This article somewhat long, but may aid in understanding:

http://www.thecarburetorshop.com/Automaticchokes.htm

Personally, I replace any style automatic choke on my vehicles in favor of manual chokes. Very functional, very reliable, but everyone to their own opinion.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop