Otto - Carter 964s carbs are not expensive, nor or they rare.
There are probably 8~10 on ebay at any given time.
Given your posts, I would suggest it might be prudent to just buy another core. Get the vendor to show pictures on the stamped number, as well as the number on the metering rod, and other casting numbers.
My Dad used to have a saying about "spending good money after bad".
Jon
