How to adjust the gas on a walk-behind tractor

How it works?

If we consider the carburetor from a constructive point of view, then it is arranged quite simply.

It contains the following nodes:

  • throttle valve;
  • float;
  • the valve, the role of which is to lock the chamber, it is installed of the needle type;
  • diffuser;
  • fuel atomization mechanism;
  • a chamber for mixing gasoline and air;
  • fuel and air valves.

In the chamber, the role of the regulator responsible for the amount of incoming fuel is played by the float. When the level reaches the minimum allowable, the needle valve opens, the fuel in the required amount again penetrates inside.

There is a spray gun between the mixing chamber and the float chamber. The fuel subsequently turns into a single mixture with air. The air flow is transferred inward through the nozzle.

The operation of the walk-behind tractor is provided by the engine, inside of which no ignition can occur without the required amount of oxygen, which is why it is required to properly adjust the operation of the carburetor.

In the design of such equipment, units of two types are used:

  • rotary;
  • plunger.

Each of them has its own advantages and disadvantages, the use of one or another carburetor is due to the type of work performed and other characteristics of the equipment.

Rotary carburetors are most often used in motoblock designs. They are designed for 12-15 cubic meters. m. This design has gained popularity due to its simplicity.

For the first time, carburetors of this type were used in aircraft construction and the automotive industry. Over time, the design has undergone some changes and became more perfect.

In the center of such a carburetor, a cylinder is installed in which there is a transverse hole. When rotating, this hole opens and closes, thus, the air flow passes through the unit.

The cylinder not only makes a rotational action, but also gradually approaches one side, it is similar to unscrewing a screw. When operating at low speed, this carburetor is less sensitive, the hole opens only slightly, turbulence is created, as a result of which the fuel does not flow in the required amount.

Even if you run it to the maximum, there are many elements in the design of such a unit that will hinder the development of high power, since the air flow remains strictly limited.

In walk-behind tractors, this is used as an advantage, since instant acceleration is not required when the engine is running. Plunger carburetors have many of the same elements that are installed on the rotary model. The only difference is that they cost differently here, hence the ability to increase engine power faster.

There is no hole in the central section, so the cylinder is almost solid. To allow air to pass through, the cylinder moves, and at low speed, it moves into the carburetor, thus, most of the air flow is blocked, thereby reducing the number of revolutions.

When the user presses on the gas, the cylinder moves, space opens, and air freely enters the chamber where the fuel is located.

All about carburetors of motoblocks

  • How it works?
  • Views
  • Adjustment
  • Repair and maintenance

Without the carburetor inside the construction of the walk-behind tractor, there would be no normal control over hot and cold air, the fuel would not ignite, and the equipment would not work efficiently.

For this element to work properly, it needs to be carefully monitored and tweaked.


Each user was faced with the problem of unstable operation of the carburetor, since over time, any technique can fail. This is one of the first reasons why it becomes necessary to independently adjust the operation of the unit.

Experts advise to follow the sequence of actions if the setting is done independently:

  • at the first stage, the user is required to turn the throttle screws to the end, and then half a turn;
  • activate the ignition and let the engine warm up a little;
  • without muffling the unit, set the speed lever to the minimum permissible mode;
  • start idling to the maximum possible;
  • again turn on idling to a minimum;

Setting up and Starting the BCS 749 Power Safe!!

  • these last few steps will need to be repeated several times until the motor begins to demonstrate stable operation;
  • at the end, the control lever is set to gas.

Repair and maintenance

Sometimes it is not enough to adjust the operation of the carburetor and one of its parts needs to be replaced.

The most common cause of the problem is the air damper, which stops closing completely. In this case, you will first need to check how the drive works.

If jams are found, they must be eliminated.

Serious breakdowns can be avoided only if you constantly monitor and control the operation of the unit. In addition to adjustment, cleaning is necessary or simply replace worn parts.

The reason for the pollution can be hidden in poor quality fuel or dirty air. Filters, additionally installed in the carburetor design, make it possible to correct the situation.

It is necessary to select high-quality fuel, because it significantly affects the resource of use of all elements in the unit design. You can learn how to disassemble the carburetor yourself or hand it over to specialists. The first way is chosen by those who want to save money. During the operation of the walk-behind tractor, dust and combustion products collect inside its device, then the efficiency of the element decreases.

In this case, cleaning can help, which is performed in the following sequence.

