Husqvarna 128r Trimmer Carburetor Adjustment

Self-adjusting carburetor do it yourself impossible without preliminary work, knowledge of the theory, awareness of the fuel system. Carburetor repair annotation.

Do-it-yourself carburetor adjustment

Gas scythes, like all gasoline powered tools for the garden, are not difficult to maintain. It is possible and necessary to repair, configure without the help of others. For example, carburetor adjustment petrol scythes hands. A matter of 5 minutes.

A brush cutter carburetor is a unit in the power system. In it, like all carburetors, there is a process of mixing air and fuel (gasoline) for the upcoming supply to the engine cylinders.

The main thing in this process is the correct proportion of fuel and air, which is why the carburetor is regulated.

The main problems and malfunctions of the carburetor.

Strainer There are only two tasks with this element:

In order to find out the cause of the breakdown, the fuel filter cover is unscrewed to remove the strainer. If it just accumulated dirt, then washing with gasoline or blowing will help.

With visible damage to the strainer, it is imperative to install a new one. There may also be damage on the fuel supply pipe (during repair, check this element).

The carburetor starting device almost always does not work due to blockages. Use acetone or the same gasoline for flushing.

Blowing off carburetor parts with a blockage of compressed air is an acceptable and comfortable repair practice.

The throttle body, the bundles of carburetor parts, the intake or exhaust pipe. All of these parts are subject to depressurization. Probably you can check with a simple method. Smear the problem area with soap suds.

Arboretum carburetor device

The diffuser is equipped with fuel channels. Fuel is drawn from them by an air stream.

Outside the carburetor is installed:

  • Fuel pump;
  • Jet system;
  • System for adjusting the consistency of fuel with air;

Husqvarna 125R carburetor tuning without tachometer (temporary solution)

How to adjust carburetor,if you need to work, and the service with a tachometer is far away.

Adjustment carburetor lawn mowers Husqvarna 125, 128

Principle of operation carburetor petrol scythes

The throttle valve determines the amount of air for supply, and engine power directly depends on this.

Fuel is sucked into the carburetor system by a pump (its membrane). Then it passes through the fitting in the carburetor. Further, the fluid moves through the inlet and outlet valves of the pump. Filtered by mesh. The needle valve moves into the membrane chamber.

Phased operation of the device:

  1. Air supply to the tube with an air baffle (damper). The partition controls the intensity of the air flow.
  2. The fuel supply system must be narrowed by a diffuser to increase the flow rate.
  3. Gasoline through the float chamber and nozzle tube with narrowing. A camera with a float adjusts the temporary volume of gasoline. In the float chamber, the pressure level is neutral, and in the tube with narrowing is already low. Due to the pressure drop, fuel enters through the nozzle.
  4. The acceleration of the air flow contributes to the transfer of fuel (gasoline) and its atomization. As a result, an air-fuel mixture of the necessary proportion or density is formed.
  5. The air-fuel mixture enters the engine cylinder through the fuel pipe.
Husqvarna 128r Trimmer Carburetor Adjustment

The level of air density in the system depends on the area of ​​the open air damper. The wider the flap is open, the greater the fuel consumption and power.

Simply put, adjusting the carburetor on the brushcutter is creating the optimal fuel mixture due to the correct air supply.

How to adjust a carburetor on a brush cutter

Further carb adjustment do-it-yourself brushcutters performed by adjusting screws. There are three of them:

Right (L). Adjustment of the fuel mixture for low revs.

Need to find the maximum idle speed. To do this, slowly turn the screw (L) to the right and left.

To adjust, turn the screw a quarter of a turn necessarily counterclockwise.

Bottom (T). Is responsible for adjusting the engine at idle.

  • Clockwise. Increase;
  • Counterclockwise. Decrease.

For proper adjustment of idling, it is typical:

  • Steady work of the cold engine;
  • Not overestimated speed of the hot engine;
  • A large headroom for the trimmer head;
  • Stable operation of the engine when changing position (sharp rise or descent of the knife).

Left (N). Adjustment of the mixture at high speeds. (The screw is configured last).

The left-hand screw (N) determines the general adjustment of the maximum speed, engine power, temperature and gas mileage.

Customization carburetor brushcutters with the last screw is performed as follows:

  1. Open the throttle to full, while giving out full throttle. Turn the screw clockwise until the speed drops (in this case, they are oriented by ear).
  2. Turn the screw as slowly as possible counterclockwise until the engine runs unevenly.
  3. Then turn back quite a bit, barely hearing a stable, smooth operation.
  4. For a more visual application of skills, it is more convenient to consider the work of an experienced user:

Interestingly, from the point of view of the author of the, the setting (its correctness) is determined by the color of the candle, and not just by the speed and stability of the engine.

