A quick thought: is the carb a 1406 with electric choke? If so is there a good 12v source to the hot side of the choke coil? (and ground tot he ground side?) If it's disconnected, or the power lead run thru a switch of some sort (like an oil pressure switch or something) it might not be getting power to open up the choke blade. This will cause it to run rich as hell, appear to warm up very slowly and the secondaries won't open. (Don't ask me how I know these things.)
Again, if it's an electric choke, check for 12v across the power leads of the choke coil.
hth,
