DIY gasoline trimmer carburetor repair

In detail: DIY gasoline trimmer carburetor repair from a real master for the site my.housecope.com.

An indispensable tool for a modern summer resident or owner of a private house is a petrol cutter, which allows you to effectively and efficiently put the adjacent territory in order. The period of active use of brushcutters is in late spring until October. Modern units are equipped with powerful and durable internal combustion engines, reinforced transmission and main components. Despite this, physical wear, manufacturing defects or improper operation lead to failure of the trimmer. In order to repair the trimmer with your own hands, you must have at least basic knowledge in the field of technology and little experience in repairing it.

The main unit of any gasoline tool is the internal combustion engine (ICE), which, through various methods, transmits torque to the actuator. In a modern petrol cutter, a duralumin rod (pipe) is used as a transmission element between the engine and the trimmer head, inside which the drive shaft is located.

Thanks to the high-revving engine, the line speed can reach 13 thousand revolutions per minute, depending on the manufacturer of the scythe. In order to exclude mechanical and thermal damage to the gearbox, a special hole is provided in its housing for the introduction of grease in the form of ointments. To make the headset easier for the owner during long-term work, all brushcutter models are equipped with a durable shoulder strap.

Regardless of the manufacturer, almost every model comes with a line and steel knives.

Video (click to play).

The cross-section of PVC trimmer line can vary from 1.5mm to 3.0mm.

Made of durable polymer, it is subject to intense wear and tear during mowing. Therefore, from time to time it is necessary to check the presence of a fishing line in the head and, if necessary, replace it. It is recommended that you purchase an extra bobbin to quickly replace it with a spool with no line.

ICE trimmers on the market today are equipped with a D-shaped, U-shaped or T-shaped handle, where the main controls of the unit are located. For example, in a braid with a U-grip, the throttle key and stop / start toggle switch are located on the right grip. In the D-shaped version of the handle, the throttle control button is located directly on the rod.

Due to the presence of many components and parts, repairing a trimmer with your own hands means eliminating breakdowns that prevent its normal operation. It should be noted the most basic malfunctions of gasoline streamers:

The trimmer motor is not picking up speed;
Breakdown of the cylinder-piston group (CPG);
Ignition malfunctions;
There is no connection between the internal combustion engine and the trimmer head;
Mechanical knocking during unit operation.
Repair of the central piston group petrol cutters

The main unit of any internal combustion engine is the cylinder-piston group (CPG), which can fail due to wear of parts of parts or poor quality of the fuel mixture.

Lubrication of rubbing units in a petrol cutter is carried out by adding a certain proportion of oil to gasoline. This process can be disrupted due to old oil precipitating out. In this situation, when the trimmer is started, the motor overheats and in a matter of minutes the most expensive breakdown occurs. To eliminate the malfunction that has arisen, a complete replacement of the CPG will be required, namely: the piston, oil seals, cylinder and piston rings.If you are not an ICE repair technician and do not have experience working with technicians, then you will hardly be able to fix the engine without the help of a specialist. Details on the stages of piston trimmer repair can be found here.

If the ignition of the petrol mowers fails, the spark on the candle disappears and, as a result, the fuel mixture does not ignite.

Spit spark plug design

In this situation, it is quite important not to rush to replace the coil, since the cause of the breakdown may lie in the lack of contact in the switch on the control handle.

An important point when troubleshooting the trimmer ignition will be the diagnostics of the section, where the distance between the side and center electrodes should be 0.5-0.7 mm. In addition, it is necessary to pay attention to the steel O-ring on the spark plug, the loss of integrity or deformation of which can lead to etching of air from the combustion chamber and, as a consequence, reduce the power of the streamer.

Ignition flywheel with coil

If the replacement of the check of the electrical circuit, the spark plug and its contacts did not give positive results, then you should pay attention to the trimmer ignition module, namely the clearance with the flywheel. Regardless of the design features and the manufacturer of the brushcutter, the distance between the ignition coil and the flywheel should be no more and no less than 0.2 mm. To restore the optimal value of the gap, you will need to loosen the coil mounting bolts and set the trimmer ignition with a special measuring probe.

