How Weber Carburetors Work

What Is a Weber Carburetor?

1. The Weber carburetor is made by the Weber Company, a well-known purveyor of automobile parts for many decades. While the construction of their carburetors is no different from any other brand, Weber carburetors are known for their excellent performance due to robust and hard-wearing qualities.

The Weber carburetor is a system designed to ensure that the correct mixture of fuel and air reach a vehicle's combustion cylinders for maximum power and performance. Because the optimum fuel mixture changes as the vehicle's RPM rises, the carburetor must be able to compensate for this, and therefore cannot be a static system.

Weber Carburetor Layout

1. Most Weber carburetors are dual barrel, that is, there are actually two carburetors sitting side-by-side to ensure that the engine performs well even if one of the carburetors should fail or become clogged. The basic layout of the Weber carburetor is a large air filter covering an intake set over the top of the engine. The air intake is a straight shot to the combustion cylinders, but set into the side of the intake's piping is a pinhole. This pinhole is the part where the air intake connects with the actual mechanics of the carburetor. It's known as a jet. The jet extends back away from the air intake to a metal block. 

The part of the block connecting to the jet is called the venturi. It narrows progressively from the block. Behind the venturi is the throttle plate, essentially a spring closed valve connected to the vehicle's throttle. Behind the throttle plate is the vehicle's fuel supply. In the case of a dual barrel carburetor, there would be two jets, two venturis, and two throttle plates.

How Does a Weber Carburetor Work?

1. A Weber Carburetor works by means of a vacuum. The constant flow of air from the intake passing by the jet creates a vacuum. When the throttle is engaged, and depending to what degree, the throttle plate opens up, allowing fuel to be pulled through the venturi and down the jet. Upon leaving the jet, the fuel is essentially atomized because of how small the jet's diameter is. It mixes with the air and is pulled along to the combustion cylinders in short order. The throttle controls how much fuel is allowed to pass through the throttle plate, thus controlling how fast the engine is allowed to work.