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 fine adjustments to the power, the number of maximum revolutions and idling.
Purpose, design and principle of operation of the carburetor.
The carburetor is needed to prepare the air-fuel mixture to power the engine. If the proportions in this mixture are not correct, the motor will malfunction. If the proportion is not observed in the direction of an increase in the amount of fuel, the mixture is called oversaturated, if, on the contrary, there is little fuel. Poor one. Both of them do NOT have the best effect on engine operation.
In different models of chainsaws, Carburetors differ in design, but they are similar in principle of operation. The air stream moves at high speed through the air channel. A damper blocking the channel allows you to change the speed of the air stream. The fuel is fed through the nozzle into the channel, where it mixes with the incoming air, forming a fuel-air mixture. The resulting mixture enters the engine.
The pressure in the float chamber, where the fuel is located before mixing, is practically equal to atmospheric pressure. But a vacuum is created in the air channel, due to which the fuel is drawn into the air stream. The more the damper is opened, the faster the air moves, and the amount of fuel also increases. The engine speed increases. So you can simplify the principle of the carburetor.
Chainsaw carburetor adjustment is required for efficient, smooth operation of the tool, getting maximum output and at the same time economical fuel consumption. Check the fuel and air filters before adjusting. They must be clean. On most chainsaws, adjustment is carried out with three screws: idle, high speed, low speed. In the correct setting of the carburetor, the following signs indicate:
- The chain does NOT move at idle speed.
- The engine accelerates smoothly and quickly.
- The sound of the engine running is smooth, similar to the sound of a four-stroke engine.
Husqvarna carburetor adjustment algorithm and description
Husqvarna carburetor, adjustable in the same way as the carburetor settings on second-hand chainsaws.
The order of work is as follows:
- Husqvarna carburetor is factory set on muted dust.
- The engine starts and the saw warms up for a few minutes.
- By turning the screw (L) clockwise, the position is found at which the engine develops maximum speed, after which the screw must be unscrewed 1/4 back. If at the same time the chainsaw chain rotates, then it is necessary to reduce the idle speed by adjusting the position of the screw (T).
- The next stage is adjusting the power of Husqvarna at maximum speed and adjusting their number. To do this, the tachometer is connected to a running chainsaw, the throttle stick is squeezed out to full, after which the tachometer readings are checked. If the value of the maximum revolutions differs from the maximum number recommended by the manufacturer, then by changing the position of the screw (H), the tachometer readings are returned to normal.
The pressure in the float chamber, where the fuel is located before mixing, is practically equal to atmospheric pressure. However, a vacuum is created in the air channel, because of this, the fuel is drawn into the air stream. The more simply the damper is opened, the faster the air moves, and not the amount of fuel also increases. The engine speed increases. Adjusting the carburetor of the Husqvarna 142 chainsaw. This simplifies the principle of the carburetor.
For efficient, smooth operation of the tool, to get the maximum return, not in this case, economical fuel consumption requires tuning the carburetor of the chainsaw. Adjusting the carburetor of a Husqvarna chainsaw 142. Before adjusting, check the fuel NOT air filters. You need to be clean. On most chainsaws, adjustment is carried out with three screws: idle, high speed, low speed. In the correct setting of the carburetor, the following signs indicate:
- The chain does NOT move at idle speed.
- Engine accelerates smoothly NOT fast.
- The sound of the engine running is smooth, similar to the sound of a four-stroke engine.
Partner and Stihl chainsaws, their adjustments.
In Stihl NOT Partner chainsaws, the adjusting screws H NOT L set the proportion of air not gasoline in the mixture. When the screws are loosened, the mixture is enriched, the revolutions increase. Screwing in leads to a leaner mixture, not, respectively, to a decrease in engine speed.
Modern chainsaws have a complex system and consist of several main units, which periodically require maintenance and adjustment. In this article, we’ll talk about how to adjust the carburetor on a Husqvarna chainsaw.
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 difficult 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 from the 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. Responsible for limiting the air flow from the air filter to make it easier to start a cold Husqvarna chainsaw. At the moment when the operator cuts off the air supply to the carburetor with the help of the air damper, 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.
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 correctly, may stick, the fuel supply will stop, which will make the engine impossible to operate. Also, irregularities in the operation of the injector can become a prerequisite for air leakage into the main fuel chamber of the carburetor. In such cases, adjusting the position of the adjusting screws will NOT correct the situation, it will be necessary to repair or replace the unit.
By setting the quality and quantity of the mixture, as well as the number of revolutions of the crankshaft in idle mode, there are three adjusting screws installed in the carburetor body:
- Screw (L). Regulates the amount of fuel in the low and medium speed mode;
- (H). Responsible for traction at high speeds and their number;
- (T). Changes the position of the throttle valve, thereby regulating the amount of the fuel mixture entering the cylinder and the operation of the engine of the tool in idle mode.
