How To Adjust Carburetor On Husqvarna Trimmer

adjust, carburetor, husqvarna, trimmer

Fuel mixture preparation

When operating a chainsaw, a fuel mixture of gasoline and oil in a ratio of 15: 1 by volume should be used, that is, 1 liter of oil should be added to 15 liters of gasoline and the mixture should be thoroughly mixed. The amount of gasoline and oil in the fuel mixture is shown in this table:

ATTENTION! Application of oils: Lukony-2T; TNK-2T OIL: AZMOL Sport 2T GD “and others, and waste oil in the fuel mixture will lead to failure of the connecting rod needle bearing.

When carburetor adjustment is necessary?

The reasons why this unit will need to be adjusted can be listed for a very long time.

Among the main malfunctions are the following:

  • Increase in idle speed;
  • The appearance of a large amount of smoke during operation;
  • Deterioration of starting properties;
  • Insufficient tool power when cutting.

This is not a complete list of all known faults. Sometimes a procedure such as adjusting the carburetor on a Husqvarna chainsaw may need to be done after a major overhaul of the power plant or after maintenance.

The developers of the Husqvarna 137 write in the passport that the carburetor adjustment must be carried out before and after running in the tool.

What is the factory setting of a Husqvarna chainsaw carburetor?

In order for the saw 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 other models of this line, I recommend watching this

Adjusting the carburetor of a Husqvarna chainsaw

Like all other saws, the husqvarna has the same carburetor adjustment algorithm. Therefore, the instruction will be relevant for other tools and models of chainsaws such as Husqvarna 142.236.

Before starting work, make sure the air filter is clean and all other components are working properly. The fuel supply to the float chamber should work without interruptions, and the ignition system is configured correctly and has a fresh spark plug.

  • Set the carburetor to factory settings. This must be done with the engine stopped.
  • Now you can start the engine and be sure to warm it up for a few minutes. Adjustment of the XX carburetor of Husqvarna 137 is carried out only on a warm engine.
  • Turning screw L clockwise, you need to set the highest speed of the crankshaft, then turn back a quarter of a turn. Adjust the speed of the crankshaft with the screw T so that the chain does not rotate. It should not be set in motion without pressing the accelerator.
  • Now you need to set the maximum speed and their power. It is enough to connect the tachometer to the ignition system and set the maximum possible speed using the accelerator. Compare them with your passport data. If they differ, then unscrew or tighten screw H. By changing the range, you can create restrictions to make the saw work efficient and save the motor resource.

What is responsible for the air supply

Two dampers are responsible for the air supply, installed on the diffuser chamber. The first can regulate the amount of air at the moment the accelerator is pressed and is called the throttle, and the second ensures the limitation of the air supply at the moment when the chainsaw is cold started. To facilitate starting, the damper is closed, which means that the mixture becomes rich, as it is saturated with a large amount of fuel. It is easier to work in this mode, but since it increases fuel consumption, this mode is not applied throughout the entire operation. The saw is worn out.

A check valve injector is used to spray fuel into the cylinders.

The principle of operation is simple: it restricts the return of the mixture back to the chamber. All the main malfunctions of chainsaws, most often, manifest themselves when this mechanism does not work properly.

  • The most common mistake is storing the instrument for too long. The fact is that with prolonged inactivity, the valve sticks and either fills the cylinder with fuel, or simply does not open.
  • The second problem is an increase in the amount of air in the mixture, caused by its suction from the outside when the valve does not work properly. It is no longer possible to regulate here, since in this case only valve repair or its replacement helps, since the saw will not react to the adjusting screws.

Unlike the car, the carburetor setting of the chainsaw provides for three adjusting screws that are responsible for the quality of the mixture, the amount and nominal speed of the crankshaft of the Husqvarna engine:

  • screw L. is designed to adjust the number of revolutions when working in medium modes and regulates low revolutions;
  • Screw H. adjusts the number of high revolutions and thrust of the installation;
  • T. designed to adjust the total amount of fuel and adjust the operation of the throttle assembly.

It is not recommended to touch the first two screws without special skills. The problem is that if you configure them incorrectly, the carburetor will not be able to start the engine, or even start it in the wrong operating modes. Such adjustment of the screw can lead to its early wear and failure. This principle is embedded in many devices.

