Thermoquad tuning on 318
Accelerator pump has a pretty strong shot, and I set the float level to spec before installing the carb
I know that TQ pumps do pretty good, but I'm not talking about hammering it.
Your carb has multiple tip-in problems, which at your vacuum level, should not exist. Your low speed system is too slow to get moving. The A-pump is usually slower yet when tickling the throttle.
Really, the problem boils down to the AFR dipping lean at Tip-in, so that means, as explained initially, the fuel is lagging.
So then, it could just be a low wet fuel level, or air getting into the idle well that was not designed to be there.
In addition to what I said in a previous post, I will now add this.
If your intake-plenum is getting air anywhere other than past the primarys plus a trickle from the PCV valve, then, to keep the rpm down, you will close the throttle with the speed screw. This has the unhappy result that the transfers also shut off. In response to the rough idle that then occurs, you will open the mixture screws, and then it idles just fine.
But when you step on the pedal, the transfers lag, the AFR goes lean, and you feel it as a hesitation.
But you say, the vacuum is 21 inches.
To which I say, yeah so? All that means is that your throttles are very closed. Reinforcing my point.
I am NOT suggesting that your intake is sucking air.
I'm suggesting that If the WET fuel level is correct, then, either the transfers are stalled, or unregulated air is getting into the intake from a more local; source; such as
> the secondary throttle valve is not shut tight, or
> the base gasket is not sealing, or
> the PCV is flowing too hard, or
> a throttle shaft is really baggy, or
> the booster is sucking air, or any other accessory is, or
and so on
BTW
stale gas will do a similar thing because all the light weight molecules have evaporated. This leaves only the heavier molecules behind which are not particularly eager to burn. Your gas must be clear. Faintly yellow can already be troublesome.
And finally, too much Idle-advance while making the low rpm snappy, has a side effect.
The extra advance increases the idle-power, which increases the idle rpm. In response, you will crank the speed screw out, which then reduces the fuel coming from the transfers, and there we are again chasing our tails.
NOT ALL carbs are able to deal with extra advance.
BTW; your metering rods do little to nothing to eliminate tip-in sag. Tip-in sag is strictly an Idle synchronization issue between; the transfers, the mixture screws, and the wet fuel level.
A bog after tip-in, or more like a flat spot, as the rpm increases under light acceleration, now that would be Power-circuit issue which does involve the Metering rods and specifically how far out of the M/Js the mechanical lifter has lifted the tree.
To solve a primary bog under more spirited roll-ons, with 21 inches of vacuum, yur probably gonna need a different metering-rod spring.