A clear sign of a malfunction of the engine power system is the absence of traces of the fuel mixture on the spark plug electrodes, which may be associated with the following defects:

Trimmer Fuel System Components

due to a clogged hole in the gas tank, a vacuum is created, which prevents the normal flow of gasoline into the carburetor;
due to the poor quality of the fuel and the ingress of foreign particles, the fuel filter installed in the tank is clogged;
non-flow of the mixture into the combustion chamber as a result of a clogged carburetor.

You can quickly determine the cause of the malfunction by dismantling the fuel hose leading to the carburetor. If the fuel mixture flows out in a thin stream, then you should pay attention to the carburetor. If there is no jet, it is necessary to clean the breather with a thin needle (a small hole in the gas tank cap) or replace the fuel filter.

If fuel enters the carburetor, it must be cleaned or adjusted. Adjusting the carburetor trimmer means restoring optimal fuel mix.

Trimmer carburetor with adjustment screws

To do this, pay attention to three adjusting screws: maximum speed (H), minimum (L) and idle speed (LA). To start the adjustment, you need to fully tighten the screws H and L and loosen one turn each. Then we start the braid and let it warm up for 10 minutes to adjust the power system in operating mode. After warming up the internal combustion engine, press the gas supply button until it stops (12,000 rpm). We restore the idling mode by unscrewing the screw LA. As soon as the trimmer head starts rotating, tighten the screw until it stops.

One of the common faults of the petrol mowers is the incorrect operation of the internal combustion engine, namely the drop in power with increasing speed (the scythe stalls).

The reason for this is that the exhaust system is clogged with burnt oil particles. Often manufacturers make mufflers prefabricated and cleaning is quite simple. If the design of the spark arrester is non-separable, then it must be placed in water with detergents, and then dried with an ordinary or industrial hair dryer. Frequent clogging of the exhaust system indicates non-observance of the proportions of oil and gasoline.

Modern technologies and equipment make it possible to produce the best and optimal technical solutions that become effective assistants in the arrangement of a summer cottage or a personal plot. The green lawn and other plantings can grow rapidly, a petrol cutter is used to tidy up the local area and mow the lawns, which is also called a brushcutter or trimmer, a petrol mower.

Traditional braids are inconvenient and unsafe to use, require a significant investment of time and effort, which will help save gas mowers, combining functionality and practicality in their design. In the photo of the petrol brush, you can see various high-tech devices, which are inherent in a set of operational characteristics, including such parameters as increased productivity and a long service life.

A convenient and reliable trimmer is a technical device consisting of individual mechanisms, parts and elements that can wear out, become unusable and damaged during intensive use.

Even with regular technical inspection, maintenance procedures and careful storage, such devices and their individual parts require repair and even replacement, all repair procedures can be performed independently.

Brief content of the article:

The easiest way is to give the petrol cutter for repairs, having allocated a certain amount of funds from the family budget, prompt and high-quality repair with your own hands is no less simple and convenient if you want to understand the design of the petrol cutter and fix all the problems.

Image - DIY gasoline trimmer carburetor repair

The mass and piece production of trimmers is based on the use of generally accepted technology, a typical design scheme consists of certain elements and parts, it is important to know them when carrying out independent repair work:

top part. The basis of the entire structure, where all important elements are collected, such as a starter, a carburetor and a petrol cutter engine;
middle part. A hollow rod, inside it is a cable that connects the motor and the gearbox, which drives the cutting line. In this part there are fasteners for distributing the weight of the entire structure and a belt for fixing the trimmer on the belt of a person using the trimmer for its intended purpose;
Bottom part. It houses the gearbox and cutting elements, which are hidden under a practical cover to protect the user. The casing provides an increased level of safety, preventing large fractions of debris, stones and glass from entering a person while working with a petrol cutter.

Knowing exactly the internal structure and the principle of operation of the trimmer, you can independently carry out repair measures for the structure or replace individual components that have become unusable, using the repair instructions.

The most common and common failures of the unit that need to be corrected on their own include the following problems:

engine malfunction, due to which the brushcutter does not start and does not work;
increased vibration of the brushcutter bar, which complicates its intended use;
increased overheating of the gearbox, its accelerated heating during operation;
slow and weak functioning of the cutting line at insufficient speed;
clogging of the starter grille, causing overheating of the engine and its refusal to work;
fast and frequent clogging of the carburetor due to the use of low-quality fuel;
clogging of the air filter due to non-observance of the measures for the care of the device.

