Bill-
The "idle circuit" is a mini-version of the
"main circuit" in terms of tuneability, without an emulsion tube.
For instance: 50F9
50 is the size of the fuel jet for the idle
circuit; F9 is the size of the opening of
the air corrector for the idle circuit.
As in the main circuit, the size fuel jet
controls mainly in the lower ranges, the
air corrector towards the top of the rpm
range as you tune "progression" from idle
to that rpm wherein fuel begins to issue
forth in the aux. venturi as the main system begins to "come in".
Tuning progression initially is a matter
of turning the idle screw to increase rpm
slowly after idle volume screws have been
set more or less according to book.
If it's smooth at the bottom and leans
or richens toward the top, change of air
corrector is required, one way or the other. When it's the "other way",
change
of fuel jet itself, is required.
Am not familiar with Braden Book though
I am sure it is fine and should explain
foregoing in great detail. If not, check
with local sports car parts supplier and
pick up the two Pasini booklets.
These, I know, are extremely detailed but,
once principles are absorbed by "user",
makes understanding and tuning more
logical by far.
Still, if both 40 and 45 giving you bog off
idle, suspect overadvanced condition first.
Capt. Bob
' 61:{)
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