Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

lots of problems

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crane_guy:
OK cliff id like to start over  I am confused and I could use some advice and clarification.
The carb is still the same 17057584.  I now have an Edelbrock mechanical pump and a Holley pressure regulator. I still have a few remaining problems. 
 Engine details
454 9:1 or could be as high as 9.75:1 compression, the cam is a comp cams ENERGY 4X4 X4 254H CAM, Camshaft, Hydraulic Flat Tappet, Advertised Duration 254/262, Lift .505/.505,
 if I understand things correctly my carb specs are as follows all measurements were taken by go and no go using # bits

idle tube:0465”
idle down channel: .043''
upper idle air bleed:.116''
lower idle air bleed: .076''
idle air bypass: blocked off
holes under idle mixture screws: .0995''
holes in throttle plate: .089''
jetting is 74 and 41k
this carb has an external adjustable apt screw

I do live in Calgary, Alberta at 3900 ft barometric pressure can be anywhere from 99 to 104 kpa

the tuck runs and starts great, but I believe I should have better performance, and throttle response that what I have. I ran the truck with 76 and 49 k rods but it was too rich. Right now with the 74/41k,I have a lean crackle on hard engine braking, but a much better throttle response and a cleaner sound at mid range. But it has a foul smelling exhaust on idle, smells lean and not rich. I can stall the motor when I close of the idle mixture screws.  Right now the mixture screws are at 4 ½ turns out.

Some questions
can the idle channel and idle tubes be drilled with out removing them ? Is the restriction the whole tube ? Or is it just the end ?
What length of bit do I need ?
What is the max size I can go on mixture screw hole ? That is the hole perpendicular to the mixture screw ?
The picture I have seen of main air bleeds have a brass insert in the hole, are mine missing ?
Do you think I should install un-drilled primary plates and re activate the idle by pass air.
Should I just find a new carb ?

Thanks

crane_guy:
here are some pics

Cliff Ruggles:
I see the problem, thanks for the pics.

You are working with a large main airbleed carburetor.  They are the most difficult to set-up.  I would suggest contacting us for a complete recalibration package, which includes new main airbleeds.  Those carburetors simply let in too much emulsion air to ever get a good clean fuel curve with them....Cliff

crane_guy:
ok well thats good news...i think whats involved with the recalibration kit ? from the pics what else do you suggest ? jetting, where do you think i should start ? how do i get order calibration kit ? what sort of lead time do you have for this ? what forms of payment do you have ?

Cliff Ruggles:
Open up the bypass air system in the main casting.

Install main airbleeds.

Install new jets, and metering rods.

I would also get one of our HP needle/seat assemblies, and the correct accellerator pump and springs.  Most of the time they put used pumps in them, with the wrong spring that coil binds before the pump completely compresses.

One of our fastener kits would also be a good idea, with black oxide coated screws and they are long enough to stake them on the shaft(s), etc.

Call the shop for parts, 8am-5pm M-F EST.....Cliff

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