What is Carburetor?- Definition, Types & How it works

The carburetor is called the “heart” of the car, and if the “heart” isn’t working properly, the engine can’t be expected to run properly, make enough horsepower, or run smoothly.

What is a carburetor?

A carburetor, also spelled as a carburettor, is a device for supplying fuel and air mixture to a spark-ignition engine. Carburetor components typically include a liquid fuel storage chamber, choke, idling (or slow-running) jet, main jet, venturi airflow restriction, and accelerator pump. 

The carburetor adds fuel to the air to create the right mixture for combustion in the cylinder. The cylinders of modern cars are fed more efficiently by the fuel injection system. This results in less fuel consumption and less pollution.

However, carburetors are still used in older automobile and motorcycle engines, as well as small engines in lawnmowers and chainsaws.

Gasoline engines are designed to take in just the right amount of air to burn the fuel properly, whether the engine is starting cold or hot at top speed.

Correct adjustment of the air-fuel mixture is the work of a clever mechanical device called a carburetor. It is a pipe that brings air and fuel into the engine through the valves, where they are mixed in different amounts for different driving conditions.

You might think “carburetor” is a rather strange word, but it comes from the verb ” carburet.”. It is a chemical term that means the condensation of a gas by combining it with carbon or hydrocarbon. So technically, a carburetor is a device that saturates air (gas) with fuel (hydrocarbon).

Who invented the carburetor?

The first carburetor was invented by Samuel Morley in 1826. The first person to patent a carburetor for use in a petroleum engine was Siegfried Marcus on July 6, 1872, who patented a device for mixing fuel and air.

A greatly simplified design of the original carburetor from Karl Benz’s 1888 patent. Fuel from the tank enters what is called a generator underneath, where it is evaporates.

Fuel vapors rise through the gray pipes, meet air coming down the same pipes, and enter the atmosphere through the upper holes. The mixture of air and fuel in the chamber enters the cylinder through the valve, where it is combusted to produce power.

Parts of Carburetor

Following are the Parts of the Carburetor:

  • Throttle Valve
  • Strainer
  • Venturi
  • Metering system
  • Idling system
  • Float Chamber
  • Mixing Chamber
  • Idle and Transfer port
  • Choke Valve
  • Throttle valve: A valve designed to regulate the supply of liquid as vapor or gas and air to an engine, automatically operated by handwheels, levers, or especially governors.
  • Strainer: It is a device used to filter the fuel before entering the floating chamber. It consists of a fine wire mesh that filters the fuel and removes dust and other airborne particles. If these particles are not removed, they can block the nozzle.
  • Venturi: Air passes through a narrow neck inside the carburetor called a venturi, where the flow rate increases. A slight vacuum is created inside the venturi as the faster air flow lowers the pressure. The fuel jet opens into the venturi and a slight vacuum pulls the fuel from the jet into the air stream.
  • Metering system: The fuel discharge nozzle is located inside the carburetor barrel with its open end at the narrowest part of the throat or venturi. This pressure difference or measuring force causes the fuel to come out of the discharge nozzle.
  • Idling system: Provides air/fuel mixture at speeds below 800 rpm or 20 mph. The throttle is mostly closed when the engine is idling. Air flow is restricted through the air horn to create sufficient vacuum in the venturi.
  • Float Chamber: The float chamber is a device to automatically adjust the flow of liquid to the system. This is mostly found in internal combustion engine carburetors that automatically meter fuel to the engine.
  • Mixing chamber: In the mixing chamber, air + fuel mixing took place. It is then fed to the engine cylinders.
  • Idle and transfer ports: In addition to the main nozzle in the venturi part of the carburetor, two other nozzles or ports supply fuel to the engine cylinders.
  • Choke valve: Sometimes a choke valve is installed in the carburetor of an internal combustion engine. Its purpose is to restrict air flow during engine start-up and thereby enrich the air-fuel mixture.
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How does a carburetor work?

A carburetor relies on the vacuum created by the engine to draw air and fuel into the cylinder. The throttle can be opened and closed to increase or decrease the amount of air entering the engine. This air moves through narrow openings called venturis. This creates the necessary vacuum to keep the engine running.

Carburetors vary greatly in design and complexity. The simplest one imaginable is basically a large vertical air pipe at the top of the engine cylinder and a horizontal fuel pipe attached to one side.

As air flows through the pipe, it must pass through a narrow bend in the middle. This increases speed and reduces pressure.

This twisted part is called venturi. As the air pressure decreases, it creates a suction effect that draws air in from the side fuel pipes.

When a fluid flows into a smaller space, its velocity increases but its pressure decreases. This could explain why the wind whistles between buildings and why canal boats moving parallel to each other often push against each other.

