What is A Float System in Carburetor?

The float system in the carburetor has more systems than a carburetor. The float system keeps the fuel pump from forcing too much gasoline into the carburetor bowl. The float system detects the liquid in the carburetor fuel chamber. 
In this article, I will discuss the float system in a vehicle-

Float system in carburetor-


Float System in Carburetor

The float system consists of a float chamber or bowl, a float, and a needle valve arrangement. The float is a closed air-tight vessel, pivoted to the float chamber by a lever. The lever is attached to the needle valve, which sits on the valve seat through which the fuel comes into the float chamber. The level of the fuel in the float chamber can be changed by bending the lever lip so that it will seat the needle valve at different positions of the float.

The float and the needle valve operate to maintain a constant level of fuel in the float chamber. If the level of the fuel in the float chamber is too high, then too much fuel will feed from the fuel nozzle making the mixture rich. If the level is too low, then too little fuel will feed making the mixture lean. Both cases will cause poor engine performance. When the fuel enters the float chamber faster than it is withdrawn, the fuel level rises. This causes the float to move up, pushing the needle valve into the valve seat, thus closing the fuel inlet —no fuel can enter the float chamber. Then, if the fuel level drops, the float moves down drawing the needle valve from the valve seat, thus opening the fuel inlet-now fuel enters the float chamber. The float tends to hold the needle valve partly closed so that the incoming fuel just balances the fuel being withdrawn.


The float system in a carburetor is important to indicate the fuel level in the vehicle. But the tilting and overspeeding of the vehicle can change the level of the fuel due to the movement of the fuel. This is basically a mechanical system in a car.


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