  • Remove the carburetor from the walk-behind tractor.
  • Drain the fuel completely.
  • An inspection of the nozzle is carried out, in the case when the fuel is removed from it poorly, then it must be purged. A compressed air cylinder is used. After that, it is turned 180 degrees, if the fuel no longer flows, then it works normally.
  • The next step is to check the jets. To do this, you need to remove the screws that are responsible for the gas and remove the carburetor body. The jets are flushed together with the fuel cock. The best remedy in this case is gasoline, then blown with air.
  • Next, you need to decompose the washed elements, and then assemble the carburetor in the same sequence.

When assembling, it is important to pay attention to the location of the spray tube, which should be opposite the hole present at the top. Only after that, the carburetor is again installed on the walk-behind tractor.

All described methods are suitable for motor-blocks “K-496”, “KMB-5”, “K-45”, “DM-1”, “UMP-341”, “Neva”, “Pchelka”, “Cascade”, Mikuni, Oleo-Mac, “Veterok-8” and others.

Cleaning a Japanese carburetor and adjusting it is as easy as any other manufacturer’s unit. There is no difference, since the design is almost the same for everyone, the main thing is to know the technology.

You will learn how to disassemble and clean the carburetor of an air-cooled walk-behind tractor from the video below.

How is the carburetor adjustment of the walk-behind tractor

What to look for during a motor failure? If a carburetor malfunction occurs, the first step is to check the fullness of the fuel tank and the oil level. If there is enough fuel and oil, then proceed to inspect the spark plug. To do this, unscrew it and check the spark with the ignition. Next, the flow of gasoline to the carburetor is tested. For this purpose, remove the hose from the fitting and monitor the flow of fuel. If no fuel appears, then most likely the filter mesh will need to be cleaned. For this, the fuel cock is unscrewed and all parts are rinsed with gasoline. The same is done with the carburetor jet.

Carburetor cleaning is done as follows. To clean the device, you must first remove it. To easily remove the carburetor, you need to carefully inspect the body of the device and unscrew all the parts on which it rests.

So, remove the carburetor and pour gasoline out of it. We carefully separate all parts of the device (jet, float) for further purging and cleaning. This manipulation is performed with a special cleaner.

If it is heavily soiled, you can use a compressor.

After cleaning, we thoroughly dry all the parts and feel free to start assembling. After assembly, adjust the carburetor for the walk-behind tractor.

We install the cleaned device using a standard gasket and fasten it with nuts. Don’t forget about the air filter, speed regulator and gasoline hose.

Setting up the carburetor of the walk-behind tractor is to adjust it. In order to independently adjust the carburetor, you need to do the following steps:

  • Screws at low and full throttle must be tightened all the way.
  • Unscrew the low and full throttle screws one and a half turns (set the throttle valve in such a position that a gap of the appropriate size is formed between the base and the air duct).
  • Start the engine and wait until it warms up.
  • With the engine running, set the control lever to minimum speed.
  • Achieve smooth engine operation. To do this, you need to make the minimum idle speed using the throttle screw.
  • Set idle speed to maximum with idle screw.
  • Set idle speed to minimum with throttle screw.
  • Repeat steps 6 and 7 until the engine starts to run continuously.
  • Set the engine control lever to gas.
  • If an interruption occurs, unscrew the screw that regulates the quality of the mixture, no more than 2.5 turns.

I would like to note that the adjustment of the carburetor on the Neva walk-behind tractor is done clearly according to the above instructions. The K-45 device installed on the Neva walk-behind tractor is single-chamber and horizontal. The float chamber is located in the central part. Throttle body. flat.

The Neva walk-behind tractor uses the DM-1K engine, which is produced at the Krasny Oktyabr Neva plant. The manufacturer categorically does not use Chinese-made engines. This also applies to the production of a motor-cultivator.

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Repair of K-45: basic recommendations, video

In order to fix the carburetor with your own hands, we suggest that you familiarize yourself with the video of the repair of the “Neva” MB-2 walk-behind tractor.

Consider the main malfunctions of the K-45:

  • If an excessive amount of air enters the internal combustion engine chamber. Try replacing the gasket between the head and carburetor and tightening the fastening nuts on the joint tighter. If this does not help, the cause may be wear on the shaft on the damper or the hole where it is connected. Such a shaft must be replaced, and in the case of broken holes, the entire device is replaced.
  • When too much fuel enters the float chamber. In this case, check and replace worn parts: float, jets, needle.
  • If the carburetor is running low on gas, check the filter and sump, fuel hoses, and gas tank. Contaminated elements must be rinsed or replaced, and if the inside of the tank is rusted, you will have to clean it with caustic soda.
  • If there is an increase in fuel consumption, adjust the carburetor by referring to the operating instructions.

