[DavidG]

If you study the illustration below (from the Service Bulletins and reprinted in the book) you can pretty much figure out the evolution of the carburetor that took place in a very short time (likely all in the month of March and early days of April, 1932). Not shown is the round accelerator pump rod that you mention, but it is implied given the notes regarding its replacement and the replacement of the other parts that changed to accommodate the stamped 18-9578 kicker (Ford terminology).

The die cast center section was changed several times during that evolution which is also inferred in the illustration (the change to the accelerator pump within), the change in the float valving, and the incorporation of the spring-loaded ratchet that was attached in the second version of the four float bowl cover versions (the first had none). (The third version of the float bowl covers is not shown; it was the same as the fourth version except it lacked the riveted on curved baffle on the underside of the cover.) Which of these changes correspond to the 9001 to 9004 progression of patent numbers, I know not.

A couple of years ago a cutaway example of the first version of the carburetor showed up on ebay. Likely it was one of a kind, at least in terms of survivors. I have photos of it, but I'm away from the computer that has them in its files.

The photo below is of the carburetor on the flange block engine in my early phaeton. While I do not remember what the patent number is on the float bowl cover, I'm pretty sure that the letter on the cover is 'C' for March, which makes sense as the engine was built on April 4th. Note that the float bowl cover is the third version mentioned above, which leads credence to my theory that most of the changes to the carburetors took place in March and early April. (It is only a theory as I have no documentation, but then I doubt that such documentation survived.)