I am happy for you, but your workaround may mask other problems. I am not a tech, but I have been researching and directing efforts on these engines for five years now and have been around these cars since the 1970s when these cars were new. The venturi flap is a vital cog in the system for these engines.
If you restore the venturi flap to its proper position, which is just closed at idle, and the car will not idle then you should open the idle screw to introduce more air at idle. There is an iterative procedure for setting idle that involves getting the proper air to fuel mixture at idle then if idle is too low you first stop the engine, richen the MIP idle setting then set the fuel to air mixture by manipulating the idle air screw and observe resulting idle speed. Typically once these have been setup properly they do not go out of adjustment unless someone ignorant of how it works fiddles with linkages. If all bushings are good and linkages are as they were when the engine idled well then you do have another issue.
Also, if you haven't already you could check your ignition system for optimal setup. That can affect your idle speed stability and is the first step for the recommended procedure for idle optimization.
I have the information from the service manual and some other writeups describing how to set the idle. Let me know if you want me to PM that information to you.