"carb cleaner around the #2 throttle shaft shows a slight drop in idle, but nothing more around the rest of the carbs or intake.

I really do not think this is the problem. I dealt with a poor intake seal once before and know the sound fairly well. High pitched hiss/whine - not getting that now."

If the idle speed changes when you spray carb cleaner around #2 throttle shaft, or anywhere else related to the intake, it *IS* a problem. False air doesn't always make an audible sound - in fact, it very frequently doesn't. Your best hope with these carbs will be to get the engine to run smoothly enough that you can drive it gracefully, but I wouldn't count on being able to get good economy given that you have a known vacuum leak. The amount of unmetered air coming into the engine will vary depending on engine load and engine speed; part throttle (high vacuum but low volume of air/oxygen) and wide open throttle (low vacuum but high volume of air/oxygen) and every combination in between will result in a different volume/amount of unmetered air entering the engine - and there's no possible way you (or anyone) can tune a worn carb to correct this. You can mask it, but you can't correct it. If you're looking for driveability, the closest you can get is to set them so rich that the mixture is never on the lean side regardless of engine speed/load. Which means your economy will remain poor, because the mix will be way too rich all of the rest of the time. Trust me: it's been tried.

With the price of fuel ($3.71 in Portland today), I'd guess you'd recover the cost of having a pair rebushed in a matter of a few months in fuel savings alone.

Worn carbs cannot be properly tuned. They just can't.

Cameron
122SC, 444
Rose City