The "choke" on SUs and Strombergs isn't really a choke. There is no extra
butterfly upstream of the venturi. The choke cable controls both an extra
fuel jet and a fast idle cam. Another good feature on those carbs is no
need for an accelerator pump jet.
What is it like to live with one of these? You don't pump the gas pedal
before cold starting, and you can't flood the engine by pumping the gas
pedal too much. Also, even if you have the "choke" pulled out all the way
when the engine is warmed up, it will run rough but generally won't flood
itself and stall out. Finally, there was no electrically heated automatic
choke element to pull off the choke before the engine was properly warmed
up.*
On the other hand, they get a bad rap because they will still work when they
are very worn out and have air leaks, but are impossible to keep in tune in
that condition.
Prior to owning a carburetted Volvo, my previous car had a Holley
carburetter that was far more complicated, difficult to adjust, and pretty
much inferior in every possible way to the SU. What a difference!
*electrically heated automatic choke was the worst anti-pollution device
that Californians ever inflicted on people living in winter climates