K151C (carburetor): adjustment, device and principle of operation

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

K151S is a carburetor designed and manufactured at the Pekar plant (the former Leningrad carburetor plant). This model is one of the modifications of the 151 carburetor line 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 (new generation carburetor) could work with engines such as ZMZ-24D, ZMZ-2401, UMZ-417 and many other units of a similar design.

This device is equipped with most modern systems and mechanisms designed to improve technical and operational, as well as environmental performance. Consider the design of the device, the principle of operation, methods of repair and adjustment.

Design

K151C - carburetor, which is equipped with two metering devices in the first and second fuel chambers. Also, this model is equipped with an idling system, semi-automaticstarting system, economizer. The design provides for an accelerating pump that sprays fuel into the first and second chambers. Along with other systems, there is an EPHX with a pneumatic drive and electronic control.

What is the feature of stepless semi-automatic start system? Thanks to her, you no longer need to press the gas pedal to start a cold engine.

The unit has two vertical air channels. At the bottom of them 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, one circuit first opens, and then another. This is a two-chamber carburetor. The circuit whose damper opens first is called the primary circuit. Accordingly, the secondary camera goes further.

In the middle part of the main channels for the passage of air, special cone-shaped narrowings are installed. These are diffusers. Due to them, a vacuum is formed. It is necessary that during the movement of air there is a suction of fuel from the float chamber of the carburetor. 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 does the K 151 carburetor work? K151C consists of three main parts. The top one is the case cover. It has a flange and studs, a device for ventilation of the float chamber, as well aslaunch system details.

The middle part is the body of the unit itself. Here is the float chamber, float mechanism, fuel supply systems. Throttle valves and their housings, an idle device are installed in the lower part.

Main dosing system

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

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

Holes are provided in the walls of the emulsion wells, which are connected to the outlet nozzles. Due to the rarefaction in the zone of the nozzle holes, the fuel rises through the emulsion wells. Then it goes to the holes in the tubes. Then the fuel is mixed with air in the central part of the tubes. After that, it leaves through the side channels to the atomizers. There, the fuel mixes with the main air.

Idling system

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

1. Bypass channel.
2. The screws used to adjust the K151C carburetor.
3. Fuel and air jets.
4. Economizer valve.

Accelerator pump

It allows the engine to run stably throughout the entire range, without dips when the accelerator pedal is pressed hard.

The pump consists of additional channels in the carburetor body, a ball valve, a membrane mechanism and an atomizer.

Econostat

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

Transition system

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

Optional equipment

That's what K151C is. The carburetor is additionally also equipped with a filter in the form of a protective mesh. Also, the unit has a return fuel channel. Through it, excess gasoline goes into the gas tank.

Differences between the K151C and the basic K151 carburetor

We looked at how the K151C carburetor works.

Its device, at first glance, is practically no different from the entire 151st series. However, there are still minor differences. So, the small diffuser has a more advanced design. The carburetor uses an accelerator pump sprayer for two chambers at once. The developers also changed the profile of the cams on the pump drive. The air damper drive is now stepless. This greatly simplifies cold start.engine. Also changed the settings of dosing systems. As a result, the environmental performance has been improved.

K151C - more efficient carburetor than K151. So, with it, the dynamics of the car improved by 7%. Up to 5% decreased fuel consumption when driving in the urban cycle. Starting the engine has improved significantly, and the engine idling has also stabilized.

How to connect the carburetor?

Old car owners often don't know how to connect this device. The K151C carburetor is connected as follows.

There are 2 hoses in the design. The main fuel pipe is connected to the fitting located under the float chamber, the one closest to the motor. The return fuel channel will be connected to the lower outlet. It can be seen on the opposite side of 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 economizer valve. This is the hose that comes from the solenoid valve. The second is connected to the lower fitting on the back of the throttle valves.

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

K151C carburetor: repair, adjustment

There are several kinds of adjustments. So, you can adjust the idle, the fuel level in the float chamber, the position of the throttle and air dampers.

The fuel level is changed whenhelp 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, the engine must be warmed up to its operating temperature. Next, open the throttle 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 increase the speed with the quantity bolt until the engine runs smoothly. The adjustment mechanism responsible for quality is screwed up to the stop. What do they do after that?

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

Conclusion

We looked at the 151C carburetor. Repair of the K151C carburetor and its adjustment, as you can see, can be done by hand. This is convenient if the breakdown happened far from the service station or at home. And even beginners will be able to service the carburetor.