Carburetor for 151 and letter modifications. Recommendations for repairing the K151 carburetor

Carburetors K-151V are used to complete the UMZ-4178 engines, and K-151U are used to complete the ZMZ-4021.60 engines. The K-126GU carburetor is used to complete the UMZ-417 engines, as an option to replace the K-151V carburetor.

In principle, the K-126GU carburetor is similar to the K-151V carburetor, but has a simpler design in which there is no forced idle economizer system and a float chamber ventilation valve.

Carburetors K-151V, K-151U and K-126GU for UMZ-417 and ZMZ-4021.60 engines, device.

Carburetors are vertical, emulsion, two-chamber, with a falling mixture flow and sequential opening of the throttle valves. All carburetors include:

- balanced float chamber,
- two main dosing systems - the first and second chambers,
— autonomous idle system in the primary chamber with quantitative regulation of the mixture of constant composition with a forced idle economizer (EFCH),
— transition systems of the primary and secondary chambers,
— econostat with output to the secondary chamber,
— a diaphragm accelerator pump with a mechanical drive from the throttle valve shaft of the primary chamber and with a nozzle outlet into the primary chamber,
— semi-automatic system for starting and warming up the engine with manual control,
- in addition, K-151V and K-151U carburetors are equipped with a float chamber ventilation valve.

Maintenance of carburetors K-151V and K-151U.

It consists of periodically checking the reliability of fastening of the carburetor and its individual elements, checking and adjusting the fuel level in the float chamber, adjusting the low speed of the engine crankshaft, cleaning, purging and flushing carburetor parts from tar deposits, checking the throughput of the jets.

Checking the fuel level in the carburetor float chamber.

It is carried out with the car engine not running, installed on a horizontal platform and with the carburetor cover removed. The float chamber is filled with fuel using a manual pumping lever.

The fuel level should be within 20-23 mm from the plane of the float chamber connector. To check it, you need to screw in a fitting with an M10x1 thread to connect the rubber hose. The fitting is screwed into the float chamber instead of the drain plug. The fuel level is determined through a transparent tube with an internal diameter of at least 9 mm.

The level is adjusted by bending the tongue of the float loop to a size of 10.75 -11.25 mm between the top of the float and the plane of the float chamber connector; the float should be raised to its highest position. In the lowest position, the float should not touch the walls of the float chamber, and its tongue should be on stop A. In this case, the stroke of the fuel valve should be equal to 1.5 + 0.5 mm. The valve stroke is adjusted by bending the tongue of the float loop.

After adjustment, you need to check the fuel level again and, if necessary, adjust again. If the adjustment does not give the desired result, it is necessary to check the float mechanism. Typically, the reasons for an increased or decreased fuel level in the float chamber are unsymmetrical float, incorrect weight, as well as a stuck or leaky fuel valve.

The tightness of the float is checked by immersing it in water heated to 80-85 degrees with a holding time of at least 30 seconds. The mass of the float assembly with the loop after repair should not exceed 13 grams. If the fuel valve is not tight, the sealing washer should be replaced. After replacing the sealing washer, when assembling the fuel valve with the earring, it is necessary to take into account that the earring must be installed so that the protrusion of the earring B is directed in the direction opposite to the float.

Adjusting the minimum crankshaft speed in idle mode.

It is carried out on a warm engine at a coolant temperature of at least 70 degrees and in good condition. During vehicle operation, the minimum idle speed is adjusted by turning the operational adjustment screw. When unscrewing a screw, the rotation speed increases, and when screwing it in, it decreases.

If it is not possible to achieve stable engine operation by rotating the operational adjustment screw, you should unscrew the mixture screw until the stop of the limiting sleeve pressed onto the screw and again adjust the minimum frequency with the operational adjustment screw.

Full carburetor adjustment.

The K-151V and K-151U carburetors are fully adjusted at a service station using gas analysis equipment and should be done under the following conditions: on a warm engine, with adjusted clearances in the mechanism, with serviceable ignition and an adjusted ignition timing, with the air damper fully open .