No table lists the settings parameters. Therefore, you should not look for these data in special literature, but only strictly follow the instructions. The table in the passport has only informational value regarding the characteristics of the engine.

What you should pay attention to?

Once the Husqvarna carburetor adjustment is complete, you need to ensure that the engine is stable and the saw can easily pick up and drop the required speed. It is considered abnormal to rotate the chain at idle speed, therefore it is necessary to re-adjust its connection with the clutch using the screw H.

Do not forget that the assembly is not immediately set up: you need to wait a while, as the Husqvarna chainsaw does not immediately respond to changes in the position of the screws. This time can range from 5 to 15 seconds. This time does not prescribe the table, so you can only find out experimentally.

If, after adjustment, a huge amount of smoke appears during operation, then you need to adjust the supply of the fuel and oil mixture. For these purposes, rotate the screw L.

How to adjust the carburetor on a Husqvarna 137 chainsaw

The chainsaw is a great helper for any man living in his home. The chainsaw device is a complex system that requires careful maintenance and requires increased attention. Today you will learn how to adjust the carburetor of a Husqvarna 137 chainsaw with your own hands in the garage.?

Mechanic at home: adjusting the carburetor of a chainsaw with your own hands

Any internal combustion engine requires periodic maintenance, It doesn’t matter if it is the engine of a simple moped or a powerful multi-ton tractor. Such a tool as a chainsaw was no exception. After all, it is equipped with a single-cylinder two-stroke internal combustion engine, which also requires serious maintenance, although it is much easier to perform the necessary actions here. In today’s article we will talk about how to adjust the carburetor of a chainsaw with our own hands, find out how difficult it is, and figure out whether you need to be a professional mechanic to do this kind of work.

Determining the need to adjust the carburetor on a chainsaw

Before you start adjusting the carburetor on a chainsaw, you need to make sure that it is generally required. It would seem an absurd phrase. However, in 90% of cases, when an inexperienced craftsman considers such an action necessary, the unstable operation of the instrument is associated with other reasons, including:

  • problems in fuel lines and filter. blockages, depressurization;
  • malfunction of the exhaust system;
  • clogged or damaged air filter;
  • unstable operation of the ignition system;
  • violation of the tightness of the crankcase of the internal combustion engine.

Only if these problems are excluded, and the engine is unstable, it is safe to say that carburetor adjustment is required.

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How does a chainsaw carburetor work, on what principle does it work

Modern car engines are no longer equipped with a carburetor. Meanwhile, before, almost every driver knew how to adjust it. Today, chainsaws with injection engines have already begun to appear on sale, however, carburetor models will hold the palm for a long time, because their cost is 5-15 times lower than that of the modernized version.

The carburetor consists of several main parts:

  • aluminum body;
  • diffuser and air damper at the inlet;
  • nozzles (valves for adjusting the fuel supply);
  • sprayer (it is he who provides injection);
  • fuel (float) chamber.

The principle of operation of a chainsaw carburetor is quite simple. Fuel is supplied continuously, and its quantity is regulated by jets. Air enters through the air damper due to the air vacuum generated by the piston. The diffuser mixes fuel and air. It is this fuel-air mixture that enters the cylinder, forcing the engine to work.

How to adjust the carburetor on chainsaws

To understand how to properly adjust the carburetor on a chainsaw, you need to see it, and therefore we invite the reader to pay attention to the example below.

To make the adjustment, you only need a slotted screwdriver, however, it will not be possible to perfectly fine-tune the carburetor without a tachometer (of course, if the person is not a minder or a professional driver with experience). Now let’s try to understand how to set up the carburetor in a given situation.

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 “I know everything” series tries to get into the settings with hands that do not grow from the shoulders. In this 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.

With regard to the idle screw, the throttle must first be completely closed (screw T unscrewed). 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

In order 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 video.


Now we need to get the needle.

To do this, unscrew the bolt on the mechanism, holding it with your finger. The fact is, there is a spring there and a careless action will lead to the fact that it will be lost.

We take out the needle, see photo and spring.


In addition, the bubble button for manual fuel pumping may fail. The impact of gasoline on it leads to the fact that during prolonged operation, the rubber corrodes and it begins to stick together or, under the influence of low temperatures, for example, during storage, it bursts. The button should also be replaced if necessary. In addition, her cost is small and will not affect the size of the repair budget in any way.

