Previous Toc Next    A fuel inlet needle valve clip connects the
inlet needle firmly to the float tab. This prevents sticking of
the fuel inlet needle due to gum deposits or impurities
sometimes found in the fuel.     In the idle range the air flow
through the carburetor is too small to cause a great enough
pressure drop in the venturi to operate the main metering
system. However, the high manifold vacuum in this speed range
provides a pressure difference sufficient to operate the idle
system.  The atmospheric pressure in the float chamber forces
fuelthrough the main metering jetinto the main well in response
to the manifold vacuum at the idle discharge hole below the
throttle plate. Fuel then passes into the idle tube through the
calibrated restriction in the idle tube tip which meters the
flow of fuel into the idle system. Air is introduced into the
idle fuel by the idle air bleed as the fuel passes out of the
idle tube and into the vertical idle passage. The fuel-air
mixture then travels down the idle pass