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FUEL SYSTEM
The fuel system stores the fuel, delivers it to the carburetor, and mixes it with the proper amount of air to meet the varying speed and load conditions your car encounters. To accomplish these jobs, this system requires the following components: a storage tank, flexible and steel fuel lines, a pump, a filter, a carburetor, an air cleaner, and an intake manifold.
The fuel tank, the reservoir for the fuel system, is vented through either the charcoal canister or the gas cap. Most fuel tanks are de-signed with a pickup tube located just above the bottom of the tank, so that rust, dirt, or water which may collect at the bottom of the tank is not drawn into the fuel line, fuel pump, or carburetor.
The fuel lines are made up of steel tubing and neoprene sections. Usually the steel line runs along the chassis from the tank to the fuel pump and has flexible neoprene attachments to the fuel tank pickup at one end and to the fuel pump at the other. This arrangement allows for engine movement.
When the fuel system is in operation, the lines are subjected to both vacuum and pressure;vacuum from the tank to the pump and pressure from the pump to the carburetor. Over time, leaks in the form of air entering the system or fuel leaking out may result.
In most modern cars, the fuel pump is driven by the camshaft. The purpose of the pump is to draw the fuel from the tank and send it to the carburetor. In doing this, it must supply to the carburetor a constant quantity of fuel, at a prescribed pressure, to meet the engine's differing requirements. On some cars, certain Buick, Chevy, and Ford models, for example, there is an electrically-operated pump located in the fuel tank itself.
The carburetor is designed to mix the correct amount of fuel with air, by volume, to meet the full range of operating conditions from starting to full revolutions per minute (RPM). Gasoline is used as a fuel for the car engine because of its very high potential energy;three times that of dynamite. Composed of 15 percent hydrogen and 85 percent carbon, gasoline when mixed with air and atomized, forms a very highly combustible mixture capable of releasing huge amounts of heat energy.
In this chapter you will learn how to service and replace the fuel tank, fuel lines, the fuel pump, and the carburetor.
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