Carter AFB 4706s

[rgalajda]

I believe this is an original Carter 750 Comp series Afb ( before Federal Mogul bought them ). I picked this up the other day in good condition and am trying to figure out the idle circuit passages/bleeds. Below is a picture that I marked my measurements on . Don't understand what you guys ( Tuner ) refer to as 1st and 2nd air bleeds? Would appreciate any help I could get.

[GTO Geoff]

The idle cct has two air bleeds. As shown in the photo [1] MAB 0.033 [2] By pass air 047.
The Economiser 056 feeds air + fuel to the idle cct & transfer slot.
The idle tube 032 is the idle fuel jet.

[rgalajda]

Thanks for the reply Geoff
Tuner wrote.
"The idle quality improvement is likely because the Carter AFB design incorporates an Idle Channel Restrictor between the 1st and 2nd idle air bleeds. The Carter patent covering this idle circuit feature used the nomenclature “Economizer” for this channel restrictor orifice between two idle air bleeds.

The fuel from the IJ is mixed with air from the 1st IAB before passing through the ICR. The addition of air makes the mixture of A/F compressible, and so it obeys the behavior of compressible flow which is limited to the speed of sound and is throttled significantly above about .5 Mach.

The mixture of air and fuel passing through the restrictor reaches very high velocity and so is subjected to shock and high turbulence which effectively increase vaporization of the liquid fuel. "

I believe I have his now. Fuel travels thru the Idle Jet ( the smaller tube pressed into the bottom of the cluster) up to the 1st idle air bleed, ( brass restrictor in the side of the cluster) from here it travels across thru the channel restrictor (Economizer) to the 2nd idle air bleed (top of the cluster) and down the cluster to the idle passage and to the idle port.
The 1st idle air bleed (brass) is larger than the idle channel restrictor(economizer) That is where I measured wrong.
The tube pressed in to the top of the cluster is the Main Air Bleed for the Primary circuit.