The device and adjustment of the carburetor K-45

Motoblock Neva of the MB-1 and MB-2 models is equipped with a DM-1K engine with a K-45 carburetor. There are also modifications of the model, such as K-45R, K-45U, K-45M.

For the correct configuration, we will briefly consider its device.

Carburetor. an engine unit that pours fuel, mixing it with air, and regulates its flow into the cylinders.

BCS tractor Clutch adjustment

Consider the K-45 scheme. Here, the throttle lever 11 is located at the bottom of the damper, which regulates the amount of the mixture of gasoline and air. The regulator rod is attached to it. In the upper part of the throttle valve there is a stop screw 5. The main throttle lever 14 controls its position. In the closed position, it is held by a spring, and when the internal combustion engine is started, it opens to a certain angle. The degree of the angle is calculated so that there is no excessive enrichment in the fuel mixture of the cold engine of the walk-behind tractor.

Adjustment of the K-45 allows the entire power system and the engine itself to work without interruptions:

  • prepare the carburetor for tuning and warm up the motor-block motor;
  • reduce the speed of rotation of the engine with screw 5;
  • using screw 8 it is necessary to set the maximum idle speed of the engine;
  • and finally change the rotation speed by turning the screw in the opposite direction 0.25 turns.

Features of adjustment for different brands

As noted earlier, the carburetor of the walk-behind tractor is configured in the same way, regardless of the brand: Neva, Cascade, Agros (or Argo, as it has been called since 2012), Lifan and others.

If, after carrying out all the manipulations described above, the carburetor continues to work incorrectly, it will need to be removed and inspected. The assembly may need repair, cleaning or flushing of parts.

After adjustment, be sure to check the spark plugs for contamination: clean them from carbon deposits or replace them if they are faulty, adjust SZ.

Carburetor operating instructions

Gasoline supplied to this device must not contain mechanical impurities.
All parts are processed exclusively with gasoline. Do not use a solvent, as the elasticity of the washer and rubber parts is damaged.

Use compressed air to dry the parts. Cleaning small holes with a wire or needle is not recommended. Installation after repair or cleaning must be carried out evenly so that there are no bends and deformation of parts.

The float chamber must be tightly connected to the body. Check the air filter connection before use. There should be no gasoline leaks.

Prepare the carburetor before starting the engine. To do this, you need to make sure that no gasoline leaks from it. To do this, simply open the fuel cock. Close the air damper and turn the control lever until it stops. Open the throttle valve 1/8. 1/4 of the maximum stroke.

At low air temperature (below 5 ° C), squeeze the drowner until fuel appears from the hole.

During starting, slightly open the choke, and after warming up the engine, open it completely.

Replacing with another carburetor

In order for the carburetor of the walk-behind tractor to work properly and without interruptions, it is necessary to constantly monitor the condition of the filters, adjust for the correct supply of fuel and air, and also use gasoline with an octane rating of at least 92. In case the breakdown of the K-45 could not be avoided :

  • purchase an original node;
  • dismantle the faulty mechanism, starting from the engine head;
  • drain the remaining fuel from the faulty carburetor;
  • clean the connection and replace the assembly.

Or contact the service for a replacement. If you want to put a different brand of carburetor on the unit, buy the necessary adapter.

How to adjust the carburetor of a walk-behind tractor with your own hands: device diagram, K-45, video

Adjustment of the carburetor of the walk-behind tractor should be carried out periodically in order for the mechanism to work properly. A possible cause of differences in the operation of the engine of the walk-behind tractor can be the carburetor. For this, the device is disassembled, cleaned and adjusted (tuned). Regardless of the brand of carburetor and the device on which it is installed, the principle of regulation is the same for everyone. The difference can only be in the number of revolutions.

Carburetor for walk-behind tractor: adjustment, repair, maintenance

The carburetor is the element of the walk-behind tractor that is necessary to control the flow of air and fuel.

Thus, the optimization of the motor operation is carried out at a stable load. Like any mechanism, the carburetor needs proper care.

Types and methods of carburetor adjustment

As you know, the walk-behind tractor, like many other units of this type, works with the help of an engine. Due to the fact that the engine cannot ignite without supplying oxygen, it becomes necessary to use a carburetor. Two types of carburetors are used for the walk-behind tractor. One of them is rotary, the other is plunger. Naturally, each of the mentioned types has its own advantages and disadvantages, the choice depends on the walk-behind tractor, its performance and the type of work performed.