All these problems can lead to the fact that the device will lose its working capacity. Before ordering the necessary spare parts for the mowing, a visual inspection and diagnostics of the device should be carried out.

Particular attention should be paid to individual spare parts and units of the device, to check them you do not have to contact a professional master, a set of diagnostic measures will help you to identify the consequence of a loss of performance with your own hands.

If the trimmer motor does not start or stalls immediately after starting, when the gearbox overheats or during the operation of the device, extraneous noises are heard and vibration is clearly felt, it is important to visually inspect and identify a non-working unit.

To optimize the preparatory measures before repairs, you should carry out a simple diagnosis and check step by step:

the presence of fuel in the tank and lubrication in the main units;
serviceability of the spark plug and its performance;
the cleanliness of the fuel and air filter of the brushcutter;
clogging of the outlet channel and breather of the device;
the quality of the fuels and lubricants used.

To determine the functional efficiency of the petrol-cutter's ignition, it is necessary to determine whether the spark plug is working by testing the appearance of a spark when it comes into contact with the body of the functional device.

The spark plug itself can be replaced with a new one, having previously dried the candle channel, if necessary, the old element is also dried, cleaned with special devices and returned to its place.

In the process of inspecting the carburetor, it is worth paying attention to the possible leakage of the fuel used; to identify problems with the carburetor, the following measures must be taken:

purging the fuel hose to eliminate possible blockage of the element;
checking and replacing the gasket between the engine and the carburetor;
determination of tightness and maintenance of constant pressure in the unit.

If necessary, you can personally disassemble and thoroughly clean the unit using gasoline, the jet and channels are cleaned using compressed air.

The gearbox transmits torque from the motor shaft to the cutting tool, its gears during operation must be absolutely clean and always lubricated with special grease.

Carrying out a technical inspection on your own once a season will allow you to get rid of the need to repair the gearbox or replace it, with the purchase of an expensive new unit.

The starter is necessary to bring the trimmer into working condition, its diagnostics consists in checking the tension of the starter cord connected to the teeth of the starter coil, which are often destroyed during an abrupt start.

An inoperative starter in a petrol cutter cannot be repaired; it must be replaced with a working unit as part of a mandatory technical inspection or a set of repair measures.

Cutting elements require special attention and care, which must always be cleaned of dirt and cut grass after use. Regular inspection and thorough preparation of the device for operation will help to avoid costly and time-consuming repairs, and always be confident in the performance of the petrol brush.

Carburetor repair of mowers Very often complaints of owners of gasoline trimmers are associated with various kinds of defects in the carburetor. Naturally, it is most ideal in this case to seek help from a specialist.

Very often, complaints from owners of gasoline trimmers are associated with various kinds of carburetor defects.

Naturally, it is most ideal in this case to seek help from specialists in this field, for whom the repair of carburetors of gasoline trimmers is an integral part of the profession.

Do not try to repair the device without the help of others, since repairing the carburetor of the mowers with your own hands can lead to even greater damage and even huge costs for fixing it.

But if you are still familiar with the basic mechanisms of the trimmer carburetor, you can try to figure out the dilemma yourself, so as not to overpay in the service, because from time to time the breakdown can be really frivolous.

This article is just created in order to help you cope with the malfunction.

Further, more often encountered breakdowns and the prerequisites for their occurrence will be sorted out.

First, you should generally look at the carburetor and find out if there is any fuel leakage.

If it turns out that there are no problems with fuel, you need to remove the carburetor from the engine and check the condition of the gasket located next to the carburetor.

If no defects are observed here, you can test to check the carburetor for the degree of density.

To do this, you can purchase a special device, which is part of the tool kits for repairing the carburetor of brushcutters and which is a special pressure gauge that, in fact, inspects the density.

Curious! The benzokos stalls, here!

If you do not want to spend money on its purchase, you can use an ordinary honey tonometer, on which you just need to change the pressure gauge.

When using this device, pay attention to the indication.

If the pressure does not drop and remains similar over time, you can be measured, as this indicates the density of the carburetor.

If the pressure begins to decrease after a certain time, it means that there are still difficulties.

They can be associated with damage to some parts of the carburetor.

In this case, the only way out is to replace the faulty parts with new ones. In addition, clogging of channels or jets can become a prerequisite for malfunctioning of the carburetor.

Even ordinary drops of water can play a negative role here, which can clog the openings of the jets or channels.

