Still hesitates off throttle...

Thanks for the replies guys.
The balancer is new and I also confirmed the timing mark is correct.

I had the carb off and checked that the vac advance is plugged into the ported connection. I confirmed that it has zero vacuum at idle with the throttle plate closed then builds to about 18 in/hg as the throttle opens, then backs off to 15 inches at about 2500ish rpms. It stays at 15 inches to full throttle.

AJ/FormS said

the vacuum advance should not start until something like 1600 or even 1800 rpm

Click to expand...

I think this may be the problem. The vacuum on that port goes shoots to 12 inches almost immediately - before I hit 1400 rpm. The vac advance starts to move at about 8 inches. I will check the manuals about adjusting the vac advance to get it to kick in later. Thank you.