There are times when there are abnormalities in the operation of the carburetor (the process is unstable). In such a situation, the carburetor needs adjustment. How to adjust the carburetor on the walk-behind tractor? It is quite possible to do it yourself, following a certain sequence of actions.

  • First, you need to turn the screws (full and low throttle) until they stop. Then turn them one and a half turn.
  • Turn on the engine, give it time to start and warm up.
  • Do not shut off the engine and place the motor control lever in the lowest speed mode.
  • Next, set the minimum number of revolutions when the device is running stably.
  • Then run idle to maximum.
  • Shift idle to minimum. Repeat this action, alternating with the previous one, until the engine starts to run smoothly.
  • Move the control lever to the “throttle” position.

Following such instructions, you can independently adjust the carburetor of the walk-behind tractor.

Carburetor care, replacement and repair

Sometimes, in order to bring the carburetor for the walk-behind tractor to a stable, working condition, there is not enough adjustment, repair or replacement is needed.

It so happens that the carburetor choke does not close completely. To eliminate this problem, you should check the operation of the drive. If jamming is found, remove it. over, given that the carburetor provides fuel and, therefore, drives the walk-behind tractor itself, you should carefully monitor the condition of this part and take proper care of it.

To avoid serious damage to the carburetor, you must constantly monitor its operation. In addition to adjusting the idle speed, you need to regularly clean the carburetor and replace worn parts. Since the carburetor interacts with the fuel mixture and air, the cause of its contamination can be either in the first or in the second source.


Minsk Tractor Works produces several models for work in difficult conditions. However, all of them are based on the experience of production and operation of the very first design, accepted for manufacture in 1978. “MTZ-05”. The line of heavy equipment is represented by a lineup based on MTZ-09. Remote control adjustment:

  • Warm up the engine to operating temperature.
  • Screw in the low and maximum throttle screws completely. Then weaken them by 1.5-2 turns, rotating in the opposite direction.
  • Transfer the accelerator lever to XX mode.
  • Regulate the idle speed of the engine with the idle screw.
  • The maximum crankshaft speed is set by the maximum power regulator.
  • After obtaining a satisfactory result, tighten all screws.

Setting up the power system

A carburetor for a walk-behind tractor is a mechanism, the performance of equipment depends on the accuracy of its adjustment. “Floating” rpm, torque dips, starting difficulties are signs that the remote control needs to be adjusted. If the device has low idle speed, and it periodically stalls, it is necessary to slightly increase the crankshaft speed. To do this, turn the adjusting screw clockwise under the throttle actuator. If it is necessary to reduce the speed, the regulator, on the contrary, is unscrewed.

The carburetor is one of the most important units of the petrol cutter, the function of which is to prepare fuel.

fine tuning of the remote control implies its complete disassembly and the establishment of the required level of flammable liquid in the float chamber. At the same time, the revision of the moving mechanisms is carried out, the internal surfaces are cleaned from oily deposits. The gasoline level is controlled by the position of the float in the primary chamber. If during operation there is dark smoke from the exhaust pipe, and there are traces of unburned fuel on the spark plugs, these are signs that the fluid level is too high. By bending the spring mechanism of the needle valve, set the correct position of the float.

Cleaning the carburetor

To adjust the level, the carburetor on the walk-behind tractor is completely cleaned of dirt beforehand. Before starting work, drain the fuel from the gas tank. To do this, unscrew the drain plug or remove the supply hose. The gasoline is poured into a clean canister or plastic container. Before refilling, it is advisable to pass the flammable liquid through a filter. After emptying the fuel tank, dismantle the supply hose, dry it and blow it off with compressed air.

The remote control is attached directly to the cylinder head. To remove the dosing mechanism, dismantle the air filter with the supply pipe. Then the throttle actuator is disconnected, the fasteners are unscrewed, the carburetor is removed from the seat. Remote control cleaning:

  • Dismantle the body of the filter-settling tank. At the bottom, unscrew the fixing bolt, take out the glass. Inside it, oily deposits are cleaned out, everything is thoroughly wiped and dried.
  • A float chamber is made in the lower part of the body. In its center is the main fuel jet, which is unscrewed with a screwdriver. There is a small sleeve underneath, which is also removed. To remove the float with a closing needle, remove the support axle with pliers.
  • The carburetor body (with previously removed plastic parts) and jets are placed in acetone or white spirit for a day. Polymer components are washed with clean gasoline, cleaned with a soft brush, then dried thoroughly.
  • Soaked parts are cleaned of plaque with a rag, and the dispensing holes. with a thin needle or wire.
  • The assembly is carried out in the reverse order.
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Carburetor adjustment