The correct setting of the carburetor with your own hands in this case is the combustion of the fuel mixture without residue, the color of the candle should be light brown.

Carburetor Adjustment Husqvarna 128r Gas Cutters

Adjustment Summary carburetor petrol scythes.

Carburetor Adjustment and Repair gas mowers

The trimmer does not belong to complex household appliances, so most of its breakdowns are mechanical in nature and can be successfully repaired with their own hands. Cleaning the carburetor of the Honda izy lawnmower. Even if the engine fails for serious reasons. Damage to the piston ring, for example, repair comes down to replacing the part.

But even with a relatively simple design, such a part of the device as a carburetor needs to be adjusted.

Principle of operation

A carburetor is a power system module in which liquid fuel and air are mixed before being fed into the engine cylinders. Depending on the tool and its operating mode, mixing and feeding are adjusted accordingly.

The device of the carburetor is the same for almost all cases. It belongs to the category of float devices. The latter provide stable parameters of the finished mixtures.

The principle of operation of the module is as follows.

  • Air enters the body of the tube with an air damper. The latter enhances or reduces air flow depending on its position.
  • In the area where the hole for supplying gasoline is formed, the tube has a constriction. A diffuser. Here the flow rate increases.
  • Fuel from the float chamber through the nozzle is fed into the tube. The carburetor device for lawn mowers. Carburetor tuning The float level determines the amount of fuel supplied. Since the pressure in the chamber is normal and low in the tube due to the greater dilution of air, gasoline is sucked through the nozzle.
  • Accelerated airflow picks up fuel and atomizes it, forming an air-fuel mixture of the desired density.
  • The mixture is sucked into the cylinder through a pipe.

The more open the air damper in the tube, the higher the density of the air flow, which means that more fuel enters the cylinder. Setting up the carburetor of the brushcutter is reduced to setting such a ratio of dampers at which the density of the fuel mixture becomes optimal.

Signs of imbalance

Carburetor debugging is necessarily carried out in the manufacture of the apparatus. As a rule, the owners will only learn about the need to adjust the fuel supply with their own hands after serious enough failures, during the correction of which the module was removed and, for example, cleaned.

Signs of a failure in the settings are as follows:

  • It starts, but the engine stalls right away. Since the engine can only work when a certain amount of gasoline is supplied, if the fuel is too “poor”, that is, when the feed channel is blocked, the motor will stop;
  • Too much fuel consumption, a lot of exhaust gases. The result of incomplete combustion of the mixture. In this case, on the contrary, there is too much fuel and the mixture turns out to be excessively dense.

Carburetor adjustment for the Husqvarna 125, 128

Husqvarna 125R carburetor tuning without tachometer (temporary solution)

How to adjust carburetor,if you need to work, and the service with a tachometer is far away.

Carburetor Stihl, Makita, Husqvarna and others are adjustable using the adjusting screws. Sometimes the reason for the disorder of the work is a violation of fixation. Due to vibration or damage to the protective cap. Such a breakdown can be detected simply by trying to turn the screw a little: if the fixation is not rigid, it is worth checking the setting.

DIY carburetor adjustment

The configuration of the module does not apply to repair and replacement of spare parts is not required. Cleaning the Honda Lawnmower Carburetor. In this case, a gas trimmer carburetor repair kit will not be needed.

There are three screws for debugging:

  • L. Is regulated first, since it is responsible for supplying fuel at low speeds;
  • H. He is responsible for the supply of gasoline at high speeds, as well as for fuel consumption and temperature;
  • T. With its help idle debugging is carried out.

There are options, as a rule, this is a Chinese petrol scraper carburetor, when there is only one screw left for debugging on the case. For setting idle speed. This does not mean that the module is automatically configured. It means that it will be difficult to carry out even a type of repair such as debugging. In the photo. The adjustment of the carburetor of the Chinese trimmer.