Adjustment sequence:

1. Adjust the minimum idle speed with the operational adjustment screw to 550-650 rpm.
2. Adjust the mixture composition screw to adjust the carbon monoxide (CO) content within 1.0 -1.5%, having previously removed the restrictive sleeve; the hydrocarbon (CH) content should not exceed 1000 ppm.
3. Make sure that the selected position of the screws ensures normal operation of the engine during throttle changes; to do this, open the throttle slightly and release it sharply; if at the same time the engine stops or is running, then it is necessary to either increase the minimum rotation speed by unscrewing the operational adjustment screw, or enrich the mixture
screw of the mixture composition, the maximum permissible CO content should be no more than 2%.
4. Increase the rotation speed to 2400 rpm, the CO content should be no more than 1%, CH - no more than 500 ppm.

After the final adjustment, install a limiting sleeve on the mixture adjustment screw and mark its position. Warm up the engine to a coolant temperature of 80-85 degrees and check the CO content in the exhaust gases at idle speed of 550-650 rpm.

Washing carburetor parts.

Carburetors are washed with gasoline followed by compressed air. Do not use metal wire to clean jets and calibrated holes, as this will disrupt their dimensions and capacity.

In order not to confuse the jets during installation, you should pay attention to their markings. Each jet is marked with the nominal flow rate in ml/min. The marking is applied by impact on the nozzle head from the spline side.

Nominal flow rate of the jets for the K-151V carburetor, ml/min.

— Main fuel jet: 1st chamber — 225, 2nd chamber — 330
— Main air jet: 1st chamber — 330, 2nd chamber — 230


— Emulsion idle jet: 1st chamber — 280

Nominal flow rate of the jets for the K-151U carburetor, ml/min.

— Main fuel jet: 1st chamber — 225, 2nd chamber — 380
— Main air jet: 1st chamber — 330, 2nd chamber — 330
— Idle jet block:
idle tube: 1st chamber - 95
emulsion tube: 1st chamber - 85
— Idle air jet: 1st chamber — 330
— Emulsion idle jet: 1st chamber — 210
— Fuel jet of the transition system: 2nd chamber — 150
— Air jet of the transition system: 2nd chamber — 270

When checking the operation of the K-151V and K-151U carburetors, you need to pay attention to the operation of the float chamber ventilation valve, the reliability of the wire connections, the absence of jamming and the tightness of the valve. A malfunction of the valve leads to increased fuel consumption and difficulty starting a hot engine.

Maintenance of the K-126GU carburetor for the UMZ-417 engine.

Maintenance of the K-126GU carburetor is similar to maintenance. Adjustment of the minimum idle speed of the crankshaft is carried out in the following sequence:

- tighten the screw that changes the composition of the mixture all the way, but not tightly, and then unscrew it 1.5 turns,
- start the engine and use the throttle valve thrust screw to set a stable crankshaft speed of 550-650 rpm,
— the limit value of carbon monoxide is adjusted with the toxicity limiter screw.

Nominal flow rate of the jets for the K-126GU carburetor, ml/min.

— Main fuel jet: 1st chamber — 240+-3.0, 2nd chamber — 350+-4.5
— Main air jet: 1st chamber — 280+-3.5, 2nd chamber — 280+-3.5
— Idle fuel jet: 1st chamber — 50+-1.0, 2nd chamber — 95+-1.5
— Idle air jet: 1st chamber — 285+-4.0, 2nd chamber — 285+-4.0

Carburetors K-151d and K-151s are considered one of the most reliable devices. When used correctly, they work properly for a long time and do not require special maintenance. However, for optimal performance, this device must be adjusted correctly. The performance of the power unit depends on this process. Carburetor K-151s adjustment allows you to improve efficiency, increase power and.

Carburetor problems

Most malfunctions are usually associated with improper adjustment or clogging of the calibration holes with small particles or hard resinous deposits.

