all of a sudden problem with 70 vw bug

Here is exactly what has happened. The car was running really good -  really good. I recently moved out of the city but when I was there all the traffic and bad drivers got me to really pushing it to get ahead of bad drivers, make lights, etc. I know that sounds like I was the bad driver but I never did anything to affect other drivers. Then I moved out of the city. For a while there was dirt in the tank and it was conking out at speed on the highway but I had a mechanic fix that by draining the tank, installing new filters front and rear and clearing out the gas line. That was over a year ago and the car was running really great. I used an article by some pros to adjust the idle maybe 8 months ago and it realy hummed at speed and at idle. But I have been using a part gravel part potholed old blacktop road lately and it has shaken the proor beast to the max. So bad the stud  in the carb (the one to the front of the car) that holds the carb to the intake manifold stripped out and the other bolt (there are only two) loosened up. It was when the car first started revving up really high and then slowing down and dying out. When that started I was on that bad road and nursed it back home to have a look and the carb actually fell of in my hand! So I fixed that by putting a new stud in and tightening the other,. But that did nothing to stop that fast-then-slow phenom. I thought it was the choke maybe because the pin that many call the idle adjustment but it is not, not was flipping up --- scratch that ----- the cam with the steps in it that the pin contacts was rotating so the pin was at the highest step. It would not return or rotate so the pin and the throttle arm could drop to the lowest flat step. So there is something in that perhaps but I cannot find what. I tried rotating the choke assembly but it did nothing so I rotated it back to where it was. Besides that ring or collar around the choke was tight so how could that have been the cause that just happened in an instant?

I am really baffled. But back to your suggestion, how much of a job is it to replace that cable? I have never messed with that. Actually it is not a cable, its just a stiff wire isn't it? (1970 Beetle) There is no reliable VW mechanic anywhere around within 40 miles so I am stuck.