  1. Setting up the module is carried out only when the engine is warm: for this, the device is first turned on for 10 minutes. Carburetor adjustment If the mowing head rotates at idle, then proceed with debugging immediately: turn screw T counterclockwise until the rotation stops.
  2. Adjustment starts with screw L. The screw rotates left and right until it finds its position at which idle speed does not become maximum.
  3. Then turn the screw ¼ turn counter-clockwise. This will be his working position.
  4. Idling must be adjusted by turning counterclockwise to increase the speed and clockwise to decrease. Its debugging consists in the achievement of such a mode in which a sufficient number of revolutions is made before the mowing head begins to rotate. In this case, the engine must work stably in different positions.
  5. The position of the screw L is determined last. At maximum speeds the trimmer should not work for more than 10 seconds. The throttle opens, the screw turns clockwise, very slowly, until a decrease in the number of revolutions is established by ear.
  6. Then, the screw also rotates slowly counterclockwise until the motor starts to malfunction. Then the screw is turned back clockwise until the engine starts working again normally.

If there is a tanometer, and if the recommended revolutions are indicated in the product passport, the correction can be made more accurate, focusing not on the ear, but on the readings of the device.

6 post comments Adjustment and repair of a carburetor

Please clarify. In the adjustment section of clause 5, screw L error? Should I read screw A? Thank you

Tell me the initial position of the screws H L LA


Tell me the initial position of the screws H L LA

Husqvarna Chainsaw Carb Adjustment

Modern chainsaws have a complex system and consist of several main components, which periodically require maintenance and adjustment. In this article, we’ll talk about how to adjust the carburetor on a Husqvarna chainsaw.

Important. An experienced electrician has leaked the secret to the network how to pay half the price of electricity, the legal way. Read more

When does the Husqvarna chainsaw carburetor require adjustment

There are many problems that can be solved by adjusting the carburetor. Husqvarna chainsaw carburetor adjustment is necessary when a malfunction occurs such as:

  • Increased idle;
  • Heavy smoke during tool operation;
  • Difficulty starting a cold or hot engine;
  • Lack of traction and lower maximum revs.

This is by no means a complete list of problems that can be solved by tuning the Husqvarna carburetor. In some cases, adjusting the quality and quantity of the fuel mixture is carried out after an overhaul of the engine or in the process of scheduled maintenance of the chainsaw.

The manufacturer Husqvarna AB recommends adjusting the carburetor before and after the break-in.

The device and principle of operation of the Husqvarna carburetor

To successfully set up a Husqvarna chainsaw carburetor, you need to know its device 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 with oil, as well as a diaphragm, a needle valve with a rocker. Their joint work allows metering the fuel supply to the main chamber and two shutters.

One of the dampers is designed to adjust the fuel supply to the cylinder when pressing the gas, it is called the throttle, the second is responsible for restricting the air supply from the air filter to facilitate the start of the Husqvarna cold chainsaw. At that moment, when the operator shuts off the air supply to the carburetor with the help of an air damper, the fuel mixture is depleted and its supply to the cylinder is increased, due to which the chainsaw starts up much easier than when the cold start is carried out in normal mode.

An injector valve is involved in the operation of the Husqvarna carburetor, which atomizes the fuel and prevents air from entering the main chamber. Often problems when working with a saw can be caused by defects in this particular element. For example, a valve, if the chainsaw is not stored properly, can stick, fuel supply will stop, which will make the engine impossible. Also, malfunctions of the nozzle 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; repairs or replacement of the assembly will be required.

For adjusting 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). Adjusts the amount of fuel in 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 fuel mixture entering the cylinder and the engine’s engine idling.

Screws (L) and (H) cannot be adjusted without specific knowledge and experience. Incorrect adjustment of the quality and quantity of the fuel mixture can cause the engine to stop working or malfunction, which will lead to its rapid deterioration or even jamming.

Tools necessary for work

Before setting up the Husqvarna carburetor, you need to take care of the availability of all the tools that may come in handy. To carry out this type of work yourself, you will need:

An ordinary slotted screwdriver is not suitable for adjustment, because the adjustment screws on Husqvarna chainsaws can have a different cross-section. You have to purchase a special one, this is the peculiarity of repairing Husqvarna chainsaws, they did everything so that the saw could be repaired only in a specialized Husqvarna service.

Husqvarna carburetor algorithm and description

Husqvarna carburetor, is regulated similarly to how carburetors are adjusted on chainsaws from other manufacturers.

Immediately before the adjustment, it is necessary to conduct a complete diagnosis of the saw and make sure that there is no difficulty in supplying fuel and air intake into the crankcase of the chainsaw. You must also make sure the air filter is clean and replace it with a new one if necessary.