• . The problem may not be with the carburetor itself, but with the condition of the wiring between it and the accelerator pedal. For accurate diagnostics, it is necessary to disconnect the wire from the device and manually move the throttle with the engine running. If the speed has dropped to the desired limit, the problem is in the wire. When this does not happen, check the carburetor for corrosion and contamination.
• Gasoline leak. The cause of the malfunction most often lies in problems in the float chamber, increased pressure or adjustment of the float position. Check the fuel pressure, if it is normal, look for a problem in the float chamber.
• Fouled spark plugs. is a sign of excess fuel supply. This could be due to a faulty valve or incorrect fuel level. In the second case, you need to adjust the float and check the pressure.

Video - Design and operation of the K-151D carburetor

Complex adjustment of the K-151d carburetor includes the following activities:

• adjustment of the float chamber (PC);
• adjustment of the starting device (PU);
• adjustment of the idle speed system (idle speed).

PC adjustment

First you need to remove the carburetor cover. At least a quarter of the fuel is sucked out of the float chamber using a rubber bulb. Then set the engine crankshaft to a position that locks. Start pumping the fuel mixture manually. Once the level stabilizes, stop the operation. The liquid mirror should be at a height of 3 cm from the upper edge of the middle part of the carburetor. To increase the fuel level to the required level, use a screwdriver to slightly bend the float tongue upward without removing it. To reduce the level, the tongue must be bent down. In this case, you need to hold the float so that it does not rise.

After making the adjustment, perform a secondary fuel level check. It must match the parameters recommended by the manufacturer. This setting does not need to be done regularly. The cause of the violation may be natural wear and tear of the device elements or unqualified intervention.

PU adjustment

The adjustment can be performed both on a removed carburetor and on the device located in its standard place in the car.

Adjusting the PU on a previously removed carburetor. First, you need to slightly open the throttle by turning it all the way and locking the trigger control lever. Then we release the shutter and, using a drill or other tool, check the gap between the edge of the damper and the chamber wall. It should be within 1.65 ± 1.5 mm. To correct this gap, first unscrew the lock nut and then rotate the stop screw. It must be remembered that for correct operation of the mechanism, the plane of the screw head must always be in a position perpendicular to the plane of the cam. In other words, the screw should be rotated in multiples of half a turn.

Following this, we adjust the thrust, which connects the air damper axis to the PU control lever. When the damper is fully closed, the gap between the levers should be 0.5 ± 0.3 mm. If necessary, increase or decrease the length of the rod by rotating its head.

At the next stage, we check the gap if there is a vacuum. Without releasing the PU control lever, use a screwdriver to recess the rod and measure the gap at the lower edge of the damper. Its value should be within 6.5 ±0.5 mm. If necessary, adjust the gap by rotating the screw, which tightens the halves of the PU lever.

Adjusting the PU on a car. First, remove and start the engine. Then gently press the gas pedal and pull the throttle control lever towards you as far as possible. At maximum opening of the air damper, the engine speed should be within 2600 ±1000 rpm. If the rotation speed goes beyond these limits, unscrew the locknut and turn the stop screw of the first chamber remote control lever in one direction or another until the required speed is reached. After this, tighten the locknut.

Note. Due to the difficult access to the screw, experienced drivers perform this adjustment by carefully bending the PU control lever.

Video - Adjusting idle speed on K-151d

The essence of the XX setting is that the carburetor ensures stable engine operation with minimal CO2 emissions in the exhaust gases. Ideally, adjustments are recommended to be made using a gas analyzer. However, quite satisfactory results can be achieved by performing the setup without this device.

On a preheated engine, with the screw regulating the amount of fuel mixture in a fixed position, rotate the quality fitting until the engine speed reaches the maximum value. Then, by rotating the quantity screw, we increase the rotation speed by 110 ± 10 rpm higher compared to normal engine speed in idle mode. After this, turn the quality screw and reduce the speed by 110 ± 10 rpm.

