Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
66 Buick Q-Jet
Rhett:
I've got a 66 Q-jet, and I am trying to dial out an off-idle stumble. I've got the the specs as such...when it was cooler it was almost gone, but now it seems to have gotten worse since the summer heat. It doesnt load plugs or soot the pipes, but could I now be too rich at that throttle range?? The pump shot is good and I had to go big on the ICR to get it as good as it was in the spring. Any suggestions?
Thanks, Rhett
Fuel Inlet 0.145
Float Level 0.250
Idle Tube 0.035
Idle Channel Restriction 0.060
Accel Pump Discharge 0.030
Main Air Bleed (upper) 0.070
Main Air Bleed (lower) 0.070
Idle Air Bleed (upper) 0.052
Idle Air Bleed (lower) 0.070
Mixture Hole 0.094
Primary Jets 0.074
Primary Rods 0.044
Secondary Well restriction 0.032
Secondary POE Restriction 0.052
Secondary Tube Restriction 0.036
Secondary Rods CK .0527 L
Secondary Valve Opening 1.130
Secondary Hanger M
Cliff Ruggles:
I'd reduce the idle down channel restrictions, you have enough idle fuel for a "Pro Stock" engine!.....Cliff
Rhett:
Agreed, although it doesnt load up at idle..so at least I've got that!
How can I increase the off idle fuel to get by the stumble? lengthen the slot? Open it up?
Opening the ICR worked to a point, and rods/jets messed with part throttle performance..
Is there anyting else that can be messed with?
Cliff Ruggles:
Might want to stagger the jet/rod relationship a bit to bring in more fuel at cruise, which will offset how much fuel is needed from the idle system to get thru transition. 74 jets are plenty rich in that carb, might want to reduce the jet size a few numbers and go smaller on the metering rods by 31 or 32 numbers.....Cliff
Rhett:
So something like .071 Jets and .039 rods?
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