The procedure for the work is as follows:

  1. Husqvarna carburettor factory settings are set on the muffled saw.
  2. The engine starts and the saw warms up for several minutes.
  3. By turning the screw (L) clockwise, there is a position at which the engine develops maximum speed, after which the screw must be turned back 1⁄4. If at the same time the chain of the chainsaw rotates, then it is necessary to reduce the idle speed by adjusting the position of the screw (T).
  4. The next stage is the adjustment of the power of Husqvarna at maximum speed and the adjustment of their number. To do this, the tachometer is connected to the wound chainsaw, the throttle stick is squeezed to full, after which the tachometer readings are checked. If the maximum speed value differs from the maximum quantity recommended by the manufacturer, then by changing the position of the screw (H), the tachometer readings are normalized.

Adjustment nuances

After adjustment, the chainsaw should easily gain and lose speed, work stably at low and high speeds. If the saw chain rotates at idle after adjusting the carburetor control screws, this is a sign that the setting is incorrect and that the position of the screw (T) needs to be adjusted.

Also, when adjusting the Husqvarna carburetor, it is worth considering 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 incorrect adjustment is a strong smoke during the operation of the saw, which indicates a large amount of fuel entering the combustion chamber. If this situation arises, adjust the position of the screw (L).

Factory settings

The factory default settings for the Husqvarna carburetor are the position of the screws (H) and (L), in which a working chainsaw must be 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 in the standard position, then start the chainsaw and make an accurate adjustment of power, the number of maximum revolutions and idle revolutions.

DIY carburetor repair

If during the complete diagnosis of the Husqvarna chainsaw, carburetor defects were detected, some of them can be eliminated without contacting the Husqvarna AB service center. For example, you can independently:

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

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

Also, if you have some experience, you can try to restore the faulty valve-nozzle, but you cannot guarantee a positive result when trying to restore the nozzle, 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. After that, unscrew the screws securing the carburetor.

Dismantling the carburetor body for repairs is quite simple. The cover of the main chamber is held by four screws, which can be removed using a conventional screw, the cover of the fuel pump is fixed with one wide screw.

Below is a, watching which it becomes clear how it is possible to repair a carburetor without contacting a Husqvarna service center.


Work on setting up or repairing a carburetor on Husqvarna chainsaws can be completed without any specific experience. In order to do everything right, you must follow the algorithm and have a minimal set of tools. It is also worthwhile to evaluate your strengths in advance and not risk it if you do not understand anything at all in the technique. Believe me, sometimes it’s better to pay a small amount to the master than to spoil the instrument by self-regulation.

We repair the Husqvarna 128R trimmer

I decided to write a couple of lines about the Husqvarna 128R braid. I bought this tool 2 years ago. Well, I think the tool is eminent, I will mow and mow. Not heavily loaded 18 acres plus around the site.

He worked with her in the mode: he spent the tank and allowed it to cool for 20 minutes. Over the summer, 3.4 times the full mileage of the site and the surrounding area. Poured Husqvarna Oil. Could not get enough, as the plant with a half kick. This year, she stopped pulling and started badly. I even stopped using it especially, as I suggested that nothing lasts forever, and perhaps she was already tired of me. I can try to do it myself, I thought, and went for the tool. I’ll start by cleaning the carburetor, I suggested, and did not think for a long time to climb into the bowels of the scythes.

The first thing I did was to remove a candle like norms, clean it, it’s better to replace it, but it wasn’t.The zero-idle result simply stalls. I take off the candle and check the spark. A spark that is, that is not. He began to probe and experiment. It turned out the tip of the high-voltage wire just fell off. Well, I think I don’t want to look for a new wire, time and money must be mowed. Soldered a vein of a high-voltage wire to a tip, I collect, anticipating a victory. But things are still there. Perhaps a spark jumped in the damaged wire and did not significantly affect the work. I disassemble again to remove and clean the carburetor of the brushcutter, and he just hangs out. From vibration just unscrewed. It turns out during a set of revolutions the air entered the slot, impoverished the already poor mixture of gasoline and was suffocating, but at idle it seemed to rattle. Here you have the American quality assembled in China. These bolts under the asterisk.

When disassembling, you need a screwdriver for interchangeable tips, asterisk tip and hexagon. Understands hemorrhoids. But apparently this is the key to reliability. Carefully and leisurely everything will turn out.

Air filter chamber. The filter was washed in kerosene. He became like new. Then it must be “moistened” in any oil. I will not describe the assembly of the braid. The main thing is not to lose the bolts and not mix them up. Different bolts with small and large threads. Large in plastic. Shallow on metal. The whole repair took about 2 hours. Good luck!