Hot Start Issue Choke stuck?

TJ covered it nicely. If you'ld like an illustration it was introduced here:
Heated Air Intake and "Vapor Saver" (Session 271) from the Master Technician's Service Conference

The best book to have is the Plymouth Service Manual. You may find a scanned edition on line for 74. I personally like to have a print copy as well.
A lot of scanned original sales info as well as service bulletins are here:
The 1970 Hamtramck Registry Library Page (1970 - 1974)

Your car may have a sticker under the hood with factory tune up specs and vacuum hose routing. I forget what year that started.

Factory carbs and timing of these years are calibrated a bit different than you would do with an aftermarket carb. Late 60s they focused on reducing CO and HC at idle and on deceleration. Then on reducing NOx as well. Mentioning this so you understand the goals of the original setup which is the baseline regardless of what you do.