With one of the 'chokes' disconnected, chances are good it's not going to runcorrectly until the engine is up to operating temperature .
You need to check to see that the choke is fully closed .
Your high rpm issue could be a tear or hole in one of the carb diaphragms .
There are three fasteners holding the rocker arm cover on, two 10 mm nuts that are in the cooling fin area of the head .
The other is a 13 mm nut in the center of the rocker cover .
It is a problem area, it gets tightened up too much and the threads pull out of the cylinder head and the threaded stud gets loose .
My guess is that the stud is not doing it's job, that's why you have an air leak in the area of the gasket between the rocker cover and head .