Compared to the 151 (151d) series, the K-151s carburetor has the following design features:

1. improved small diffuser, which has more stable characteristics and allows you to create greater vacuum;
2. the accelerator pump has nozzle outlets in both chambers;
3. The continuously variable PU drive provides more flexible engine control during starting and warming up, and also eliminates the need to press the accelerator pedal before starting a cold engine.

K151S is a carburetor developed and manufactured at the Pekar plant (formerly the Leningrad Carburetor Plant). This model is one of the modifications of the 151 line of carburetors of the named manufacturer. These units are designed to work with the ZMZ-402 engine and various modifications of these internal combustion engines. After some modifications and upgrades, the K151S (a new generation carburetor) could work with engines such as the UMZ-417 and many other units of a similar design.

This device is equipped with most modern systems and mechanisms designed to improve technical, operational, and environmental characteristics. Let's consider the design of the device, the principle of operation, methods of repair and adjustment.

Design

K151S is a carburetor that is equipped with two metering devices in the first and second fuel chambers. This model is also equipped with an idle speed system, a semi-automatic starting system, and an economizer. The design includes an accelerator pump that sprays fuel into the first and second chambers. Along with other systems, there is an EPHH with a pneumatic drive and electronic control.

What is special about the continuously variable semi-automatic starting system? Thanks to it, you no longer need to press the gas pedal to

The unit has two vertical air channels. At the bottom of them there is a throttle valve. These channels are called carburetor chambers. The throttle valve and its drive are designed in such a way that as you press the accelerator, first one circuit opens, and then the other. This is a two-chamber carburetor. The circuit whose damper opens first is called the primary circuit. Accordingly, next comes the secondary camera.

In the middle part of the main channels for air passage, special cone-shaped narrowings are installed. These are diffusers. Due to them, a vacuum is formed. It is necessary so that during the air movement there is a suction of fuel from the carburetor float chamber. In order for the device to function normally and prepare the optimal mixture, the level of gasoline in the chamber is constantly maintained. This is done using a float mechanism and a needle valve.

How the carburetor works consists of three main parts. The top one is the housing cover. It is equipped with a flange and studs, a device for ventilating the float chamber, as well as parts of the starting system.

The middle part is the unit body itself. Here is the float chamber, float mechanism, and fuel supply systems. In the lower part there are throttle valves and their bodies, and an idle speed device.

Main dosing system

There are two of these systems. They have the same design. The systems are equipped with fuel jets. The reader can see them in the photo below.

The main jet is installed on the top of the housing. To be more precise, in the area of ​​emulsion wells. There are 2 emulsion tubes under the air jets.

The walls of the emulsion wells have holes that are connected to the outlet nozzles. Due to the vacuum in the area of ​​the nozzle holes, the fuel rises through the emulsion wells. Then it passes to the holes in the tubes. The fuel is then mixed with air in the central part of the tubes. After this, it goes through the side channels to the nozzles. There the fuel mixes with the main air.

Idle system

It is needed to ensure stable engine operation at idle speed. The system consists of several elements:

1. The screws with which the
2. Fuel and air jets.
3. Economizer valve.

Acceleration pump

It allows the engine to operate stably throughout the entire range, without dips when pressing the accelerator pedal sharply.

The pump consists of additional channels in the carburetor body, a ball valve, a diaphragm mechanism and a spray gun.

Econostat

This system is necessary to increase the stability of the power unit at high speeds by enriching the fuel mixture. These are several additional channels through which, due to the high vacuum when the dampers are fully open, additional fuel is supplied.

Transition system

It is necessary so that the engine speed at the moment the throttle of the secondary chamber opens can increase more smoothly. The transition system consists of a fuel and air jet.

Optional equipment

That's what the K151S is all about. The carburetor is additionally also equipped with a filter in the form of a protective mesh. The unit also has a return fuel channel. Through it, excess gasoline goes into the gas tank.

Differences between the K151S and the basic K151 carburetor

We looked at how the K151C carburetor works.

