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Claps in the carburetor: possible causes and solutions

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Claps in the carburetor: possible causes and solutions
Claps in the carburetor: possible causes and solutions

A lot of emotions, a lot of nerves and sleepless nights give car owners situations when the carburetor makes loud sounds or pops that are somewhat similar to shots. At the same time, the car jerks strongly, the engine is unstable. There are several main reasons that can provoke pops in the carburetor. Let's look at some of them below and find out how to solve the problems.

How does the malfunction manifest itself in general?

Such a malfunction is most often manifested under certain circumstances. Especially often shoots after engine repairs. Also, a malfunction may manifest itself after an accident. Often this is faced by those who actively tune the carburetor and engine. Popping in the carburetor is very typical for cars with high mileage.

shooting at the car's carburetor

Cotton can be heard when the accelerator is pressed sharply, after long periods of parking, on a cold engine, during loads in motion, and alsowhen trying to start the power unit.

Depending on what caused the shots, they can appear suddenly or they can manifest themselves gradually, with each day the intensity can only increase. Using a car with such a malfunction, in addition to inconvenience, may lead to the need for a major overhaul of the motor.

HV wires

One of the reasons why it shoots at a car's carburetor is the high voltage wires. When any repair work was carried out in the ignition system, car owners could, through inattention, incorrectly connect the wires to the ignition distributor. The spark will jump not in the compression stroke, but at another moment. This will provoke pops. Even if the engine suddenly starts, which is unlikely, there will not be enough power for normal movement.

why shoots at the car carburetor reasons

To diagnose such a malfunction, you need to make sure that the wires to the distributor are connected in the correct order. You should count from the mark on the distributor caps. As for the connection order, it is different for different cars.

Fuel composition

Another reason for pops in the VAZ-2109 carburetor or other auto-fuel mixture. She can be very poor or, conversely, too rich. Both in the first and in the second case shots are possible. The situation usually arises if any manipulations were carried out with the carburetor - for example, adjusting the mixture. If the fuel mixture quality screw is not set correctly, the wrong mixture will be prepared, which will burn outineffective.

Poor mix

If the engine runs too lean, then the portion burns out more slowly than a normal stoichiometric mixture. When the intake valve begins to open, the fuel in the cylinder will still burn out, and this will ignite a new portion of the combustible mixture. Since the afterburning of the mixture occurs in the intake manifold, then the driver will hear pops in the carburetor. Besides being very annoying, it can also cause the engine to overheat.

Rich Blend

When the engine is running on a rich fuel mixture, a coat of black soot appears on the electrodes of the candles. If there is a lot of carbon deposits, then, under the condition of high temperatures, it can cause ignition of a portion of the mixture at the wrong time. This will also result in pops and shots as the intake valve will still be open at this time. The malfunction manifests itself only on a hot engine. Gradually, the engine will sneeze more and more often. But the power will practically not fall - this can be observed in very rare cases.


You can diagnose the condition of the engine and the operation of the fuel system by candles. If the center electrode of the spark plug is white, then this indicates that the engine is running on a lean mixture. If the soot is black and dry, then this indicates a rich mixture.

car carburetor

To fix this problem, it is recommended to tune the carburetor. It is better to use a gas analyzer, since the setting, which relies on the human senses, does not always givedesired result. In addition, you need to choose a gas station before you buy fuel - sometimes black deposits can form due to the quality of gasoline.

Engine ignition timing

Claps in the carburetor of an UAZ or other vehicle can also cause an incorrectly set ignition timing. If the timing is too late, then the fuel mixture burns during the entire stroke of the piston stroke. When the inlet valve opens, the already burning old mixture will set fire to a new portion. The engine will warm up significantly. It is easy to diagnose - with late ignition, shots will be fired not only into the carburetor, but also into the muffler of the car.

You need to check if the initial ignition timing is set correctly. If in doubt, it is better to set the correct UOZ using a strobe light or directly on the road. Another indication that the ignition is late will be the white electrodes of the spark plugs.

If the ignition timing is too early, then the fuel mixture will ignite at the wrong time. Before the intake valves have fully closed, the mixture will ignite inside the intake manifold, causing the carburetor to pop.

Specialists recommend paying special attention to the ignition timing if any repairs have been made to the ignition system. In addition, engine knocking may occur when trying to depress the accelerator pedal hard.


This assembly is also capable of causing untimely and incorrect ignition of the fuel mixture in the engine cylinders. Among the distributor malfunctionsignition, you can highlight the breakdown of the cover, the breakdown of the slider, the oxidation of the contacts of the BB wires.

To determine whether the distributor is the cause of pops in the VAZ carburetor, a known-good assembly is installed. If the backache is gone, then you need to diagnose the distributor and troubleshoot it. This is the only way to get rid of pops.