During the operation of gasoline agricultural machinery, it is periodically necessary to adjust all of its components. It is necessary to adjust or clean the carburetor in the walk-behind tractor when the engine starts to malfunction or is unstable. In the equipment of different manufacturers, the remote control is adjusted individually. The sequence of the procedure, as well as methods of adjustment, depend on the model of the dispensing mechanism.

Correct setting and adjustment of the carburetor of the walk-behind tractor

The rated power of an internal combustion engine (ICE) is achieved with an optimal fuel mixture. The carburetor of the walk-behind tractor is responsible for the quality of the latter. a dosing device (DU), which mixes gasoline with air entering the cylinder. The amount of torque on the output shaft of the motor and the amount of exhaust gases depend on the adjustment. A step-by-step guide and a description of the principle of its operation will help to correctly adjust and configure the fuel unit.

“Neva” MB-1, MB-2

Motoblocks manufactured by ZAO Krasny Oktyabr are classic models developed in 1984. Farmers appreciate them for their unpretentious and high-torque engine, which is easy to maintain. A well-thought-out power system allows you to regulate the quality of the fuel mixture while the power unit is running. Progress:

It is not difficult to make an adapter for a walk-behind tractor with your own hands, if you collect everything you need for work, understand well.

  • Warm up the internal combustion engine at high speeds.
  • Unscrew the idle speed control screw (XX) until the engine starts to stall or stops.
  • Screw the regulator back slowly. The procedure is stopped when the revolutions are stabilized, and the sound of detonation of the fuel in the cylinder becomes clear and smooth.
  • To prevent the adjusting screw from unscrewing spontaneously, a little oil paint drips onto the edge of the thread.

The agricultural equipment of the Ufa enterprise. UMPO is designed for performing agrotechnical work on a farm. The popularity of the brand among users is due to the high quality of components and their assembly. In addition, the powerful engine allows you to process a large area of ​​land in a short time. Setting the carburetor of the “Agro” walk-behind tractor (“Agros”):

  • Drain fuel from the gas tank or close the fuel supply valve to the remote control receiving chamber.
  • Unscrew the glass of the float chamber. The part is fixed from the end with one bolt.
  • Remove the container, opening access to the float.
  • According to the data given in the ICE operation manual, the position of the locking mechanism is adjusted. If the latter does not provide proper tightness, perform an audit with replacement of damaged parts.
  • Assemble the knot in reverse order.


In order for agricultural machinery to work properly, it needs to be periodically audited. Maintenance of the fuel unit is reduced to cleaning the carburetor of the walk-behind tractor, checking the contamination of the air filter and fine-tuning elements of gasoline. Considering that the remote control provides fuel supply, and, therefore, drives the cultivator itself, you need to carefully monitor the state of this mechanism, properly care for it and carry out repairs in a timely manner.

Continuous monitoring of the remote control will prevent serious damage to sensitive components. In addition to adjusting idle speed, regular cleaning of both the outer surface and the inner cavities is carried out. During the audit, the condition of the moving parts and the calibration jets is checked. The former are subject to abrasion when interacting with each other, and the latter are clogged with dirt. If during disassembly deviations in geometric dimensions are found, the worn parts must be replaced.

The carburetor is an integral part of the chainsaw, the function of which is to mix the fuel mixture with.

Contamination of the nozzles occurs due to the ingress of foreign chemicals into the fuel system. Since the remote control interacts with gasoline and air, the cause of pollution can be in the first or in the second source. To reduce the intensity of sedimentation of dirt, additional filter elements are used, which are cleaned as they become dirty.

Power system design

One of the components of the internal combustion engine is the fuel system. It is necessary for the uninterrupted supply of the engine with fuel. The system consists of a gas tank, fuel line, filters and carburetor. The latter doses gasoline to maintain a given crankshaft speed, depending on the operating modes of the walk-behind tractor. The gas tank is necessary for storing fuel in it. Fuel lines connect all components to each other, and filters clean the fuel from impurities.

