I run a Carter WO downdraft carb on my speedster. Has worked flawlessly for over 20 years. Now it doesn't... Last time I used the car, it was perfect. Yesterday, I could not get it to idle. Kept stalling... I turned up the idle speed and got through the day at an annoyingly high idle. Obviously, something wrong in the idle circuit. Playing around on the web, I see that brand new, (made in China

), WO copies are being sold. Many of them listed on eBay by many "different" sellers, all with poor feedback ratings and strangely, nearly all shipping from Hebron, KY.
So, the questions...
1. Does anyone have any knowledge or experience with these Chinese copies?
2.
Does anyone know of a good rebuilder for a Carter carb?
I'll probably take it apart myself and see if I can find the trouble, but the car is currently on display in the Piquette Plant Museum, so not an opportune spot to work on it and test it. Therefore, tempted to have it professionally "rebuilt". Somewhat less tempted to buy a Chinese copy, but curious about them.