Frank and Diseasel,

Thanks for your replies.

Frank, I've tweaked the mixture screw in the tower several times now but never in a scientific manner. You say back it off, CCW and eighth of a turn then start the car, until it doesn't start or what? I'm assuming this is like an old carb adjustment for the mixture... get it to where it runs reasonably well then add a quarter turn for good luck. Sorry, not being flippant. How do I know when I've adjusted to the "right" place on the metering screw?

Diseasel, I've done a smoke test, that's what found the bad rubber bellows. I've also sprayed carb cleaner on different parts of the engine listening for RPM changes. Is there another way to see if anything is leaking? I've also measured the engine vacuum at idle and it seems good, but I honestly don't remember the reading. Do you know what it should be?

Thanks to both of you!