Edelbrock 1405 Serries - Manual (Page 4)

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Edelbrock Performer Series Carburetor Owner’s Manual 8/94
METERING SYSTEMS
The Edelbrock carburetor has three (3) basic systems that meter fuel to the engine: The Idle System,
Primary Main System, and Secondary Main System. By understanding the operation of each you will
be better prepared to calibrate your carburetor.
Idle System: The Idle System delivers 100% of the idle fuel. It also meters fuel at off-idle throttle
positions; a large percentage at just off of idle decreasing to a minor influence as the throttle is
opened wider. The idle setting is critical both to a smooth idle at proper rpm and to a smooth
transition to part-throttle operation.
Idle System
Figure 2
Typical Engine A/F Ratios
Figure 1
(1) Main Jet and
Metering Rod
(2) Primary Well
(3) Idle Jet
(7) Transfer Slot
(8) Idle
Screw
Port
(4) 1st Idle Air Bleed
(5) Idle Channel Restrictor
(6) 2nd Idle Air-Bleed
Idle
X
Part-throttle cruise
Part-throttle acceleration
Wide open throttle
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Engine RPM
10.0
Lean
11.0
12.0
13.0
14.0
15.0
16.0
17.0
A
/
F
R
A
T
I
O
Rich
1403-1413 Perf Series Carburetor Owner's Manual.qxd 3/31/2006 12:04 PM Page 3