My 318 w/850 Thermoquad never idles well in gear, and stumbles off the line

Yes, the carb was rebuilt before installation. Also all baselines regarding secondary air-door and the primaries metering rods were set-up prior to installation as well.

It is not so much a stumble coming in to the primaries, it is a stumble because of the idle circuit I do believe. I am sorry I cannot include every detail in my first post so that you all know what level of troubleshooting/settings I am at.. as I simply do not remember them at the time ;).

I do have a solid return spring on the throttle arm, so that the throttle is indefinitely returning to idle everytime. I cannot say whether or not it is retuning to the same spot internally though.. I seem to recall the bushings seemed ok at the time when I dismantled it.