If you find a lack of density in the carburetor, wash it outside with gasoline and disassemble.

Remember that in order to repair the carburetor of the brushcutter yourself, channels or nozzles, you cannot use needles or iron wire, as they can change the flow sections.

These are the main faults in the carburetor that you can easily fix without the help of others.

If you did not find any of the listed problems in your own carburetor, it is recommended to contact a special service for help.

Petrolcutters, like all petrol 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, adjusting the carburetor of a petrol cutter with your own hands is a matter of 5 minutes.

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

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

Mesh filter. With this element, most often there are only two difficulties:

In order to find out the cause of the breakdown, the fuel filter cap is unscrewed to remove the strainer. If dirt has simply accumulated on it, then flushing in gasoline or blowing will help.

If there is visible damage to the mesh filter, it is imperative to install a new one. There may also be damage to the fuel supply pipe (during repairs, they practice checking this element).

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

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

The body of the throttle valves, the places of the bundles of the carburetor parts, the inlet or outlet pipeline - all of these parts are susceptible to depressurization. You can probably check with a simple method - smear the problem area with soapy foam.

The base of the carburetor of the petrol cutters is a duralumin body. It houses a diffuser (hole with inner contours). Air is blown through this hole. The flow rate of oxygen (air) depends on the cross-section (orifice) of the diffuser.

The diffuser is equipped with fuel channels. From them, fuel is drawn in with the help of a stream of air.

Outside the carburetor is installed:

fuel pump;
jet system;
a system for adjusting the consistency of fuel with air;

The throttle valve determines the amount of air to be supplied, and the power of the motor directly depends on this.

Fuel is sucked into the carburetor system by a pump (its membrane). Then it goes through the choke in the carburetor. Then the liquid moves through the inlet and outlet valves of the pump. Filtered by the grid. It moves through the needle valve into the diaphragm chamber.

Phased operation of the device:

Air supply to a tube with an air baffle (damper). The baffle regulates the intensity of the air flow.
The fuel supply system is necessarily narrowed by the mixer to accelerate the flow.
Gasoline through the float chamber and the nozzle tube with a constriction. A float chamber adjusts the temporary volume of gasoline. In the float chamber, the pressure level is neutral, and in the tube with a constriction it is already small. Due to the pressure drop, the fuel seeps through the jet.
The acceleration of the air flow facilitates the transfer of fuel (gasoline) and its atomization. Ultimately, an air-fuel mixture of the desired proportion or density appears.
The air / fuel mixture seeps into the engine cylinder through the fuel pipe.

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

Simply put, adjusting the carburetor on a petrol cutter is the creation of a good fuel consistency due to the correct air supply.

Before adjusting, you need to painstakingly clean the filters according to the maintenance in the annotation.

The upcoming do-it-yourself adjustment of the carburetor of the petrol cutter is done with the adjusting screws. There are three of them:

Right (L) - Fuel Consistency Adjustment for Low RPM.

It is necessary to find the highest idle speed. To do this, slowly unscrew the screw (L) to the right and to the left.

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

Lower (T) - is responsible for adjusting the motor at idle speed.

clockwise - increase;
counterclockwise - decrease.

For the correct adjustment of the idle speed, it is typical:

stable operation of a cool motor;
not overestimated speed of a hot engine;
a large supply of turns for the trimmer head;
stable operation of the motor when changing position (sharp rise or lowering of the knife).

Left (H) - consistency adjustment at high speeds. (The screw is adjusted last).

The general adjustment of the highest speed, engine power, temperature and gasoline consumption depends on the left screw (H).

Setting up the carburetor of a petrol cutter with the last screw is done as follows:

Spare parts for Chinese brushcutters Chinese brushcutter repair

If you have problems with the operation of a Chinese brushcutter (trimmer), it does not start or does not work well, then in large.

Open the throttle to full, while at the same time give full throttle. Turn the screw clockwise until the revolutions drop (in this case, orientate by ear).

Turn the screw counterclockwise as slowly as possible until the engine runs unevenly.

Then turn back quite a bit, barely hearing a stable, even operation.

For a more visual use 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 video, the setting (its correctness) is determined by the color of the candle, and not only by the speed and stability of the engine. Image - DIY gasoline trimmer carburetor repair

Correct carburetor setting do it yourself in this case - combustion of the fuel mixture without residue, the color of the candle should be light brown.