The most complex and critical part in the internal combustion engine is the dosing unit. The carburetor device installed on the walk-behind tractor allows the user to adjust the quality of the fuel mixture entering the engine. In general, the control system consists of the following:

  • Float chamber. It contains the parts responsible for the preparation of the fuel mixture. Gasoline accumulates in the receiving glass, which acts on the float. The latter, upon reaching a predetermined fuel level, by pressing the shut-off needle, cuts off the fuel supply.
  • Mixing chamber. In it, the air entering the engine is saturated with fine gasoline dust. The latter is formed due to the rarefied atmosphere in the mixing chamber. The reduced pressure draws fuel from the float chamber, which, passing through the metering nozzle, is atomized in the air stream.
  • Throttle body. This unit controls the crankshaft speed. The damper closes the passageway through which air enters the cylinder. The larger the section, the faster the output shaft of the internal combustion engine will rotate. The position of the damper is adjusted by means of a steel cable attached to the handle of the walk-behind tractor.
  • Idle speed regulator. Typically this is a metal or plastic screw that supports the throttle actuator. Screwing in the governor increases the engine idle speed.

Gasoline engine carburetor GAZ-3307

A K-135 carburetor is installed on a GAZ-3307 car. It is a modification of the K-126, having practically the same device, differing only in the diameter of the nozzles and in some variants of the diffusers.

Adjustment and tuning of the GAZ-3307 carburetor

According to the technical specifications, the fuel consumption of the GAZ-3307 truck with the ZMZ-5231.10 gasoline engine is 19.6 liters at a speed of 60 km / h, at a speed of 80 km / h, the consumption increases to 26.4 liters. But such indicators are almost impossible to achieve with a laden car, especially in urban conditions.

An example of a classic truck GAZ 3307

It should be noted that carburetors are currently being actively supplanted by injection systems, in which the regulation of the gasoline / air ratio is carried out automatically, but, nevertheless, there are still a lot of cars that use the traditional carburetor system. These include the GAZ-3307 truck.

K-135 device

The carburetor has a standard device. it has two chambers and, accordingly, two chokes. They are regulated by two screws, which allows you to adjust the quality of the mixture in the carburetor (and therefore idle speed) individually for each chamber. However, improper installation of the throttle plates can cause uneven operation of each of the groups of cylinders served by the carburetor, which means unstable engine idling.

diagram of the K135 carburetor device

The situation is saved only by the fact that the operating time in this mode for trucks is short. The flow of the combustible mixture in these carburetors is decreasing, which practically excludes the possibility of filling the engine and makes it easier to start in difficult conditions. In each of the carburetor chambers, a double atomization of the mixture occurs, the float chamber is balanced.

As already indicated at the beginning of the article, it is possible to install two models of the carburetor on the GAZ 3307. K135 and its modification K135MU.

The difference between the two carburetors is primarily the engine exhaust gas recirculation connection. Naturally, overpaying for an unnecessary function is not worth it, in the event that, of course, if your engine is not equipped with such a system.

This is how the model of the carburetor K135MU looks like

  • Aluminum throttle body (lower part);
  • Main body (which contains the float chamber);
  • Upper carburetor part (cover);
  • Limiter body.

The carburetor is a rather complex mechanism; several systems work in the K-135 for preparing the fuel-air mixture:

  • Main dosing system (main in the carburetor);
  • Float chamber;
  • Economizer system;
  • Accelerator pump;
  • Starting device;
  • Idling system;
  • Mixing chamber;
  • Crankshaft speed limiter.

Diagram of the carburetor device for Gas 3302

  • The main metering system ensures the preparation of the main fuel mixture at medium loads. System elements are located in the main body: fuel and air jets, diffusers.
  • The economizer system serves to enrich the mixture.
  • The accelerator pump adds a portion of fuel when the gas pedal is pressed sharply.
  • The starting device is associated with the choke and adjusts its position when starting the engine.
  • The idle system prepares the mixture to maintain the engine idle speed.
  • The float chamber maintains the fuel level required to prepare the fuel mixture.
  • The speed limiter prevents overloading the engine, limiting the load due to the fact that under the action of vacuum, the throttle valve does not open fully. Accordingly, the maximum engine speed falls.

Malfunctions affecting fuel consumption

The principle of operation of the K-135

The carburetor is used to prepare a high-quality fuel mixture. The air flow with gasoline is mixed in the required proportion, the proportion is set by the diameter of the diffusers and jets. The amount of the mixture also depends on the position of the throttle valve.

