Demon Fuel Systems 1563010VE - Manual (Page 14)

14
Power Valves
The power valve, located in the primary metering block between the two main jets, offers a boost in
available fuel to the engine in high load conditions without creating an over-rich idle or part throttle.
Power valves are marked with a vacuum rating. This rating is the point at which the valve will open.
The lower the number, the more the vacuum has to drop for the valve to open. When the engine is
under a big load, it produces decreased manifold vacuum along with an increased demand for fuel.
When the manifold vacuum is less than the rating on the power valve, it opens and allows extra fuel
to enter the main circuit of the metering block. It is a good idea to have a power valve rating that is
lower in number than the vacuum produced by the engine at idle.
Demon Inlet Fittings
Demon fuel bowls feature 9/16" x 24tpi threaded fuel inlets that accept the following fittings:
FITTING TYPE MANUFACTURER PART NUMBER
#8 FEMALE SWIVEL BG FUEL SYSTEMS 140024
#6 FEMALE SWIVEL BG FUEL SYSTEMS 140026
#6 STANDARD EARL’S 991942ERL
Main Body
The main body’s unique top shape increases the air flow capacity over standard carburetor designs.
The accelerator pump squirter and the air bleed bosses have been moved back to further improve
flow characteristics. These changes have an effect on the overall performance of the carburetor.
Figure 20
Air Bleeds
The air bleeds, located in the upper portion of the main body between the wall and the venturii, shape
the fuel curve by helping to control when the idle and main circuits start. The four (4) idle bleeds are
located closest to the air cleaner ring, while the four (4) high speed bleeds are found on either side of
the squirter bosses. A larger bleed can be used to slow down, or delay, the related circuit, and vice-
versa for a smaller bleed. As with the emulsion bleeds, tuning with the air bleeds should be done only
by someone with a deep understanding of carburetion to prevent a poorly operating carburetor.