A faulty diaphragm would pump little or no fuel. My car had a rich bog which was cured with a smaller acceleration pump jet.Add my name to the list of Solex users whose carb works great except for a couple of annoying habits- it bogs down momentarily when accelerating from idle (faulty accelerator jet/diaphragm?).
Bob, if you're asking whether Alfa ever shipped a 750/101/105 car with a single downdraft Weber carb, I'm pretty sure the answer is no. DCDs came on Fiats and Cortinas, but no Alfas out of the factory.I,too, am planning to use the Weber, but am curious if it was a valid carb at build time (1959). I always hear that it is "period correct", but did Alfa actually ship 1300s with a single down draft carb?