Thanks guys. I found a used carb on ebay, same model as mine for $30. I carefully disassembled it and compared the jet sizes, air bleeds etc. against what should be in there for a standard 1972 production A12 engine. All jets and bleeds matched against the chart you provided. Cleaned and blew out all passages. The accelerator pump check ball was missing and the choke unloader unit diaphragm was ruptured so used my old one that was good. While turned upside-down the primary emulsion tube fell out. Good deal. All holes were clean. The secondary tube wouldn't come out so figured it was OK. The secondary part of the carb is never used anyway as I never run the engine RPM high enough for it to open Installed a new carb kit and is now all reassembled. Waiting for zero degree weather to go away before I install on the engine and check it out. I don't use my windmill boom truck during the winter so it's parked in the non heated part of my building. I am using a electric fuel pump that I originally installed 14 years ago. It keeps the fuel level in the sight glass right on the center dot. I checked the fuel pressure at the carb inlet anyway after starting to have problems to see what it was doing and it was 2-3 psi.