Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Need Tuning after dyno run

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leeklm:
Since it felt like I was chasing my tail around somewhat, I decided to start from scratch with tuning.  I wired the secondaries shut, and did some testing with primary jets, pump rod position, and apt settings.  Once everything was feeling good on full & part throttle, and looked good on the A/F readout, I am still a little boggy on the rolling start.  The new setup performs better with pump rod in outer hole, plus I downsized from a 73 to a 72 jet.  The A/F is reading around 10.2 during my boggy start, which seems too rich.  My idle is reading at 13.5 with 18" of vacuum. 

Based on the above notes, would it make sense to try to lean the accel pump?

Thank you!

Cliff Ruggles:
Full throttle start?.....Cliff

leeklm:
Correct, full throttle start

leeklm:
Found a nice remote parking lot for a little more testing today...

Regardless if I mash the throttle or just give it an instant 1/2 throttle from an off-idle 700 rpm rolling start, I still have the bogging for a few yards.  I tried from a faster rolling start, say around 1,200-1,500 rpm, and no problems at all.  The engine winds right up, breaks the tires loose when the TQ peaks around 3,500 rpm.

It feels so close to having the carb almost perfect, but am looking for that "instant on" switch when I punch the throttle... To recap, this is with a 2.20 1st gear, 3.31 posi rear, and 255/60/15.

Cliff Ruggles:
If it's acting up from a dead stop try installing factory baffle plate behind the choke housing, or filling the "slot" behind the choke housing with Marine Tex.  If  you can't tune out the stumble, it may be throwing some fuel out of the carb on hard launches....Cliff

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