The benzokos is one of the main tools of the summer resident, used to quickly put the land in order. Owners of private houses also purchase this tool for mowing grass in the backyard. The period of active use of petrol cutters and electric trimmers is in the summer. Before starting operation, the tool is brought into working condition: rubbing parts are lubricated, the cutting attachment is changed, a fuel mixture is poured into the tank. If the engine does not start at all or stalls quickly, without gaining a sufficient number of revolutions, then you have to look for the causes of the malfunctions and eliminate the identified malfunctions. To carry out repairs petrol cutters with their hands, you need to understand its structure and the principle of operation of the main units. This information can be found in the instructions for use, which the manufacturer applies to the garden equipment without fail. Check for such a guide when purchasing your chainsaw. The imported tool must be accompanied by instructions written in Russian.

A long tubular rod is attached to the gearbox of a two-stroke internal combustion engine. A shaft passes inside the rod, which transfers torque from the gasoline engine to the cutting mechanism. The line or knives rotate at 10,000 to 13,000 rpm. There are holes in the protective housing of the gearbox, into which grease is injected with a syringe. For the convenience of using the tool, the manufacturer equips it with a special adjustable shoulder strap.

A cutting attachment is attached to the brushcutters:

The line, which varies in thickness from 1.6 to 3 mm, is located in the trimmer head. The line is subject to wear during mowing. Changing the line is quick and easy in two ways: by winding a line of the same diameter onto a bobbin or by installing a new spool with line already wound.
Steel knives with double-sided sharpening for the benzokos for clearing the area from weeds, small bushes, hard grass. Knives differ in shape and the number of cutting surfaces.

On the U-shaped, D-shaped or T-shaped handle, which is attached to the boom, there are the petrol cutter control levers. The cutting mechanism is protected by a special casing. Household brushcutters are filled with a mixture prepared from gasoline and oil, which is poured into the fuel tank. The device of semi-professional and domestic brushcutters, equipped with a four-time gasoline engine, is slightly different. The filling scheme is also different: oil is poured into the crankcase, and gasoline is poured into the tank.

The measured piece of fishing line is folded so that one end is 15 cm longer than the second.We put the loop into the slot on the spool and start winding in the direction indicated by the arrow

If you cannot start the petrol cutter, then the first step is to check the presence of fuel in the tank and its quality. For refueling the tool, it is recommended to use high-quality gasoline purchased at gas stations, the grade of which should not be lower than AI-92. Saving on cheap fuel can lead to a breakdown of the cylinder-piston group, the repair of which can take a third of the cost of the brushcutter itself. It is equally important and correct to prepare the fuel mixture from gasoline and oil. The proportional ratio of these components of the mixture is indicated by the manufacturer in the manual. It is not necessary to prepare the fuel mixture in large volumes, since its properties are lost during long-term storage. Better to use a freshly prepared mixture.

On trimmers, in addition to electric motors, gasoline internal combustion engines are installed. This mechanism requires special attention to itself, because if it is incorrectly configured, it will either refuse to work, or it will work intermittently and loss of power.Basically, engine tuning is about adjusting the fuel supply, and this is done with the help of the carburetor trimmer.

It is almost impossible to cover all types of carburetors produced by manufacturers of gas trimmers. But, since the design of this module, as well as its principle of operation, is largely similar between different models, a generalized description of the processes occurring in the carburetor can be made. This information will allow the user to understand the principles of operation of the device, to eliminate the malfunctions that have arisen and to operate it correctly.

The carburetor trimmer is based on one-piece aluminum body... Below is a diagram of this block.

At the bottom of it, there is a diffuser, which is also called Venturi nozzle (eighteen). Air is drawn in by the motor through this nozzle.

The smaller this hole, the faster the air flows, and the higher the level of its vacuum in the zone with the smallest diameter.

At the top of the diffuser are fuel channels (11.12). Through these channels, the air flow draws in gasoline. The fuel pump itself, jets and the system used to regulate the supply of the fuel-air mixture can be built-in or installed externally.

Throttle valve (9) adjusts the amount of air sucked into the carburetor. Its amount affects the power that the engine develops. The damper (7) is used for cold starting. It must be closed if you are going to start the unit. After the engine has started, it must be opened, otherwise, the engine will immediately stall.

