What happens when it sticks? I would think this would happen a lot with trucks that have sat for a while.
I had one stick on a '54 IH 1/2 ton with the Silver Diamond 220 engine, and lost one cylinder at a time until it wouldn't pull anymore. When I opened the hood, the carburetor was a solid block of frost.
I assume it was stuck closed. If open is normal, I suspect that sticking open doesn't do anything after the engine is warmed up. But I'm curious. Does sticking in between open and closed have much of an effect?