chainsaw after the power tool has been overhauled or after service work has been performed.
The developers of the Husqvarna 137 write in the datasheet that carburetor adjustment should always be performed before and after the run-in of the tool.
When the carburetor needs adjustment?
There are many reasons to check the carburetor, and it can take a very long time to list them all.
Among the main malfunctions are the following:
- RPM increase at idle speed;
- The appearance of a large amount of smoke during operation;
- Deterioration of starting characteristics;
- Insufficient power of the tool when cutting.
Here is not a complete list of all known faults. Sometimes such a procedure as adjustment of the carburetor on a Husqvarna chainsaw, it is necessary to carry out after a major repair of the power unit or after maintenance.
The developers of the Husqvarna 137 write in the datasheet that carburetor adjustments should always be performed before and after running-in of the tool.
Why do I need to adjust my Husqvarna carburetor?
The carburetor is one of the important mechanical assemblies that make up a chainsaw. Its tasks include mixing fuel with air and supplying the resulting composition to the engine. But in the process of work of a chainsaw there are situations when adjustment of a carburetor of Husqvarna becomes necessary. Depending on the reason, adjustment of the carburetor of the 142 Series and other chainsaw models is performed to prevent the following situations:
Since the carburetor affects the quality of fuel, in the first case, the need to adjust the carburetor saw 137 or other professional series, such as Husqvarna 240 or 260 involves influencing exactly the amount of fuel entering the carburetor to mix with the air mass. It is known that the maximum performance is possible only in a certain ratio. The second point of carburetor mixer adjustment of a chainsaw is caused by a lack of incoming air, which provokes underburning of injected gasoline with its output in the form of thick smoke. Timely change of parameters with your own hands to reduce the amount of injected fuel will reduce the consumption of this product much faster.
Repair by your own forces will save not only the budget, but also the time spent on transportation and the queue at the repair shop. The same applies to the replacement of various spare parts in gasoline-driven tools, such as a chain on a chainsaw or a universal trimmer head on a brushcutter, or oil for electric drive products.
Adjusting the carburetor on a Husqvarna chainsaw
Like all other saws, the Husqvarna has the same algorithm for adjusting the carburetor. Therefore, the instruction will also be relevant for other tools and chainsaw models such as the Husqvarna 142. 236.
Before starting work, make sure that the air filter is clean and that all other assemblies are working properly. The fuel supply to the float chamber should run smoothly and the ignition system is set correctly and has a fresh spark plug.
- Set the factory settings of the carburetor. Do this with the engine stopped.
- Now you can start the engine and be sure to warm it up for a few minutes. Adjusting the idle speed of the carburetor Husqvarna 137 is made only on the warmed up motor.
- Turn the L screw clockwise to set the highest rpm of the crankshaft, then turn it back a quarter of a turn. Use screw T to adjust the crankshaft RPM so that the chain does not rotate. It must not be actuated without pressing the gas pedal.
- Now you need to set the maximum rpm and their power. It is sufficient to connect the tachometer to the ignition and set the rpm to the highest possible with the gas pedal. Compare it with the data sheet. If they differ, then unscrew or tighten the screw H. By varying the range it is possible to create limits to make the saw efficient and to save the life of the motor.
Things to watch out for?
Once the adjustment of the Husqvarna carburetor is completed, you should make sure that the engine is stable and that the saw easily picks up and releases the necessary revolutions. It is considered abnormal for the chain to rotate at idle speed and it is again necessary to adjust its coupling with the clutch by means of the screw H.
Remember that it takes some time to adjust the assembly, because the Husqvarna chain saw does not respond immediately to the screws. This time can vary from 5 to 15 seconds. These times are not prescribed in the schedule, so can only be determined experimentally.
If after adjustment there is a huge amount of smoke during operation, it is necessary to adjust the fuel and oil mixture supply. For this turn the L screw.
What is the factory setting on a Husqvarna chainsaw carburetor??
In order for the chain saw to still start even if it is not properly adjusted, the factory H and L screw positions are used. Most Husqvarna chain saws can be started by unscrewing both screws exactly one and a half turns. Only then can you change the screw positions to achieve the correct fuel consumption and maximum efficiency. You can also adjust the throttle after these adjustments.
