How exactly is electric choke supposed to work?

[strad]

This is a 1984 PCM 351 with the original 4160 carb and electric choke. This thing needs quite a bit of throttle to run during the initial warm up period. Once past that initial 1.5 minutes or so, it'll settle down and idle quite nicely if a bit on the high side (900 to 1000 rpms on the tach -- I need to adjust that).

I'm not convinced that the choke is operating the way I've read it's supposed to. It does operate mind you, just doesn't seem to go through the full stroke all at once or in a smooth fashion. How do I test it? Also one other thing. Do I need to re-jet this carb? it was originally run on the San Joaquin river delta (about 1-200 feet elevation I'd guess) and now I run it on Lake Mead (about 1100 feet elevation. It seems to run fine mind you.