10:1 compression, Lunati 60303, alum heads, stock manifolds, auto, new 71 repro carbs (6.5PV, #65 jets, #35 squirter, with blue cam), 18deg base timing, 14in vacuum @ idle. Engine starts and idles fine, though rich as center partially on the idle transition circuit. Idle originally 12.8 on AF meter. Widened the outboard plate holes 2 drill# sizes, from .082 to .089, which improved AF to 13.5, still a bit rich. Still debating whether to drill center plate or continue drilling outboards or ???

Noticeable hesitation when revving from idle in park (car not on the road yet).

Thots?

Your going down the wrong path, remove the front and back carbs and rest the idle mixture screws in the bases of them so ther both set at 1/4 to 1/2 turn out from bnottomed out, DON'T screw them in to tight Put them back on and readjust the center carb as needed, first thing is back the idle speed screw down so the throttle blades on the center carb so they are almost closed completely Let us know how that works BTW,once you get them to idle get ready to work on the outboard vacume pod springs Six paks are fun, huh You can do this

The outboards are set at 1/4 out. If I remove the center to set the idle slot "square" the engine won't idle. Been there done that.

hi
i did not get good idle till i had outboards 1 turn out ?

also would help hesitation prob at this setting , and may allow turning in center carb screws ?

what is vac in gear warm ?

fuel bowel screws center carb not snug enuf can cause too rich idle !

still not working drill center carb start at .080 .

also had a bad <week>resistor cause this condition !

You CAN'T adjust the outboards until you have a load on them...meaning until you DRIVE it.
A few things, I found that setting the floats a hair low is better than on the money, You can adjust your idle w/o the outboards hooked up...once you hook them up make sure they open 100% if not adjust the rods, I'd start by turning the screws all the way in and them back out 1.25...
You have much less cam than I do and I didn't have to drill squat. Start it up tunr the idle up to 2200 and let it warm up. set your timing to 36-38* full (vac adv unhooked) turn it back down to 900rpm, set for best idle vaccuum.
Go for a drive, now you can figure your PV/spring settings. What does the vaccuum drop to in gear? That will help w/ your PV selection...how fast do your outboards open? Now you have an idea about springs. I'm running the purples w/ 4.5PV and 35 Squirter.

Setting floats a hair low...just below the sight hole instead of right at it? Float levels are current dribbling on outboards, level with sight hole on center. Stock (new) fuel pump working OK, approx 6psi.

The "back out 1.25" apply to the outboards or center?

The 14in vacuum at idle is in gear; approx 15" in park. I welded the slot in the dizzy to get approx 38deg all in. Using points now, plan to eventually go with pertronix.

Don't know enough about carb design to determine if the hesitation and rich idle are related. I've tried different jets, little effect on the rich idle. Verified PV is working and should be OK for my vac levels. Rechecked accelerator pump lever clearance.

This can get pretty frustrating. I'd like to solve this without drilling if possible. Thx for

Yes the screws are the primary... and yes set the floats a hair lower than you would w/ a 4bbl. I haven't even touched my outboard screws ever... maybe I should...lol
What is your idle rpm? I have to have mine at 900-1000 but I have a solid roller...

The six pack is not the greatest place to begin your carb tuning experiance. Also, stabbing the throttle in neutral is not the best way to determine the status of the tune. Why don't you take it for a ride? What is your neutral and in gear idle rpm?

Based on what you've said and reading probably a little more into it, these are my recommendations for starters:

1) Make sure you don't have a vacuum leak.
2) Set the floats as they are designed to be set, at the bottom of the sight hole.
3)Adjust the outboard carb idle mixture screws to 3/4 turn out.
4)Make sure your center carb squirter squirts fuel at the first movement of the throttle.

Try these and report back.

Not saying this is the rightway to do it, but when I set mine up for the 1st time it was on a 11:1 440 w/ a 528 solid cam lashed tight. I checked the floats before I installed the car..how? I flipped them upside down...hahah I primed the center carb only, left the out boad rods unhooked, turned the mixture screws all the way in then back out 1.25 turns...I set my full timing then initail and finally tuned for best vaccuum at 800rpm. Then I hooked up the outboards. I checked the floats, they were a tad low but not enough to worry about. I shut the car off, then I had my son floor the car and I opened the ooutboards by hand to make sure I had 100% throttle. Worked fine.
Usually when holley carbs "dribble" as you state the floats are high. That or you need to adjust your outboard rods. With your cam your outboards should be shut, you shouldn't need to drill the holes any bigger. My cam has a duration of 292/297 (254/260@.050) and I didn't need to open mine up.
I think you are close, you just need to fine tune it.

you said in one post that you rechecked the accelerator pump clearance?
This is where i would look again there is a lot of misleading info on how to properly adjust the accelerator pump lever adjustment out there.
By reading and listening to what you are saying is the motor is hesitating when you quickly open the throttle Right?
Ok that is most often due to insufficient amount of accelerator pump shot or not quick enough shot .
Does the accelerator pump squirt like popping a zit or does it dribble when you barely move the throttle lever?
I have had this problem before on many holley's because people read the Holley tune ing books and always try and adjust the lever to have .015 clearance between the pump lever and the spring bolt at WOT
This is where i think the problem comes from .
The way i adjust the pump is like this i take the cam off and see
how well the pump squirts with me moving the lever with my finger also i watch very closely how far up the lever returns when the pump is at rest.
Then i make the spring bolt adjustment so the bolt is very short.
then install the cam in the original factory position.
Now the lever and pump arm should be very loose and this is where you need to be to start.
Now slowly and very carefully start to lengthen the bolt adjustment
so it just barely touched the pump lever at it resting position! This is the most important part! the adjustment should be so that the pump is getting full stroke!
You do not know how many holley's i have fixed with this simple adjustment if the pump is getting full stroke i bet your problem will go away .
Cj

Lots of good info here.
A couple things to add, hopefully not get you sidetracked.
These were set up with an idle solenoid to allow 1000-1100 RPM at idle, then shut it down with the key off to prevent dieselling. A bigger cam will only make the idle harder. It can be done, but it's a balancing act.
Are you getting any vacuum to the dist. at idle?
With a lot of initial advance as mentioned, any additional timing that gets pulled out will cause a stumble. Try to adjust without vacuum advance, then try it with...

Good Luck!

Lotsa good input here - THX ALL!!!!!!!!!!!

I didn't really notice the hesitation when I did the break-in on a test stand - which may suggest the problem to be a linkage matter. Either way I've got some good input here to check.

The other problem, the rich idle - getting to "square" on the idle transition slot with sufficient idle rpm - is haunting me. Need more air or less fuel, sounds simply huh? Holley tech suggested to drill the butterflies. I'm leaving that as a last resort.

Been doing/fooling with 6pk carbs a long time,never saw a set of end carbs that needed drilling beyond what they were.