Need part number for a new carburetor

Hi,
I cannot say positively, but it seems that the part number is 640084B. Tecumseh no longer in business (at least not the engine end, but still "owns" the refrigeration compressor business.) You did not give the second set of digits, i.e. 67xxx so I am not positive. A link to parts breakdown is:
Tecumseh Parts Lists Tecumseh Engines Parts lists
And be aware that the carbs were made in Czechloslovakia toward the end.
Peace,
Clarke