Impulse channel (1) connects the impulse chamber of the pump to the crankcase of the engine, namely, to its internal volume. The piston located in the cylinder, making reciprocating movements, successively changes the pressure in the crankcase (vacuum or pressure increase). The pressure drops force the diaphragm (4) to move. Therefore, the operation of the pump is synchronized with the operation of the engine.

The suction of gasoline from the tank occurs precisely with the participation membranes (4). Gasoline enters the carburetor through the union (2). Further, its path lies through the inlet valve (3), the outlet valve (5), through the mesh filter (6), the fuel channel (10), passes the needle (14) and fills the chamber (16), which has a control diaphragm (18) ...

The valve (14) is connected to the diaphragm (18) by means of a lever (17). The cavity, which is located below the membrane, is connected to atmospheric air through the hole (19).

The device operates as follows.

A vacuum is generated in the diffuser during the suction stroke. This fact causes air leaks. The position of the throttle valve (9) determines the amount of air entering the carburetor chamber, as well as the engine power and the number of revolutions.
At this time, fuel is sucked in from the chamber (16) through the jets (11,12), after which it is mixed with the flowing air. Gasoline, mixing with air, begins to spray. Thus, a air-fuel mixture.
The finished mixture enters the cylinder, where it is compressed by the rising piston and ignited at its highest point from the spark generated by the spark plugs.
Since the volume under the control diaphragm (18) is connected to atmospheric air through the channel (19), the diaphragm goes up, opening the valve (14) by means of the lever (17). After opening the valve (14), a new portion of fuel enters the chamber (16).
After the chamber (16) is full, the diaphragm (18) returns to its original position and the valve (14) closes.

Further, when the motor is running, all the above processes are repeated. A screw (13) is used to adjust the amount of fuel entering the diffuser through the nozzles. The screw (15) is also used to adjust the idle speed. When the regulators are twisted, the fuel mixture is enriched, and when the regulators are twisted, the mixture becomes lean.Also, in some models of carburetors, you can adjust the idle speed of the engine. quantity regulator... It is usually located outside and, when twisted, abuts against a lever attached to the throttle shaft.

Thus, using 3 adjusting screws, you can achieve maximum engine performance, as well as adjust its smooth operation at any ambient temperature, and even in mountainous areas.

Failure of the trimmer carburetor occurs due to the use of poor quality gasoline, a damaged air filter and the accumulation of dirt in the chamber of this unit. Most often, it is quite possible to repair the carburetor with your own hands. Listed below are typical brushcutter carburetor malfunctions.

A common malfunction that "haunts" the fuel pump is deformation of the pump diaphragm... For this reason, it does not fit properly and the pumping passages are not sealed.

The reasons for membrane deformation can be the following:

long work of the trimmer;
use of unsuitable fuel;
ingress of gases into the impulse channel.

As a result, diaphragm damage reduces pump performance and, as a result:

depletion of the combustible mixture occurs;
it is difficult to start the engine;
there are interruptions in the operation of the motor;
the piston is damaged.

Also, the above-described consequences for the engine can cause clogging of the pump cavity with impulse side... In this case, dirt enters the membrane through the impulse channel.

To clear the blockage, you will have to disassemble the carburetor and clean the membrane.

The strainer can become dirty if contaminated fuel enters through a fuel hose or a defective pickup head. In the photo below you can see what a clean filter looks like and a dirty one (parts are separated by a line).

Troubleshooting will require a thorough cleaning and rinsing of the strainer. Also recommended blow with compressed air all holes in the carburetor trimmer housing.

This failure occurs when the contact surface of the lever wears out.

The abrasion of the contact surface occurs due to the presence in gasoline abrasive particles or due to strong vibration of the motor during operation. This defect in the control lever causes problems with the intake, as well as improper idling of the engine.

The inlet needle breaks down, as a rule, due to the presence of abrasive particles in the fuel fluid.

the tightness of the inlet needle seat is disturbed;
there is a leakage of a combustible mixture;
there are malfunctions in the engine operation associated with re-enrichment of the fuel mixture.

Also, the inlet needle may just jam.

A jammed inlet needle can cause the presence of dirt in the fuel, or a long idle device without work.

If dirt accumulates in the control cavity, the inlet needle cannot close the hole tightly and a lot of fuel pours into the chamber.

