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Solex Carburetor: Parts, Types & Working Principle with Diagram

In this post, we will discuss what is Solex Carburetor and How it works? Its Diagrams, Parts, Types, Working principles, and more.

What is a Solex Carburetor?

Solex is a French manufacturer of carburetors and the powered bicycle VéloSoleX. This carburetor is used in many European automobile industries. Such big industries as Rolls-Royce, Volkswagen, and Mercedes Benz.

Solex carburetors are invented by Marcel Mennesson and Maurice Goudard founder of Solex company. Solex carburetors are widely used by many European makers and are also used in passenger cars and commercial vehicles.

Solex Carburettor

As we already know the function of a carburetor:

  1. It combines air and fuel creating a highly combustible mixture,
  2. Carburetors regulate the ratio of air and fuel, and
  3. Carburetors control the engine’s speed.

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Parts of Solex Carburetor

Solex carburetor is a down draught type carburetor. It consists of the devices for starting, idling normal running, and acceleration. These are described in brief as follows.

Parts of Solex Carburetor

The figure shows a starting device for the Solex carburetor. It consists of a starter valve in the form of a flat disc having holes of different sizes.

These holes connect the starter jet and petrol jet sides to the passage which opens into the air horn below the throttle valve. The starter lever is operated by the driver from the dashboard, which adjusts the position of the starter valve so that either bigger or smaller holes come opposite the passage.

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Some Solex Carburetors

Examples of Solex Carburetor

Working of a Solex Carburetor

At the time of starting, bigger holes connect the passage so that more fuel may go to the engine. The throttle valve is closed, and the whole engine suction is applied to starting passage 1.

The petrol from the float chamber passes through the starter petrol jet and rises into passage 2, it comes out and mixes with the air entering through the air jet. This air-fuel mixture is rich enough for starting the engine.

After the engine has started, the starter lever is taken to the 2nd position. So that smaller holes connect the passage reducing the amount of petrol. In this position, the throttle valve is also partly open so that the petrol is also coming from the main jet.

The reduced mixture supply from the starter system in this situation is however sufficient to keep the engine running. When the engine reaches the normal temperature, the starter is taken to the “off” position.

Read also: What is Carburetor and Types of Carburetor [Complete Guide]

Types of Solex Carburetors

Solex carburetors are classified into three main categories by their type, the bore of the throttle chamber and by its model.

Solex carburetors are classified according to their direction of flow through the carburetor:

  1. Updraught Carburetors
  2. Horizontal Carburetors
  3. Downdraught Carburetors

These types of carburetors are classified according to the layout of the induction system:

  1. Simple Carburetor for single induction manifold
  2. Dal port Carburetor for two induction manifold
  3. Dual-port compound Carburetor for single induction manifold

Selection of Solex Carburetor

The Direction of Air Flow

If you want to replace an old carburetor with a new it is easily done by determining the flange type of carburetor. In modern vehicles, downdraught carburetors are commonly used, because it is readily accessible from all sides.

In sports cars and racing cars, the horizontal carburetor is used. Updraught carburetors are used for engines where the fuel is gravity-fed.

The Number of Carburetors

Usually, it is determined by the type of engine, whether one or more carburetors are used. Generally, in sports cars and racing cars, more than one carburetor is used.

The purpose of using multiple carburetors is to reduce the length of the induction manifold. And most importantly to reduce the bends which obstruct the free passage of the air-fuel mixture.

Advantages of Solex Carburetor

The following are the advantages of the Solex carburetor:

  1. The Solex carburetor’s primary benefit is its simplicity of starting.
  2. It delivers excellent performance and is reliable.
  3. Carbon production and waste are reduced by the Solex carburetor.
  4. It has a much higher throttle responsiveness than typical carburetors.


So now, we hope that we have cleared all your doubts about Solex Carburetor. If you have still any doubts about the “Solex Carburetor” you can contact us or ask in the comments. That’s it thanks for reading. If you like our article then please share it with your friends.

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About Saif M

Saif M. is a Mechanical Engineer by profession. He completed his engineering studies in 2014 and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at www.theengineerspost.com

3 thoughts on “Solex Carburetor: Parts, Types & Working Principle with Diagram”

    • The main materials used to make cars and their parts are steel, aluminum, magnesium, copper, plastics, composites, rubber, glass, fabric/leather, etc.

    • The materials used to make cars and their parts are steel, aluminum, magnesium, copper, plastics, composites, rubber, glass, fabric/leather, etc.


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