I have a cp17.5 on a Polini 64cc kit. It took a lot of digging to get it set up, but I think it is performing well if thirsty.
I didn't get anywhere before I had the air brake jet from Treats, check the rubber caps, there are hoses in the box you don't need... There is a lot to this carb that you don't need on a 2 stroke.
Mine will also take a piss on the floor if I leave the fuel line open. It seems to be a feature to prevent fouling the carb with fuel/oil. When the vacuum dissipates, all but the bottom of the float bowl will drain.
I think this might be why the CPs need the choke for starting, they are self drying. With a Bing, you can start it up and get down the block before you realize the fuel petcock is still closed.