Most carburetors, including those on tillers, have identification or part numbers either stamped on the carburetors themselves or stamped on tags attached to the carburetors. The two most common locations for the stamped part number are on the carburetor flange or on a brass tag wired to the main body.
It is also possible to narrow down the carburetor part number based on the brand of the machine, the material that the carburetor consists of and the number of barrels it has. Carburetors manufactured with tags are often impossible to identify if the tags are no longer on the units. Another way to identify a carburetor is to use a carburetor identification service.