Carburetor
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Under high-throttle conditions, some carburetors are equipped with a secondary circuit, which is essentially another set of jets (similar to the primary circuit) which allow even more fuel into the intake charge. | Under high-throttle conditions, some carburetors are equipped with a secondary circuit, which is essentially another set of jets (similar to the primary circuit) which allow even more fuel into the intake charge. | ||
| − | A transition circuit, often referred to as an "accelerator pump" squirts fuel into the rushing intake charge and is actuated by positive movement in the throttle. For example, when pressing the accelerator from 1/4 position to 3/4 position, the accelerator pump squirts an amount of fuel proportional to the amount of accelerator travel into the carburetor bore. This amount can be modified by accelerator pump cams as well as a number of other methods depending on the brand of carburetor. | + | A transition circuit, often referred to as an "accelerator pump" squirts fuel into the rushing intake charge and is actuated by positive movement in the throttle. For example, when pressing the accelerator from 1/4 position to 3/4 position, the accelerator pump squirts an amount of fuel proportional to the amount of accelerator travel into the carburetor bore. This amount can be modified by accelerator pump cams as well as a number of other methods depending on the brand of carburetor. The accelerator pump is also used to add fuel for initial starting in many cases (as when "pumping" the gas on a cold motor). |
Under cold coditions, a choke circuit can be used which increases the amount of fuel in the intake charge. This is a solution to the problem that gasoline does not atomize well when it is cold. This circuit is inactivated either manually or by an electronic actuator when the engine reaches operating temperature. | Under cold coditions, a choke circuit can be used which increases the amount of fuel in the intake charge. This is a solution to the problem that gasoline does not atomize well when it is cold. This circuit is inactivated either manually or by an electronic actuator when the engine reaches operating temperature. | ||
Carburetors can contain other circuits such as power valves (vacuum dependent). Again, the reason for every circuit that a carburetor has is to provide a mechanical fix for operational/environmental challenge. | Carburetors can contain other circuits such as power valves (vacuum dependent). Again, the reason for every circuit that a carburetor has is to provide a mechanical fix for operational/environmental challenge. | ||
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