The two most common "carburetor problems" we see today are:
(1) ethanol in the fuel
(2) electronic ignition conversions
When customers call with idle issues, the first question we ask is if they have an electronics conversion. Generally they do, generally, points and condenser solve the issue.
In all fairness, I have yet to have anyone tell me of an issue at W.O.T.
Also, in all fairness, a large majority of the issues occur on older vehicles with generators as opposed to later ones with alternators. An electronics engineer told me that the electronics require a very stable voltage; and the alternator produces a more stable voltage at low RPM.
Not saying don't use the conversion; but am suggesting to keep the points and condenser in the glove-box; AND if you have a generator, convert it to an alternator.
Jon.