Re: Idling "problem"
I used to run mechanical, but went back to vacuum for some reason or another. If you think it's running too rich which is what is causing it to not idle back to "normal", then why would pulling off the vacuum line when it's fast idling take it back to normal idle? Could be I guess, but I don't understand why. There is more vacuum at higher rpms, hence the advance it timing, but when you let off the gas, then I would think it would drop the vacuum pressure and the timing would return to normal. Also, if the advance was hanging, then it would "not" go back to normal by removing the vacuum line (because it would still be hung). With that being said, it's pulling too much vacuum still (at least I think) and that's why it's fast idling. With that being said, then perhaps you are right in the fact that it's too rich, hence the higher rpms.
btw - This thing is by no stretch of the imagination stock!