If you still have questions about carburetor adjustment on Husqvarna 137 chain saw and other models of this series I recommend to see this
How to adjust the carburetor on the Husqvarna 142 chain saw
owning a chainsaw makes life a lot easier, even for hobbyists, and in some businesses this tool is virtually indispensable. However, like any relatively complex device, the chainsaw requires periodic maintenance. All kinds of malfunctions can occur because of untimely or poor maintenance or as a result of routine or excessive use. For professionals, an intermittent or unstable saw cuts down on performance or can cause a ruined day’s work. One of the fairly common malfunctions is improper adjustment of the chainsaw carburetor, which is thrown off due to failed attempts to adjust or shifting the adjustment screws for other reasons.
HOW TO SET THE carburetor on your chainsaw. How a chainsaw carburetor works
You don’t need to be a professional motor technician to adjust a chainsaw carburetor yourself. However, you still need to learn some aspects of carburetor operation that relate to the process of preparing the fuel mixture.
The vast majority of chainsaws are equipped with Chinese-made Walbro carburetors. Their design is simple, if not primitive. There is a monoblock body of straight-through type with a through hole. Inside the hole there is a diffuser. a narrowing of the passage with a fuel injection channel. On both sides there are throttle valves: the smaller one is a throttle valve, it regulates the amount of fuel mixture to be injected in the cylinder. The larger flap, the air flap, is used to limit air flow during a cold start.
Arrangement of Walbro carburetor: 1. fuel inlet fitting; 2. diaphragm pump pulse channel; 3. inlet valve; 4. fuel pump diaphragm; 5. outlet valve; 6. filtering mesh; 7. air flap; 8. throttle flap; 9. fuel channel; 10. idle stroke adjusting screw; 11. needle; 12. idle stroke nozzles; 13. control membrane; 14. fuel chamber; 15. main nozzle; 16. diffuser; 17. main adjusting screw
All the magic of fuel preparation takes place in the hidden channels and the diaphragm pump chamber. When you turn the throttle valve, the channel through which the fuel is injected into the mixing chamber increases slightly and the fuel comes in at a larger volume. The carburetor has two sort of valves: one for low and one for high. When you change the throttle position the fuel flow changes proportionally between these two valves.
The need for such a device is that idling and under load the quality of the mixture should be different. In this case, the channel through which the fuel is fed to the mixer at idle RPM is not completely blocked when the engine accelerates, and vice versa. the channel of maximum RPM is a bit prying at idle RPM.
Design and operating principle of the Husqvarna carburetor
To successfully set the carburetor on your Husqvarna chain saw you need to know how it works and understand how it works. In fact, everything is not as complicated as it seems at first sight.
The carburetor has an internal fuel pump that is responsible for transporting the gasoline-oil mixture, a diaphragm, and a needle valve with a butterfly valve. They work together to dose the fuel flow in the main chamber and the two flaps.
One of the throttle valves is designed to regulate the fuel flow into the cylinder when the throttle is depressed, it is called throttle valve, the second is responsible for limiting the air supply from the air filter to facilitate starting a cold Husqvarna chainsaw. The moment the operator cuts off the air flow to the carburetor with the choke, the fuel mixture is thinned and the flow to the cylinder is increased, making the chain saw much easier to start than when starting in standard cold start mode.
Husqvarna carburetors have a jets valve, which atomizes the fuel and prevents the air from getting into the main chamber. Often problems with the operation of the saw can be caused by defects in this very element. For example, the valve, if improperly stored chainsaw can stick, the fuel supply will stop, making it impossible to operate the engine. also malfunctions of injectors can cause air leakage in the carburetor’s main fuel chamber. In such cases, adjusting the position of the adjusting screws will not correct the situation, you need to repair or replace the unit.
For the adjustment of the quality and quantity of mixture, as well as the number of revolutions of the crankshaft in the idle mode are responsible for three adjustment screws installed in the carburetor housing:
- Screw (L). regulates the amount of fuel in low and medium revolutions;
- (H). responsible for traction at high revolutions and their quantity;
- (T). it changes the throttle flap position, thereby regulating the amount of fuel mixture flowing into the cylinder and the engine operation of the tool in idle mode.