It causes re-enrichment of fueland the engine starts to malfunction. It is necessary to disassemble the carburetor and clean the cavity of the control membrane.

The membrane can undergo deformation during prolonged operation of the unit and when using aggressive fuels.

Failure of normal adjustment due to a defect leads to:

damage to the piston;
difficulties when starting up;
depletion of fuel;
improper engine operation.

This problem can occur if the adjusting arm is not properly installed or if it bends before installing. As a result, the contact surface is in the wrong position, which disrupts the additional fuel supply.

The throttle and choke valves are mainly subject to wear due to the presence of abrasive particles in the air. Defective flaps look like they have been sandblasted.

As a result of valve wear, engine performance decreases, malfunctions appear in its operation, piston rings, piston and cylinder coating wear out.

The air and throttle shaft can wear out for the following reasons:

insufficient and improper maintenance of the air filter;
the air filter is damaged;
the air filter is not suitable for this unit.

Due to hit poor quality purified air, the shaft will wear out and may break. Broken shaft parts can enter the combustion chamber or crankcase and cause serious damage to the entire piston system.

To eliminate problems with air purification, it is necessary to replace the defective filter or flush the existing (serviceable) one. The filter must be washed in soapy water and dried.

Carburetor adjustment is necessary in the following cases:

the new engine was run-in (4-5 liters of fuel mixture were used);
the composition of the fuel has changed (brand of oil and gasoline);
the weather has changed (it became hot, cold);
the rarefaction of air has changed (applies to mountainous regions);
after long-term storage;
increased load on the engine (after changing tools, etc.);
due to vibration, the adjustment screws spontaneously unscrewed;
fuel consumption has increased, the carburetor overflows fuel;
carbon deposits quickly appear on the spark plug electrodes (while the fuel mixture is prepared correctly);
the engine starts and immediately stalls or gains momentum poorly;
gasoline does not enter the cylinder;
a large amount of exhaust gases.

Before you start adjusting the carburetor trimmer, you must do the following:

flush the engine;
replace or clean the spark plug;
change to a new one or clean the air filter (it is recommended to wash it in warm, soapy water, wring it out and let it dry well).

It is also necessary set cord a suitable diameter in the trimmer coil or install knives - this is done so that during the tuning process the engine has at least some kind of load. After installing the cutting tool and starting the gasoline engine, let it warm up for 10 minutes.

If at idle motor, you notice that the cutting tool is rotating, so it is necessary to reduce the engine speed. This is done using the lower idle speed control, often marked with the letter “T”. The illustration below shows the placement of the adjusters on a Husqvarna trimmer.

But, for example, on a Stihl trimmer, this screw may be marked “LA”.

So, turn the idle speed control to the left until the trimmer head comes to a complete stop.

To adjust the carburetor, 3 regulators (screws) are used.

Right adjuster L adjusts the level of enrichment of the combustible mixture at low speeds. It needs to be regulated first. Achieve maximum idle speed. This is done with the L knob by turning it left and right. After finding the point of maximum speed, return the regulator half a turn to the left (counter-clockwise).
Lower T adjuster (LA) used to adjust idle speed. Turning it to the left, the engine speed will begin to decrease, and turning the regulator to the right, the engine speed will increase.
Left Knob H is responsible for enriching the combustible mixture at high speeds. The enrichment setting completes the carburetor setting. Also, using this regulator, you can adjust the maximum speed, fuel consumption and engine power.

Important! If the engine is allowed to run at full speed for more than 10 seconds, it may fail.

To eliminate this nuisance, adjustment will be required. With the engine running, give full throttle, then turn the “H” regulator to the right until the speed starts to decrease. After that, the “H” regulator must be slowly scrolled to the left until you hear the uneven operation of the engine.Then you should turn the knob “H” to the right until you hear the smooth operation of the motor.

After carrying out the above steps, the carburetor setting can be considered complete. After correct adjustment, the engine should confidently pick up speed, a little quarter at maximum speed, and when idling, the cutting tool should not turn. This manual is suitable for adjusting carburettors on Huter, Patriot and other brushcutters.

There are also carburettors without screw, responsible for the enrichment of the combustible mixture at low speeds. That is, they have only 2 adjusting screws: an idle speed regulator and a fuel mixture quality regulator at high speeds. How to tune this type of carburetor can be found in this video.

Video (click to play).