Carburetor models K135 and K135MU

Since the GAZ 3307 car was produced at a time when the Gorky Automobile Plant was moving towards the unification of parts and assemblies, this car uses a K135 or K135MU carburetor, which is also used in some other cars.

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An example of a K135 carburetor for GAZ 3307

However, the K135 model is more common on cars found today, which is why most mechanics dealt with it.


Carburetor malfunctions negatively affect engine performance. Signs of a problem with the carburetor:

  • Unstable operation of the internal combustion engine at idle, or the engine regularly stalls at these speeds;
  • Dips at medium speeds;
  • When the accelerator pedal is pressed sharply, the engine jerks and becomes bogged down;
  • ICE does not develop high revs;
  • Black smoke comes out of the muffler pipe;
  • Pops and shots are heard from the carburetor or exhaust pipe;
  • The engine only runs when the choke is half closed;
  • The motor “troit” and fills the candles;
  • The engine is difficult to start, and only when the gas pedal is pressed.

It should be noted that almost any carburetor malfunction is accompanied by increased fuel consumption.
There can be no question of an acceptable rate here, and with such a flow rate, the arrow of the fuel level sensor in the car’s interior rapidly approaches zero even at a speed of 60 km / h on a flat road.

Adjustment of the walk-behind tractor: carburetor, valves, fuel system

This article describes the adjustment of the walk-behind tractor, namely its main parts: the carburetor, valves and the fuel system. The process is not easy, so we have included some photos and videos as well. You can also read repair tips here.

Adjusting the carburetor of the walk-behind tractor

The instability of the engine speed of the walk-behind tractor indicates that the carburetor needs adjustment. The need to perform this procedure, as a rule, arises before the start of the agricultural season, when the equipment has not been used for a long time, or vice versa, when the cultivator has been subjected to significant loads for a long period of time.
Before proceeding with the adjustment, it is necessary to warm up the engine. The work process itself looks like this:

  • The screws regulating low and maximum throttle are screwed in completely, after which they are loosened by about one and a half turns.
  • The motor is started with a starting device or manually, and warms up for about 10 minutes.
  • The lever that controls the operation of the power plant must be set to the minimum position. But the motor should not stop at the same time.
  • The throttle throttle adjusting screw will help to adjust the minimum idle speed so that the diesel engine is stable, without extraneous noise and stops.
  • The rotation of the screws makes it possible to accurately set the amount of combustible mixture that enters the motor.
  • Tightening the propeller enriches the mixture, while unscrewing it, on the contrary, increases the volume of air entering the engine.

Using the idle screw, adjust the maximum idle speed. The same should be done with minimum speed, using the throttle stop screw. The essence of such an adjustment is that the shutter screw allows you to adjust the angle to which it is closed.

The lever responsible for controlling the motor should be moved to the “throttle” position. If the operation of the cultivator still cannot be called stable, the full throttle screw is adjusted until a perfect stroke is observed. However, the maximum permissible propeller speed is 2.5.

The accuracy of carburetor adjustment can also be determined by how the spark plug looks after a short period of time under load. If the working mixture is ideal, then there will be neither carbon deposits nor traces of fuel on the spark plug, which indicate that the combustible mixture is too lean, or, conversely, too rich. However, it should be noted that carbon deposits or traces of fuel on the spark plug can speak not only of incorrect adjustment, but also of more serious problems of the Chinese or domestic walk-behind tractor, including faulty ignition or cooling system.

Adjusting the valve clearance of the walk-behind tractor

Over time, with significant loads, the valve clearance of the engine of the walk-behind tractor changes. This may be due to wear on parts. Insufficient distance leads to the fact that the stages of gas distribution change significantly. As a result, it is not possible to achieve a sufficient compression ratio, and the power device operates intermittently, without reaching the declared power. In particularly serious situations, even deformation of the valves can be observed. If the gap is too large, significant mechanical noises are recorded, the gas distribution phases also change significantly, the valves open for too short a time, due to which the cylinder does not fill properly, the power drops, and failures occur. Clearance adjustment is necessary immediately, as soon as engine operation becomes incorrect or begins to occur with significant noise. Ideally, the engine being adjusted should be cooled down.

So, first you need to get to the flywheel. It is on this part that the value of the top dead center is marked. The flywheel is hidden under the cover, and therefore will have to be removed. Before removing the casing, the oil bath of the air filter is removed. It is possible to facilitate the task in the process of removing the casing if you fix all the latches with rubber bands. All bolted connections are unscrewed with a key, after which the cover can be removed without problems.