Screws (L) and (H) cannot be adjusted without some knowledge and experience. Improper adjustment of the quality and quantity of the fuel mixture can cause the engine to stop working or to run incorrectly, leading to rapid wear or even jamming.
Design and application
Husqvarna two hundred 40 chain saw is not limited to the standard functions of making firewood. With its help you can easily clear a huge area from shrubs and old trees, shape the crowns of ornamental plants in the garden, use it in the construction for sawing boards. Sufficient power and bar length to cut wood both lengthwise and crosswise.
Traditional brand design is mixed in this model with the highest technical features and usability. The Husqvarna two hundred and forty saw is in the domestic class, but its performance is not much different from professional tools. Manufacturers have provided such necessary functions in this saw as easy start, double air cleaning, vibration reduction. Ergonomic control levers and handlebar settings increase operator comfort and reduce strain. Main components are positioned to be easily accessible in case of repair.
If you follow the instruction manual and often carry out preventive inspections of the chainsaw, repairs can almost always be avoided. But even in case of breakage the tool will not cause you significant inconvenience. unique spare parts are simply available for purchase and replacement. Detailed structure Husqvarna chain saws
Husqvarna chain saw carb adjustment
Husqvarna 240 chainsaw, whose technical properties you can see below. It’s the equipment that follows the Husqvarna 236 mowing line. If you compare the two variations, it should be emphasized that the latter has a higher power, slightly longer bar and has a motor that saves fuel up to 25%.
The chainsaw “Huskvarna 240”, the repair of which is required not so often, is an environmentally friendly inventory, which is very important for some consumers. The amount of harmful emissions into the atmosphere is reduced, and the number of cuts on a single fuel for refueling is increased. Quite often the products of the aforementioned Swedish company are compared to the manufacturer of chainsaws STIHL. As an advantage of the first, it should be emphasized that a primer is available to simplify starting. But as practice indicates, it does not have a significant impact on the process of starting the equipment.
Reviews of the model
But this list of consumers is not considered complete. They like the presence of the brake lever in the model, it entices both the ergonomic design, small exhaust volume, and the presence of the chain tensioner.
This model costs thirteen thousand. and has an air cleaning system that reduces filter wear. the engine in the device is quite reliable and powerful, it contributes to economical consumption of fuel, reducing the amount of harmful emissions. The chainsaw needs to warm up during start-up. As the cool tool is started, you should let it run for 30 seconds. Then you can use and release the throttle lever. This will prepare the tool for work.
Described in this section chain saw “Husqvarna 240”, the technical properties of which are fascinating to you, has a bar 40 cm, also the capacity of two liters. of. The power of the motor is 38.2 cm 3, and the fuel tank. 0.3 liters. Pour oil into the tank can 0.2 liters. Before you buy this equipment, you should consider that it belongs to the household class and weighs 4.7 kg. The number of connections in the equipment is 56, the width of the slot. 1.3 mm, but the noise level is 100.7 dB.
How to remove the carburetor and whether it is necessary to do before adjusting
If the chainsaw has low RPM or, on the contrary, operates at an excessively high RPM, the carburetor can be adjusted without removing the carburettor.
But if the chainsaw won’t start, the rpm’s freeze up or it runs unstable. Adjusting the chainsaw carburetor won’t change the situation. It should be removed for cleaning or replacement of parts. Use the following procedure for this:
- After unscrewing the fasteners, remove the saw’s top cowl.
- Remove the gasket and part of the air filter by unscrewing the bolts or snapping off the retainers.
- On the right side of the carburetor is the fuel hose. Remove it together with the air damper control rod.
- Remove the carburettor from the fasteners that hold it.
Disassemble the carburetor according to the supplied instructions. When disassembling carefully stack the parts on the prepared cloth. Because of its small size there is a risk of losing parts when disassembling 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 with compressed air, if possible, prewash them in an ultrasonic bath.