Take a deep breath, you can fix this.
First, loosen the linkage on both of the carbs and see if you can sort out if the binding is occurring in just that part of the system. Then, connect one carb and see what you get. Connect the secod up and see if you can duplicate the issue. Sometimes its just the linkage is out of adjustment and out of square, other times you will need to make a new rod from the bell crank to the linkage,. But this can be resolved. That linkage set up you have is pretty reliable so something is up. And, yes, as mentioned earlier, you should add a second spring..