Based on the foregoing, it can be concluded that there are only three main carburetor malfunctions: clogging of channels, contamination of the fine filter and failure of components. In the first two cases, cleaning is enough, and in the third, a repair kit will help.

Step 1

Another particle of dirt can get stuck under the needle. See photo. This will also cause lawn mowers to fail.

Important! Never use needles, pins or wires when cleaning the carburetor. Even the slightest scratch will disable the carburetor. It will have to be changed entirely.

Assembling the carburetor

Assembling the carburetor for lawn mowers is a snap. All steps must be performed in reverse order:

In order for the chainsaw to work properly, you need to carefully carry out work on adjusting the carburetor in exact accordance with their sequence. Here’s what it looks like on how to adjust the carburetor on How to adjust the needle. If there are any irregularities in the operation of the device, it is necessary to completely disassemble it yourself. How to adjust the carburetor With the H screw, we set the speed as on different lawn mowers. In most cases, replacement of any parts that have become unusable is required.

With a constant check of the quality of carburetor settings and the implementation of timely actions to improve its operation, problems with the chainsaw do not arise.

About which chainsaw to choose. read here.

Step 0

Install the main membrane.

Chainsaw air filter

Before adjusting the carburetor, you need to prepare the device:

  • The engine warms up, that is, it starts about 10 minutes before the repair, and turns off when you start work (see how to start the chainsaw).
  • The air filter is checked and washed.
  • Stop the chain by turning screw T as far as it will go (see chain oil).

To carry out a safe repair, you need to prepare a flat surface where you can carefully position the device, and turn the chain in the opposite direction. We need a tachometer. It determines the presence of a violation in the operation of the carburetor. When the screws are turning, the sound should be perfect and absolutely even. If squealing notes are noticed, then the mixture is oversaturated.

Dismantling the carburetor if it is necessary to check or repair components

The device of different models of carburetors is almost the same, so when working with them, you can use the standard scheme. All elements must be removed carefully, and then laid out in the order below so that you can successfully place the items in place at the end of the repair work.

Removing the top cover

  • The top cover is removed. To do this, unscrew the 3 bolts holding it in a circle.
  • The foam rubber can also be removed, since it is the upper part of the filter that conducts air.
  • The fuel hose is removed.
  • The drive thrust is output directly to it.
  • The cable end is detached.
  • The petrol hose can be completely removed by systematically pulling it off the fitting.

To finally prepare the carburetor for overhaul or replacement of the smallest parts, you need to carefully disconnect it from the main system. Sometimes further disassembly is required. Unscrew the components carefully and fold the fasteners in groups, as these small parts are easily lost.

Adjusting the carburetor trimmer

lawn mowers have long been included in our lives as a very useful tool and a great alternative to the usual scythe. lawn mower and lawn mower are the same tool. And trimmers are gasoline, and there are electric. In this case, we will focus on gasoline. This unit is quite simple to operate, but it has its own characteristics. lawn mowers are equipped with an internal combustion engine. The carburetor for lawn mowers is a very important part of the tool. The main task of the carburetor is to ensure the flow of air-enriched fuel into the engine cylinder. The most important thing here is to maintain the balance of fuel and air. The article will tell you about the signs indicating the need for adjustment, how to set the carbrator on the trimmer.

It is allowed to adjust the carburetor trimmer on your own, having previously studied the device of the unit. As a rule, a detailed description of the components of the tool is in the instruction manual. An experienced craftsman can even determine by ear that there are flaws in the work of lawn mowers. The sound of the motor, when properly tuned, should be perfectly smooth. If you can clearly hear squealing sounds, then the mixture is oversaturated.

Cases indicating the need for adjustment:

  • If a fuel mixture of a different composition is used;
  • With a long break in operation (the lawn mower lay idle for a long time, and even before the new season after winter);
  • After completion of the equipment break-in process (usually after using 4-5 liters of fuel)
  • When weather conditions change (this item is relevant for);
  • Poor engine starting
  • If fuel consumption has increased sharply;
  • An increase in the amount of exhaust gases;
  • Slow set of revolutions by the engine;
  • If the fuel mixture does not flow.

