I've gotten my 63 Hawk road worthy after too many years of sitting in the garage. During the process I rebuilt the Carter AFB carburetor (3540S). Now I'm just fine tuning things for best performance. The plugs were black, so I changed metering rods to lean the mixture. I'm running .093 main jets and metering rods with .075 idle step and .047 secondary step. (I'm in Colorado about 5200' altitude) Starts and runs GREAT no smoke at idle and but a bit when revved up. Problem is mixture screws have very little effect. Idle speed increases and idles best with screws all the way in. No vacuum leaks that I can find. Sprayed carb cleaner around base of carb and intake manifold. Has 16" of vacuum at idle from the power brake vacuum source on the intake manifold, yet only 10" at the hose going to the vacuum advance canister on the distributor from the carb. So at idle, I'm not getting any vacuum advance. Connected my vacuum pump to the advance unit and it will advance with 15" of vacuum. I've sprayed carb cleaner in the vacuum port on the carb and the engine will stumble while doing it so I don't think the passage is clogged.
Any ideas as to what the problem is? I'm frankly stumped.
Also, does anyone know what the diameter of the vibration damper is on a non R series engine?