Often, if the switch fails, it is basically impossible to start the engine. But this is just a theory. In practice, the switch can fail "half". Then the shots will be when trying to start the engine and during its operation. To correctly diagnose the causes of pops in the carburetor, you will need a new switch. If the motor stops firing after installation, then you need to change the switch.

why in car carburetor reasons

Often, the failure of this element in the early stages is almost imperceptible. The motor loses its stability, the speed fluctuates. But this is associated with the failure of candles. If you sharply press the gas, and the switch is out of order, then acceleration will be with failures. In this case, the carburetor will shoot a little.


Pops in the carburetor on the GAZelle will be heard from under the hood if the valve timing is off. Typically the belt drive jumps one to two or more teeth. In the first case, the motor will work normally, but power will drop significantly. If the phase shift was more significant, then you can bend the valves.

Among the reasons for the phase shift, one can single out inattention when setting the phases, replacing the belt,low tension, accident, wear of timing parts.

Such a malfunction must be diagnosed. To do this, check the installation marks on which the phases are set - they are on the crankshaft pulley and on the engine block. What you need to do to fix this malfunction depends on how far the phases have shifted and what the consequences of this.

Sometimes it is enough just to slightly adjust the operation of the gas distribution mechanism. But more often you have to disassemble the entire assembly.

If the phases have shifted, do not start the engine and try to drive it somewhere. Start the engine only after carefully checking the placement of the marks and eliminating the causes that caused the shift.

Inlet valves

If the valve is deformed or there are through burns on it, then the combustion chamber cannot be properly hermetically separated from the carburetor. If the plate is not tightly pressed against the seat, then the gases will break through into the manifold. Sometimes a fresh mixture ignites, which is accompanied by pops in the carburetor when you press the gas. This may even cause flames to escape from the carburetor.

To correctly diagnose a malfunction, experts recommend checking the engine compression. If during the checks a cylinder is found, for which there are suspicions of a lack of tightness, then a little oil is poured into it. This will eliminate intensive wear of the parts of the cylinder-piston group and the occurrence of rings. Combustion chambers with burnt or bent valves will show the same compression regardless of whether the oil was filledor not.

To repair and eliminate such a nuisance, you need to remove the cylinder head and change the valve with all related measures. If the valve is deformed, then it is also worth checking the timing phases. If the valve is burnt out, and the engine mileage is low, then it is worth looking for the causes of burnout.

If the engine is equipped with hydraulic lifters, it will not be superfluous to check how they work. If the hydraulic compensator is stuck, then this will lead to the same consequences as a burnt valve. In this case, claps may not be constant, but under certain conditions. Owners often complain about shooting at startup.

Heat gaps

Among the causes of broken thermal gaps are motor repairs, as well as untimely maintenance.

why is it shooting at the car's carburetor

During the repair, the distance between the pusher and the cam was accidentally or deliberately reduced. At the same time, before the repair work, the car started without extraneous sounds.

If the gaps were not adjusted in time, the surfaces shrink, wear out, and deform. If you do not adjust the thermal gaps in time, then shots at the carburetor are inevitable.

why shoots at the car reasons

In the first version, shots can be heard during trial runs after repairs have been made. In the second option, the breakdown manifests itself gradually. Initially, pops in the carburetor with a sharp pressure on the accelerator appear rarely and for a short time. Then, time after time, the duration of the claps increases.

Todiagnose incorrect thermal gaps, they must be checked using probes. If the car has been driving at the wrong gaps for a long time, then nothing terrible will happen. If the car has been used for a long time, then the edges of the valve plates are burned - in this case, repair is indispensable. Fire will enter the intake manifold even if the valves are adjusted correctly.

Shooting the carburetor on gas

Claps in the carburetor on gas are most often associated with an excessively lean mixture. Due to the large distance between the intake manifold and the gearbox, the gas does not have time to get to the cylinders. The result is a lean mixture.

Another reason for a lean mixture is an elementary air leak. There can be quite a few reasons for this. It can be a breather, and a poorly tuned air supply. Also, experts are sure that the problem may be a clogged gas filter.

why shoots at the carburetor reasons

It is not uncommon for gas firing to be caused by a twisted adjusting screw. It would seem that fuel economy. But on the other hand, the mixture is poor, and at the moment of a sharp increase in speed, the reduced supply of the gas-air mixture causes pops.


As you can see, there are many reasons for pops in the muffler, carburetor. But not all of them happen often. Usually the whole shooting is related to the ignition and the quality of the mixture. These are the most common reasons. You can fix such malfunctions with your own hands. And after the repair, the car will start normally again and work stably underany engine speed and load. In some cases, you will need the help of a specialist.

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