On the flywheel, you can see marks that indicate TDC, as well as values ​​of 5, 10 and 20 degrees. The 20 degree mark indicates the injection of the combustible mixture. The flywheel should be brought under the top dead center, focusing on the appropriate division. The valve cover is unscrewed and removed.

In the process of adjustment, you need to use the following tools:

  • screwdriver;
  • spanner key 10;
  • blade 0.1 mm thick.
adjust, walk-behind, tractor

According to the technical data sheet, the valve clearance of the walk-behind tractor engine is from 0.1 to 0.15 millimeters, and therefore, with the help of a blade, it can be adjusted very accurately. However, you need to pay attention to the fact that some blades are 0.8 mm thick. and this is unacceptable. The exact value can be found with a micrometer or from the information on the manufacturer’s website.

The adjustment is carried out as follows:

  • Using a screwdriver, we loosen the nut, insert the blade and begin to tighten.
  • We focus on the blade, carefully tighten the nut.
  • We adjust until the valve free travel is eliminated. It should fit snugly enough.
  • In the reverse order, we assemble the casing, put the oil bath in place by hand.

If all manipulations are carried out without errors, then the engine will run smoothly and without unnecessary noise.

Adjusting the fuel system of the walk-behind tractor

If no fuel is supplied to the cylinder, the first step is to check if there is enough fuel in the tank. You also need to check whether it goes to the carburetor. For this, a hose is removed from the inlet connection of the device. If we are talking about a carburetor type K45, you should press on its quench so that fuel begins to pour out through the drain hole.

If fuel does not enter the carburetor, then you need to turn off the fuel supply valve, completely disassemble it and remove accumulations of dirt from the mechanical filter. To achieve maximum cleanliness, all components must be treated with gasoline. The fuel cock is assembled and returned to its original location.

If fuel enters the carburetor, but the cylinders are not supplied, it is necessary to check the correct operation of the fuel valve, as well as the presence of dirt on the jets.

Grillo Walk-behind Tractor Handlebar maintenance

To deal with the carburetor of a gasoline walk-behind tractor of the KMB-5 type, you need to remove it from the engine and pour out the fuel from the float chamber. Through the fitting (see figure), with the help of which the gasoline is supplied, it is necessary to supply the air mixture, having previously installed the carburetor in the operating position. The passage of air should go unhindered, and when the carburetor is turned over, it should completely stop. These features indicate the full performance of the part.

Details in the figure: 1. fuel supply connection; 2. upper body; 3. throttle valve; 4. idle needle; 5. jet; 6. lower body; 7. air damper; 8. screw fixing the tie; 9. maximum gas needle; 10. spraying element; 11. float; 12. fuel supply valve.

The fuel level inside the float chamber can be adjusted using the float tab. Ideally, it should range from 3 to 3.5 centimeters.

To purge the nozzles, it is necessary to unscrew the screws responsible for full and low gas.
Cleaning the carburetor parts begins by loosening the screws holding the upper housing. The lower body is removed, the fuel supply valve is flushed with gasoline, and the dirt from the nozzles is blown out by a pump. It is necessary to check if the float is intact. It is absolutely impossible to use rags in the cleaning process.

After completing the cleaning, the housings are connected. It is necessary to check that the spray tube is clearly inserted into the hole located on the upper body. Open the throttle valve and check how well the assembly is done. The screws that secure the upper case are tightly tightened. After the assembly process is completely completed, the carburetor should be adjusted. This will significantly improve the performance of a heavy walk-behind tractor with attachments, since for correct operation, perfect adjustment of all its parts is required.

If the carburetor DM 1.08.100 is installed on the engine of the cultivator, then the procedure for adjusting it will be as follows:

  • Screw in the screw 10 (Fig. 3) at idle until it stops and unscrew it half a turn.
  • Then you need to tighten the full throttle screw 9 and completely unscrew it by 2 turns.
  • Unscrew the screw 4 (Fig. 4) of the minimum engine speed right up to the stop of the lever against the bore of the carburetor body and tighten it 2 turns.
  • Start the engine of the walk-behind tractor, and then adjust stable operation at maximum speed after warming up with screw 9.

Do not disengage the engine control lever. Move it to the position of minimum throttle (rpm) and, by unscrewing screw 10, set stable idle rpm. This completes the setup.

This is, in principle, all the repairs. The main points of adjusting the main parts of the walk-behind tractor are considered. Use our manual (instruction) and prevent faults. Enjoy adjusting your walk-behind tractor or cultivator!