This is an example of the law of conservation of energy. If the pressure is not reduced, the fluid will gain more energy by flowing into the narrow space, which violates one of the most fundamental laws of physics.

here’s how Carburetor works:

  • Air flows from the car’s air intake to the top of the carburetor and passes through a filter to remove debris.
  • When the engine is first started, adjust the choke so that it almost blocks the top of the pipe, reducing the amount of air intake (increasing the fuel content of the mixture entering the cylinder).
  • In the middle of the tube, air passes through a narrow kink called a venturi. This increases speed and reduces pressure.
  • The drop in air pressure creates suction in the fuel pipe and absorbs the fuel.
  • A throttle valve is a valve that rotates to open or close a pipe. With the throttle open, more air and fuel enter the cylinders, making the engine produce more power and the car move faster.
  • The mixture of air and fuel flows into the cylinder.
  • Fuel is supplied from a small fuel tank called a floating feed chamber.
  • As the fuel level drops, the floats fall into the chamber and open the hatch at the top.
  • When the valve is opened, more fuel flows from the main gas tank to fill the chamber. This raises the float and closes the valve again.
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Types of Carburetor

There are three types of carburetors:

  • Up-draft carburetors
  • Horizontal type carburetors
  • Down-draft type carburetors

Up-draft type carburetors

An updraft carburetor is a type of engine component that mixes air and fuel, and the air enters the engine from the bottom and exits from the top.

Updraft carburetors were the first type of carburetor in common use. According to Edward Hebdo of Power Equipment Engine Technology, with a high-flow carburetor, air flows upward into the venturi. Other types are down draft and side draft carburetors. High flow carburetors may require a drip collector.

Down-draft Carburetors

This carburetor works with slower air velocities and larger passages. This is because gravity helps the air-fuel mixture flow into the cylinder.

A downdraft carburetor can deliver plenty of fuel when you need high power at high speeds.
In this type of carburetor, air comes from the top of the mixing chamber and fuel comes from the bottom of the mixing chamber. The same principle works here. The low pressure created by the two fuel venturis causes the fuel and air to mix in the tubes and here.

Horizontal carburetor

This carburetor is used when the assembly space is limited. Horizontal or side carburetors, as the name suggests, have the jet tubes arranged horizontally. Another advantage of this type of carburetor is the lack of a right-angle mechanism in the inlet, which reduces flow resistance.

The working principle of this type of carburetor is very simple. Now the carburetor remains horizontal and air enters from one end of the carburetor as shown in the image below. It is then mixed with fuel to form an air-fuel mixture that is sent to the engine cylinders for combustion.

Functions of carburetors:

The main functions of carburetors are:

  • The primary function of the carburetor is to mix air and gasoline to create a high combustion mixture.
  • Controls engine speed.
  • Also adjust the air to fuel ratio.
  • According to changes in engine speed and load, increase or decrease the amount of air-fuel mixture.
  • Always keep a fixed fuel tip in the float chamber.
  • It vaporizes the fuel and mixes it with air, turning it into a homogeneous mixture of air and fuel.
  • To provide the right amount of mixture with the right power at any load and engine speed conditions.
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Advantages of the carburetor:

  • Carburetor parts are not as expensive as fuel injectors.
  • With a carburetor you get more air and fuel mixture.
  • When it comes to road testing, the carburetor has better power and precision.
  • Carburetors are not limited by the amount of gas pumped from the fuel tank. This means the cylinder can pull more fuel through the carburetor, resulting in a richer mixture in the chamber and more power.

Disadvantages of carburetors:

  • At very low speeds, the mixture supplied by the carburetor is so lean that it does not ignite properly and requires a makeup in the carburetor to enrich in such conditions.
  • The work of the carburetor is affected by changes in atmospheric pressure.
  • A carburetor is heavier than a fuel injector, so it uses more fuel.
  • Air pollution is more than fuel injectors.
  • Carburetor maintenance costs are higher than fuel injection systems.

Applications of Carburetor:

  • Used in spark ignition engines.
  • It is used to control the speed of the car.
  • It converts the main fuel i.e. gasoline into tiny droplets that mix with air and burn smoothly and properly without any problems.


What is a carburetor?

A carburetor also spelled carburettor, is a device for supplying a spark-ignition engine with a mixture of fuel and air. Components of carburetors usually include a storage chamber for liquid fuel, a choke, an idling (or slow-running) jet, the main jet, a venturi-shaped air-flow restriction, and an accelerator pump.

What are the types of carburetors?

There are three types of carburetors according to the direction in which the mixture is supplied:

  • Up-draft carburetor.
  • Horizontal type carburetor.
  • Down-draft type carburetor.

What are the parts of a carburetor?

Parts of Carburetor:

  • Throttle Valve
  • Strainer
  • Venturi
  • Metering system
  • Idling system
  • Float Chamber
  • Mixing Chamber
  • Idle and Transfer port

How does a carburetor work?

A carburetor relies on the vacuum created by the engine to draw air and fuel into the cylinders. The throttle can open and close, allowing either more or less air to enter the engine. This air moves through a narrow opening called a venturi. This creates the vacuum required to keep the engine running.

How To Clean a Carburetor?

Directions for How to Clean a Carburetor:

  1. Dilute the cleaner
  2. Clear air filter
  3. Remove the carburetor
  4. Remove carburetor float
  5. Remove other removable components
  6. Soak and scrub components
  7. Rinse and dry
  8. Reassemble and replace

What does a carburetor do?

Carburetor, also spelled carburettor, device for supplying a spark-ignition engine with a mixture of fuel and air. Components of carburetors usually include a storage chamber for liquid fuel, a choke, an idling (or slow-running) jet, the main jet, a venturi-shaped air-flow restriction, and an accelerator pump.

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