Can the negative pressure switch of scooter fuel tank be removed and directly connected to carburetor?

You can't. Atmospheric pressure will spread from high pressure to low pressure. When the piston of a two-stroke engine is at the top dead center (or when the piston of a four-stroke engine is at the bottom dead center), a low pressure will be formed below the piston in the crankcase (above the piston of a four-stroke engine).

At the same time, this low pressure will also cause low pressure in the carburetor. Because the pressure outside the engine and carburetor is relatively high, air will rush into the carburetor and enter the engine until the pressure is balanced. The air flowing through the carburetor will drive the fuel, and then the fuel will mix with the air.

Extended data:

The carburetor is actually a pipe with an adjustable plate called a throttle plate in the middle to control the air flow through the pipe. There is a constriction called venturi in the pipe, where a vacuum is formed. The constricted portion has a metering hole from which fuel can be sucked by vacuum.

Motorcycle carburetor looks very complicated, but as long as you master some principles, you can adjust the motorcycle to the best condition. All carburetors work under the basic principle of atmospheric pressure. Atmospheric pressure is a powerful force that exerts pressure on everything. It will change slightly.

But there is usually a pressure of 15 pounds per square inch. This means that the atmospheric pressure is 0/5 pound per square inch/kloc. By changing the atmospheric pressure in the engine and carburetor, the pressure can be changed and fuel and air can flow through the carburetor.

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