A carb that requires some choke to idle has a vacuum leak. Get a can of starting fluid and with the motor idling at normal temperature, spray the fluid on the carb in short bursts at every angle from top to bottom. Pay close attention to the manifold/throttle base gasket (it should be a diffuser gasket, properly tightened) and to both ends of the throttle shaft. Pause briefly between bursts. Listen to the motor. If the RPM changes, you have a vacuum leak. It could be as simple as tightening a nut or screw to stop it. If it leaks at the throttle shaft, you will probably need bushings and a better shaft. As well, you may want to check your needle valve. At your altitude you need a #548 needle. If it is a #547 you are running too rich.As far as the PCV valve is concerned, the only reason to remove the spring and plunger is sludge buildup. The only reason for that is neglecting to perform regular, routine maintenance.