Its design, at first glance, is practically no different from the entire 151st series. However, there are still minor differences. Thus, the small diffuser has a more advanced design. The carburetor uses an accelerator pump spray for two chambers at once. The developers also changed the profile of the cams on the pump drive. The air damper drive is now continuously variable. This allows you to significantly simplify the engine. We also changed the settings of the dosing systems. Thanks to this, it was possible to improve environmental performance.

K151S is a more efficient carburetor than K151. So, with it the dynamics of the car improved by 7%. Fuel consumption fell by up to 5% when driving in the urban cycle. Engine starting has improved significantly, and engine idle performance has also stabilized.

How to connect a carburetor?

Owners of old cars often do not know how to connect this device. The K151C carburetor is connected as follows.

The design has 2 hoses. The main fuel pipe is connected to the fitting located under the float chamber - the one closest to the engine. The return fuel channel will be connected to the lower outlet. It can be seen on the side opposite the engine, lower than the main fitting.

You also need to connect two more thin hoses. One of them can be connected to the idle speed economizer valve. This is the hose that comes from the solenoid valve. The second is connected to the lower fitting on the reverse side of the throttle valves.

You also need to connect the OZ hose to the distributor. The carburetor has a fitting for the positive crankcase ventilation hose. It also needs to be connected.

Carburetor K151S: repair, adjustment

Several types of adjustments are made. So, you can adjust the idle speed, the fuel level in the float chamber, the position of the throttle and air dampers.

The fuel level is changed by bending the float. The parameter is measured on a special surface in the float chamber. It is better to entrust this operation to professional craftsmen, but if necessary, you can do it yourself.

To adjust the idle speed, it is necessary to warm up the engine to its operating temperature. Next, open the throttle valve and unscrew the adjusting bolts:

• quantity screw with spring;
• quality screw.

The engine will pick up speed. Then the screws are tightened until the motor becomes unstable. Then use the quantity bolt to increase the speed until the engine runs smoothly. The adjusting mechanism, which is responsible for quality, is tightened until it stops. What do they do after that?

Next, the speed screw is tightened so that the motor runs stably at 700-800 rpm. If the quantity screw is tightened more, then there will be If the speed is high, they are reduced by adjusting the throttle position.

Conclusion

We looked at the carburetor of the 151C model. Repairing the K151C carburetor and adjusting it, as you can see, can be done with your own hands. This is convenient if the breakdown occurred far from a service station or home. And even beginners can service the carburetor.

Carburetor K 151: device, repair, adjustment

Fuel consumption directly depends on the condition of the fuel system, and if there are faults in it, the car's dynamics also deteriorate and the engine begins to operate unstably.

This article will discuss the K151 carburetor: design, repair, adjustment, configuration features, as well as the main problems and their symptoms.

K-151 carburetor design

In the fuel system, the carburetor of the K-151 model performs the function of preparing the air-fuel mixture in the composition necessary for the operation of a car engine under various loads - at idle, at medium or maximum speed. This unit is used on Volga and IZh passenger cars, Gazelle and Sobol commercial vehicles, and UAZ SUVs. There are various modifications of the “one hundred and fifty-first”, and depending on its model, a letter is added to the name at the end, for example, the GAZ-3102/31029, GAZ-3302 “Gazelle” cars are equipped with the K-151S carburetor. Also, depending on the K-151 model, jets can be installed with different sections - much depends on the characteristics and size of the engine.

The 151 series carburetor consists of the following systems and elements:

• main body (middle part) with a float chamber;
• throttle body – the valves rotate due to the drive connected to the accelerator (gas) pedal;
• the top cover of the float chamber - it contains a locking mechanism that prevents the chamber from overfilling with gasoline, as well as an air damper necessary for starting a cold engine and warming it up;
• main dosing system - is the main one in the preparation of the air-fuel mixture (FA), consists of channels of a certain cross-section, two fuel and two air jets;
• idle system, which is necessary for stable operation of the internal combustion engine at idle speed - it includes a bypass channel, adjusting screws (quality and quantity of fuel assemblies), jets (fuel and air), an economizer valve with a membrane mechanism;
• accelerator pump - it allows the car to drive without failures during sudden acceleration, consists of additional channels in the main body, a ball valve, a diaphragm mechanism and a fuel sprayer;
• econostat - the system is designed to enrich fuel assemblies at high engine speeds; it represents additional channels through which, under the influence of high vacuum when the throttle valves are open, an additional portion of fuel enters the intake manifold;
• transition system - it is needed for a smooth increase in speed at the moment the throttle valve begins to open in the secondary chamber; it consists of fuel and air jets.

