K-151 carburetor: device, adjustment, features, diagram and reviews

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

At the dawn of the production of GAZ and UAZ-31512 passenger models, K-126 series carburetors were installed along with power units. Later, these engines began to be equipped with elements of the K-151 series. These carburetors are manufactured by Pekar JSC. During their operation, both private car owners and enterprises encountered certain difficulties in repair and maintenance. The fact is that the design of the K-151 carburetor was significantly different from previous models. At the same time, information about the design features was very scarce.

General data on 151 series machines

Structurally, the elements of the K-151 series are seriously different from all other domestic carburetors, although their components and some systems are designed on the basis of typical schemes.

Depending on the time of release, the units of this series had several more design options. Below weconsider the features of the K-151 carburetor.

General device information

The unit has two adjacent vertical channels. They are necessary for the intake of oxygen. At the bottom of each of the channels is a throttle valve. Each of them is a carburetor chamber. The drive on the throttle valve is designed in such a way that as you press the pedal, one damper opens first and only then the other. The chamber whose damper opens first is called the primary chamber.

In the middle part of each of the channels for the passage of air there are special constrictions in the form of a cone. These are diffusers. What are these elements for? Due to them, a rarefaction effect is created, on the basis of which the fuel from the float is sucked into the system. The level of gasoline in the chamber required for the carburetor is maintained using a special mechanism with a needle valve and a float. We will talk about this in more detail.

Float with bottom fuel feed

It should be noted that on K-151 carburetors this mechanism is fundamentally different from the same device in any other domestic units. In this regard, the owners are experiencing problems with maintenance. This has been repeatedly stated in the reviews. By the way, this element was installed on old motors from ZMZ.

So, the system, together with the float and the needle valve, is housed in the body of the device. Visual control of the operation of the mechanism is possible only after removing the cover. In this case, the natural interaction of the float with the fuel level will not be disturbed. Thisthe design is called a bottom feed chamber.

Device

So, let's take a closer look at the K-151 carburetor. Carburetor device, repair, features are described below. The element is made up of three parts. The upper one is a body cover equipped with a flange, as well as studs for mounting an air filter with a float chamber ventilation device and elements of a starting system. The latter, through seven screws, is fixed to the case through a paper gasket.

There is a middle part in the carburetor device. This is directly the body of the device, where the float mechanism, the chamber and the fuel supply fitting are integrated. Also included is a dosing system.

The lower part of the unit includes the throttle body along with the actuator, the idle device, which is attached to the body via a gasket.

Float mechanism

When there is less fuel in the chamber than necessary, the float goes down, thereby freeing the needle. Due to this, the section opens and the flow of gasoline is ensured. As the chamber fills, the needle valve will close.

Together with the change in fuel flow through the needle valve in automatic mode, the supply of gasoline from the pump also changes. This eliminates the increase in fuel pressure at the inlet to the unit.

The fuel level is never saved - it changes depending on the engine operating mode. So, the maximum level will be at idle. When operating at full power, the level is slightlydecreases. This does not affect the efficiency of the device in any way, as it is necessarily taken into account in the process of adjusting the dosing system at the manufacturer.

Dispensing systems

What is for the first chamber of the carburetor, what is for the second, the design of the dosing systems is the same. How is it organized? There are main fuel jets, which are installed at the bottom of the float chamber, and main air jets. The latter are on the plane, in the upper part of the emulsion wells. There are also emulsion tubes under the main air jets.

In the middle part of the emulsion wells there is a hole with a large cross section. The latter is connected through special channels to the outlets on the atomizers. They are located in small diffusers.

How do dosing systems work?

On the K-151 carburetor, this works as follows. Due to the rarefaction in the region of the spray holes, the fuel rises through the main fuel jet through the emulsion well and enters the holes in the emulsion tubes. Then gasoline is picked up by air that has passed through the central tubes. This is how a fuel mixture is formed, which leaves through the side channels to the atomizers. This will then be mixed into the main airflow.

Additional devices in the carburetor

In addition to these basic elements, the carburetor also includes other mechanisms. Thus, the idle system is designed to maintainstable operation of the engine at speeds up to 1 thousand per minute. It consists of a bypass channel, adjusting screws, a fuel and air jet, an economizer valve.

The accelerator pump allows the car to move without failures and accelerate sharply if necessary. The system consists of valves in the main body, a ball valve, as well as a diaphragm mechanism and atomizer. According to the principle of operation, it resembles the operation of a gasoline pump.

Econostat is a device that allows you to enrich the air-fuel mixture at high engine speeds. Structurally, the element is additional channels through which, due to vacuum during open throttle valves, fuel enters the manifold.

Also in the design there are transitional systems. They are necessary for a smooth increase in speed at a time when the throttle valve of the second chamber has just begun to open. It is an air and fuel jet.

Carburetor malfunctions

During operation, various malfunctions can be observed. So, a common problem is high fuel consumption, black smoke from the exhaust pipe when you sharply press the gas pedal, unstable idle, poor dynamic performance, jerks and dips. In this case, the K-151 carburetor needs adjustment and repair.

Most often, poor-quality fuel can be identified among the causes of breakdowns. Because of this, jets, as well as air and fuel channels are clogged. In addition, due to high temperatures, the housingmay deform. During operation, the jets are subject to natural wear.

Most of the craftsmen, for whom the device and operation of the K-151 carburetor are familiar to the smallest detail, try to immediately change the jets during the repair process. It is believed that it is because of them that fuel consumption is growing, and the power unit can work unstably. But there is one nuance here. The jets, if worn out, are quite rare.

Adjustment

For those who are already familiar with the arrangement of similar units, it will not be difficult to service the K-151 carburetor. Its elements, disassembly and tuning in general are not much different from all other carburetors. To independently regulate the unit, it is enough to understand the principle and follow the instructions. There are several settings for this device.

Thus, idle speed, air damper, fuel level in the float chamber and throttle position can be adjusted. Only experienced craftsmen should change the fuel level, but any car owner can adjust the idle speed.

Step by step adjustment of the K-151 carburetor includes several steps. So, you need to warm up the engine to operating temperatures, then let it run at idle with the air damper open. Next, the quality and quantity screws are unscrewed and the engine is allowed to gain maximum speed. Then each screw is gradually tightened until there is no interruption in the operation of the engine.

With the help of the quantity screw increase the speed. In this case, you need to catch the position,when the engine is stable. It is desirable that this screw be tightened as much as possible. Don't forget that this bolt also affects fuel consumption.

Next, turn the quantity screw. This achieves stable operation of the engine at speeds in the range of 700-800 rpm. If the quantity screw is overtightened, then dips will begin when the gas is pressed sharply. It needs to be unscrewed back.

Conclusion

So, we found out what the K-151 series carburetor is. Now it can only be found on old Soviet cars and Gazelles of the 90s with a motor from the Volga ZMZ-402. The reviews of those who used it speak of the unreliability of the unit. The most successful are Solex and Weber. The owners say that the K-151 requires constant adjustment and tuning. In modern conditions, it is not suitable for operation.