I've just overhauled my Carter 32 RBS.
I noticed one trouble area that is not really well described in the shop manual. There is an air inlet at the base of the
 carb that is supposed to get the depression to the piston that helps to open the choke.
I said supposed because, between the carb and the choke assembly there is a seal that was, in my case, not sealing
 anymore. This was because, due to age I think, the choke was no more firmly tightened onto the carb.
The fix is simple, you just have to drill a little hole in the fixation stud near the air duct and use bolt and nut to gather
 the two parts. Then, you can simply test with a little rubber hose that depression moves the piston. Such a problem
 causes, not only a malfunction of the choke, but also an air leak that certainly doesn't help when you want to do a 
nice tuning of the engine.
Christophe  (SDC FORUM _ Sep 2011)