The K-151 carburetor consists of two chambers, the throttle valves in it open sequentially, and a filter - a protective mesh - is installed at the inlet of the fitting. The unit is also equipped with a return fuel line, through which excess gasoline is discharged back into the gas tank; also, the “return” does not allow the creation of excess fuel pressure. The design of the K-151 carburetor itself is quite complex, and in order to repair and adjust the unit, you need experience and strict adherence to the repair instructions.

Connecting hoses to the carburetor

Several hoses of two diameters are connected to the K-151 carburetor - if they are mixed up, the engine will not work properly. We connect the hoses in the following order:

Adjusting the K-151 carburetor

If without experience it is quite difficult for car owners to repair the K-151 unit with their own hands, then it is easier to master the adjustment, the main thing is to understand the principle of operation of the device and act according to the instructions. There are several types of “one hundred and fifty-first” adjustments:

• idle move;
• air damper position;
• gasoline level in the float chamber;
• throttle position.

Changing the fuel level in the float chamber should be trusted to experienced carburetor specialists, but any driver can adjust the idle speed independently. We carry out the procedure as follows:

If the engine speed is high, you should reduce it using the screw that adjusts the position of the throttle valves. This screw often boils tightly, and it is impossible to turn it in any direction (in the picture below, under the number 4, under the white paint).

There is one “tricky” way to force the adjusting element to turn - you need to install a flat-head screwdriver in its slot and carefully hit it several times with a hammer (you need to feel the force, otherwise you can break parts of the carburetor). The screw will “come away” and begin to rotate on the thread. If the “trick” does not work the first time, it should be repeated. It is important to take your time and be patient, then everything will work out.

Carburetor repair K-151

During the operation of the car, various malfunctions may occur in the carburetor; the main signs of malfunctions in this device are:

• increased fuel consumption;
• black smoke from the muffler pipe, it is especially noticeable if you press the gas pedal sharply;
• unstable operation at idle, the engine may also stall when the speed is reduced;
• poor car dynamics;
• failures when accelerating.

If the carburetor is faulty, the engine may not develop speed, and popping noises and shots from the muffler are often heard in the intake manifold. K-151 is a rather complex unit, and almost any of its elements can fail.

There are reasons why a carburetor most often fails:

• jets, fuel and air channels become clogged;
• heating causes deformation of the body;
• the float chamber shut-off valve stops working;
• Over time, the jets wear out.

Many repairmen, when restoring the functionality of the carburetor, first of all try to replace the jets, believing that because of them, fuel consumption increases and the engine runs unstable. One rather important note - the jets wear out very rarely, and most often wear occurs when the carburetor is often operated in dusty conditions. The most common reason for poor carburetor performance is its clogging, but in order to thoroughly clean the unit, it is necessary to completely disassemble it. Repair of the K-151 carburetor is carried out with the removal of the device, complete washing and purging of all its parts.

Problems with the carburetor when installing gas equipment

Often, car owners switch cars with carburetor engines to gas; for example, it is profitable to install LPG on a working Gazelle. But with constant use of gas in the carburetor, various types of problems appear, and one of them is a malfunction of the cold start system on the carburetor.

On many cars, the gas system uses a gas spacer for the K-151 carburetor; it is placed between the main body and the throttle body. Due to the additional insert, the distance between the lower and upper parts of the carburetor increases, so the cold engine starting system begins to work irregularly - you have to constantly keep your foot on the gas pedal, while holding the choke. On gas, a choke that is not fully working does not affect the operation of the engine, but the whole point is that cold starts of the engine, and especially in winter, are carried out on gasoline. Therefore, it is quite problematic to start the internal combustion engine with the air damper not completely closing; even due to the resulting vibrations, the fastening of the damper axis is often unscrewed. How to get rid of such an unpleasant problem?