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 Will not start. The reason for this is too rich a 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;
- The turnovers are kept at the same level after their decrease or increase by the operator. A stuck needle valve may be a prerequisite.
The factors leading to such changes can be the following:
- Strong vibration will damage the protective cover and the adjusting jets are unscrewed, changing the settings. In this case, it is possible to adjust the carburetor on the chainsaw.
- 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.
- 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, it proceeds to dismantle the carburetor, and then. To check the piston system.
What is the factory setting of the carburetor of a Husqvarna chainsaw?
In order for the chainsaw to start anyway, even if the setting is incorrect, the factory settings of the screws H and L are applied. Most Husqvarna chainsaws can be started by unscrewing both screws exactly one and a half turns. Only then can the position of the screws be changed in order to achieve the desired fuel consumption and maximum efficiency. It is regulated by XX also after THESE manipulations.
If you still have questions about adjusting the carburetor on the Husqvarna 137 chainsaw and the second models of this line. I recommend watching this:
The reason why the Husqvarna 142 chainsaw won’t start
If the Husqvarna 142 chainsaw does not start, there can be several events. Of the more common, the following can be distinguished:
- Damage to candles. To realize whether the candle is working properly, it is necessary to turn it out and inspect it. In this case, if the porcelain insulator has cracked, you see a burnt or warped electrode, you should immediately change the candle. Apart from having worked for several seasons, the Husqvarna 142 chainsaw asks for a parts inspection. Candles also develop their own resource, and in order to secure the operation of the saw, replace them with new ones.
- Carburettor clogged. During operation, fuel vapors evenly settle on the inner walls, forming a sticky consistency that can clog the carburetor, preventing the engine from starting. You will need to clean it with special detergents. We repair a Husqvarna 142 chainsaw, carburetor adjustment is always carried out with a warm engine and cleaned systems.
- Ignition coil defective. Before you decide to replace this part, make sure that the spark plugs correspond to the required technical condition.
Specifications
The Husqvarna 142 has a compact design with easy access to adjustments and fillers. The 4.6 kg tool is perfectly balanced for a comfortable grip.
The ergonomic shape of the handles provides a secure grip when performing difficult work. Built-in vibration protection system and low noise level contribute to high labor productivity and preservation of the operator’s operability when performing large jobs.
How to properly adjust the carburetor of a Husqvarna chainsaw with your own hands: General view
Modern chainsaws have a complex system and consist of several main units, which periodically require maintenance and adjustment. In this article, we’ll talk about how to adjust the carburetor on a Husqvarna chainsaw.
Chainsaw carburetor adjustment
Most chainsaw carburetors have three adjustment screws:
- L. Jet screw for low speed adjustment
- H. High Speed Adjustment Jet Screw
- Screw. T in partner and Husqvarna (in Stihl LA). Chainsaw idle adjustment
Screws H and L adjust the ratio of the mixture of gasoline and air, determined by opening the throttle valve of the carburetor. When the screws are unscrewed, the mixture is enriched, and the revolutions increase accordingly, when the screws are tightened, the mixture becomes leaner. Turnovers are falling.
The screw T (LA) is designed to adjust the idle speed. The basic setting of the chainsaw is made at the factory during the final test. The carburetor is usually adjusted for a richer (than optimal) fuel mixture. The factory setting must be maintained during the first hours of saw operation. Then (optional) a more precise carburetor adjustment is made.
We begin the adjustment by setting the idle speed, for this we turn the screw T (LA) counterclockwise, achieving a complete stop of the chain at stable engine speeds.
Humidity fine adjustment will need a tachometer and it is better to entrust it to specialists. over, in most cases it may NOT be needed.
We start setting up the tool with the L screw, then use the H screw and finally the T screw (LA).
We look for the highest idle speed, for this we slowly turn the screw L in different directions. After finding the position of the highest engine speed, it is necessary to return the screw L by 1/4 turn counterclockwise. If the chain rotates at idle speed, the screw T should be turned clockwise until it stops.
The screw H adjusts the power and speed. Adjusting the carburetor to a lean mixture leads to excessive speed, overheating of the engine and failure of the piston chainsaw.
We warm up the engine of the chainsaw at idle speed for at least 10 seconds and turn the screw H 1/4 turn counterclockwise. Let the engine run for about 10 seconds. Then we check the maximum engine speed with a tachometer. If the maximum speed does not match the passport, the operation should be repeated. When the mixture is too rich, the muffler starts to smoke, when the saw is too lean, it squeals and overheats.
We begin the adjustment by adjusting the idle speed, as already described above. The idle speed is set correctly if the engine runs smoothly at minimum speed and the chain does NOT rotate.
The carburetor can be considered adjusted if the engine accelerates quickly and sounds like a four-stroke at full throttle.