Fuel supply adjustment

Idle speed adjustment

Following the adjustment of the fuel supply, we take up the idle speed adjustment. To do this, the corresponding screw must be adjusted so that the engine runs slightly accelerated at low revs. But it is necessary to monitor the immobility of the reel with fishing line and knives. Before starting their movement, there should be a few turns in stock. The movement of the spool and knives can subsequently lead to rapid wear of the clutch. Noticing that the engine does not start well, you need to increase the number of idle revolutions. As the revs increase, the fuel mixture is saturated with air, which leads to a loss of power.

The main signs of correct idling:

  • Stock of turns for the trimmer head;
  • Uninterrupted operation of the engine even when changing position (sharp rise or fall of the knife);
  • Quiet operation of the engine on a cold run;
  • No increased rpm of a hot engine.
adjust, carburetor, husqvarna, trimmer

Husqvarna 125B service and carburetor adjustments

Adjustment at maximum speed

Further, to fully tune the carburetor, the lawn mowers need to adjust the maximum rpm. It will not be superfluous to look into the instruction manual of the tool and see the maximum value of the revolutions. Most accurately, this number will help determine the tachometer. If such a device is not at hand, we tune it by ear. Having barely determined the maximum rpm value by ear, we begin the adjustment. The screw for limiting the maximum speed will help in this matter. Check the operation of the engine at maximum speed. If it is necessary to reduce the speed, it is necessary to loosen the fixing nut and unscrew the screw. If the revolutions are too high, then you will need to screw in the screw. These steps must be done in order to protect the engine from overheating. It is necessary to turn the screw until a clear smooth engine operation is established.

After the work done, if everything is done correctly, the stable operation of the tool is ensured.

This will be understood by the following signs:

  • The cutting element will stop rotating at idle speed;
  • Fuel consumption will decrease.

Carburetor setting lawn mowers with three adjusting screws

Place the mower on a flat, stable surface before starting work. Turn the chain in the opposite direction. Lawn mowers are available with two and three adjusting screws. Tools made in China are most often equipped with two screws. Consider adjusting the carburetor of a lawn mower with three screws.

Carburetor setting lawn mowers with three adjusting screws

The air filter must be rinsed before proceeding with the carburetor adjustment of the lawn mower. Cleaning is carried out with water with the addition of detergent or soap, and if necessary, install a new one. Often, blockages are to blame for poor carburetor performance. As a preventive measure, it is recommended to clean the filter after every 10 hours of tool operation. Do not forget to check the condition of the candle, if there is carbon deposits, you need to clean it. Candles are consumables and have their own resource. To ensure good engine performance, lawn mowers need to be replaced periodically. Next, we evaluate how well the carburetor is attached to the cylinder-piston group. After finishing the preparatory manipulations, you need to start the engine. Let the engine run for 5-10 minutes. Then you need to identify how many adjusting screws on your instrument.

The petrol trimmer has the following adjusting screws:

  • Idling adjustment screw;
  • Fuel mixture adjustment screw
  • Maximum speed limiting screw.

Carburetor setting lawn mowers with two adjusting screws

Adjusting the carburetor for two-screw lawn mowers is much easier than described in the first option. However, it is worth noting that this setting is less accurate. Before starting the configuration, you must remember the factory settings of the lawn mower. After a while, the engine starts and runs for several hours. Although on some instruments, 10-15 minutes of work is enough to set the necessary parameters.

Carburetor setting lawn mowers with two adjusting screws

First you need to start the engine at low speed. If, during operation, the chain moves along the bus, then this is not the norm. You need to adjust the screw so that the chain stops moving.

Next, you need to go to medium speed. After which the engine can smoke. The adjusting screw will also help eliminate this nuisance. By tightening it harder, the fuel mixture, which is less enriched, will begin to flow into the engine. After that, the smoke will disappear. But the turnover will increase. Adjustments must be made until smooth, precise operation without jerking is achieved.

After all the necessary settings have been made, it is necessary to let the trimmer work in real conditions for more than one hour. After a while, it would be good to check if all the components are working correctly. If deviations are found, they need to be eliminated.

An indicator that the adjustment has been completed successfully will be residual combustion of fuel and a slightly brownish color of the plug. The color of the carbonized candle is darker.

Adjusting the carburetor for lawn mowers is a very important preventive measure that must be carried out every time such a need arises. As described above, such a need may arise quite often. By the way, screws that have loosened from vibration can also serve as a reason for tuning. In order for the tool to serve for a long time, you must always follow the instruction manual for the lawn mowers, use the correct fuel mixture.