One of the options for solving the problem is to weld an additional strip onto the air damper rod, which allows you to compensate for the difference in the thickness of the standard gasket between the housings and the gas spacer.

The bar can be made from an electrode with a diameter of 2 mm.

Replacing the K-151 carburetor

If the parts are severely worn, the carburetor needs to be replaced; most often it is changed if the housing wears out:

• the lower surface of the middle part is severely deformed;
• the cover (upper part of the body) is warped;
• The seat for the throttle valves in the lower part wears out.

The price of a new K-151 carburetor is quite high (on average 5.5-6.5 thousand rubles), but it is impossible to drive with a faulty device, especially since with high fuel consumption even more money is lost. Changing the K-151 is quite simple; let’s look at the process of replacing it on a Gazelle car:

Accelerator pump repair

If malfunctions occur in the carburetor accelerator pump, the engine begins to “choke” and failure occurs when the engine speed increases sharply. Quite often, the reason for such operation of the internal combustion engine is a clogged “nose” of the fuel nozzle; the accelerator pump diaphragm can also fail.

Diaphragm defects are determined by its external inspection; it can be easily reached without removing the carburetor from the engine. To do this, you need to unscrew the four screws of the cover (number 11 in the picture below), but you need to remove it carefully - it is important not to lose the spring, which is located inside the unit.

To determine the serviceability of the accelerator pump atomizer, you need to remove the air filter housing, turn the throttle valve by hand and see if fuel flows through the “spout” of the accelerator. If the nozzle is clogged, you can try to blow it out, but this will require removing the carburetor cover. If the spout does not blow through, it should be replaced; the work of replacing it is also carried out without removing the entire assembly. We replace the accelerator pump nozzle as follows:

Replacing the needle valve in the float chamber

If the engine consumes a lot of fuel, one of the reasons for this phenomenon may be a faulty needle valve in the float chamber - it is not sealed, and too much gasoline enters the chamber. In some cases, the valve completely stops holding fuel, then the carburetor is completely filled with gasoline, and the car does not start. Changing the needle valve is very simple:

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The K-151 carburetor was often installed on Russian passenger cars and light duty vehicles. These units are produced by Pekar LLC. The manufacturer believes that these are the best and most reliable carburetors of all existing ones. The plant produces three versions of devices for installation on four-cylinder power units ZMZ and UMP with a volume of 2.45 liters. Due to the complexity of the K-151 carburetors, adjustment and repair caused certain difficulties for the owners.

Device

There are two channels in the body of the device - these are the carburetor chambers. At the bottom of each there are mechanically driven valves. There are two chambers in the carburetor. The throttle valves open sequentially one after another as the load increases. The first chamber and its damper operate under low and medium loads. The second camera only works at high levels.

There are diffusers in the middle part of the body. They are designed to create a vacuum, which will then facilitate the intake of gasoline from the carburetor float chamber.

The design of the float chamber of the K-151 carburetor on the UAZ differs from any similar domestically produced devices. The mechanism along with the locking needle is located inside the housing. To visually check the condition of the camera, you need to remove the top cover. In this case, there is no need to disrupt the interaction between the float and gasoline. This design is called a bottom-fed float chamber.

Design Features

The device consists of three separate parts. The top serves as a lid. There are studs on it through which the air filter is installed. In addition, the cover contains balancing holes for the float chamber, parts of the trigger mechanism, and screws for fastening to the body.

In the middle part there is a float chamber of the mechanism, a fuel supply fitting to which the hoses of the K-151 carburetor are connected, as well as a dosing system.

At the bottom there are throttle valves and their mechanism, as well as a device that allows the engine to idle. It is secured with screws through cardboard and textolite spacers. The device also contains other systems, without which the operation of the device would be impossible.

