the thumb lever on the cns carb IS the choke lever.
instead of having a typical choke like most carbs that restricts air into the carb to richen the mixture,the cns carb choke does the opposite. It adds fuel to the mixture to richen it for easy starting. In reality the cns choke works backwards in comparison to the standard type of choke. The cns choke is "on" when the valve is open, and "off" when the valve is closed. A standard type choke is "on" when the butterfly valve is closed, and "off" when the butterfly valve is open.
The reason your idle is so high is because you may have the carb slide in wrong (180 degrees off). if you take the top off the carb and pull the slide assembly out of it, look closely at the slide.
you will see 2 notches in the sides of the slide 180 degrees apart.
one slot will be long and one will be short.
the long slot goes to the right side of the carb (when looking at it from the top). there is a pin cast into the inside of the carb body that this long slot must line up with.
the short slot goes to the left side of the carb and should line up with the idle adjustment screw. normally, if the slide is put in wrong you will have wide open throttle ALL the time because the slide wil be jammed open in the carb. If the short slot in the slide is lined up with the pin in the carb, the slide can not close all the way.
Another thing that may be causing you a problem ios the air-fuel adjustment screw...you may have it set too lean, but if it was set too lean, you would still have some throttle control.
My guess is that you have the slide in the carb wrong and it's bound up and stuck wide open.
Once you put the slide in right, you can adjust your idle to where you want it with the idle adjustment screw on the left side of the carb.
Another possibilty is that your slide is in right, but you have the idle adjustment screw screwed all the way in. This will hold the slide open too far and give you the same results (almost wide open throttle all the time).
:-/
