Demon Fuel Systems 5563020GC - Manual (Page 10)

10
Metering Blocks
The metering block is the part of the carburetor having the two-fold job of controlling the flow of fuel
into the venturi along with the duty of mixing air and fuel prior to its introduction to the main air
stream. This is done through a series of sized orifices located in the metering block. These orifices
will be discussed from a tuning standpoint along with a discussion of the different metering blocks
available for the Demon carburetors.
Each block is specifically tuned for its specific application. The metering blocks from Demon
Carburetion are made of billet aluminum, compared with standard blocks that are cast zinc. This in
itself offers a major advantage.
Idle Feed Restrictor
The idle feed restrictor controls the amount of fuel that enters the idle circuit from the main well. This
orifice controls the amount of fuel available for the idle circuit. If all other tuning results in a lean or
rich idle circuit, an adjustment here may be necessary. As with any fuel restrictor, the larger the hole
in the restrictor, the more fuel that will be introduced into the idle circuit. Make small changes, .001" or
.002", to all four restrictors and work towards your desired tuning point.
CAUTION: The screw-in idle feed restrictors (Fig. 13) are sized from the factory. Modification is not
recommended.
Figure 13
Emulsion Bleeds
There are six (6) emulsion bleeds per metering block, three (3) for each main well. These orifices play
a part to control the density of the fuel in the block by metering the amount of air that is introduced
into the fuel in the main well. This, in conjunction with the air bleeds in the main body, help to control
the shape of the fuel curve. The emulsion circuitry of your Mighty Demon
™ has been engineered
through extensive wet flow, dyno and street & track testing. A note of caution: tuning of emulsion
bleeds should be done only by those with a deep knowledge of carburetors, otherwise, a poor running
engine or damaged internal engine parts could be the result.