Features of the float mechanism

This mechanism is needed to ensure that there is always a certain level of fuel in the float chamber. The gasoline level must be maintained so that the engine can run smoothly. If there is less fuel, the mixture will become lean, which will affect fuel consumption. The level is controlled using a float and a special valve. When the level is normal and the float is raised, the valve will be closed and will not allow a new portion of gasoline to enter.

When the fuel level is insufficient, the float will move down and open the needle valve, thereby allowing access to gasoline. As the chamber fills, the float will rise up. As a result, the needle valve will close.

At the same time that fuel consumption is not constant, its supply from the fuel pump also changes. This eliminates the increase in pressure at the carburetor inlet. The level in the float chamber is not constant and is not maintained in different operating modes of the motor.

GDS - main dosing systems

The GDS in the first and second chambers of the carburetor have the same design. Dosing systems consist of fuel and air jets of the carburetor. In K-151 they are installed in the lower part in the float chamber. Under the jets in two chambers there are emulsion tubes.

Idle system

This is a completely autonomous system for preparing the mixture. It provides intensive atomization of gasoline in the air flow entering the combustion chambers in idle mode. Thanks to this system, the engine can operate stably with closed or covered throttles.

Often it is with this system that many people have problems. Without knowing the structure of the K-151 carburetor, repairing and adjusting the idle speed can cause a lot of difficulties (especially on dirty, unmaintained carburetors).

Installation

The carburetor is installed on the manifold and bolted. The seat on cars is designed specifically for this carburetor model.

Next you need to connect the hoses, of which there are several, and they are connected in a certain order. So, the main pipe will be connected to the fitting under the float chamber. The return is connected to the lower outlet. Thin hoses come from the EMC. One of these pipes is connected to the economizer valve XX. The second connects to the lower fitting located on the other side of the damper body. Another output will be connected to the vacuum regulator UOZ.

Typical faults

There are not that many malfunctions with carburetors. Knowing the structure of the K-151 carburetor, repair and adjustment will not cause difficulties even for beginners. Malfunctions are due to incorrect adjustment or incorrect repairs.

So, one of the most important faults, which is very difficult to eliminate, is increased fuel consumption. Also, the exhaust gases may be dark or black. Loss of dynamics indicates a malfunction in the power system. Another popular fault is idle speed. It either disappears completely, or the engine cannot operate stably at idle.

Most often, most problems can be solved by cleaning the K-151 carburetor jets. Air and fuel jets can become clogged due to low-quality gasoline, old hoses, and dirty air and gasoline filters.

Another reason why the engine may be unstable is carburetor overheating. The metal of the unit body is very soft and is easily deformed due to overheating. As a result, a gap forms between the cover and the body. Excess air is sucked in through it, and it is not possible to adjust the carburetor in any stable way. Often the cause of a malfunction of the K-151 carburetor can be wear and tear on elements and components. This applies to rubber membranes, springs, and jets.

Engine stalls at idle

Most often the cause is a clogged idle fuel jet. It is located on the solenoid valve. The solenoid valve itself is also the cause. If the element is working, but there is no idle speed, then you need to clean the jet and the XX channel. Knowing the structure of the K-151 carburetor, repairing, adjusting and tuning it will not require much time.

What to do if it fills with fuel?

The cause of the large amount of fuel may be the needle valve. If the needle is worn out, it can no longer hold fuel pressure and it enters the float chamber. To repair, you need to remove the cover, remove the float axis, unscrew the valve and replace it with a new one.

Failure

When you press the gas, the engine does not pick up speed, slows down and may stall - such failures occur most often due to a clogged GDS.

This malfunction can be eliminated by cleaning the main dosing system. Dips can also be due to problems with the accelerator pump. Worn elements should be replaced and the channel cleaned with compressed air.

Conclusion

Installing a K-151 carburetor instead of the old K-126 will give a significant increase in power and good fuel economy. With regular maintenance, this carburetor will not cause unnecessary problems to the owner. Repair consists of replacing repair kits.