Yes it would be your carb. Nothing to do with the tank or tank vent would cause a carb to flood. Clogged tank vents actually cause the opposite to happen. They will cause the tank to vapor lock and little or no fuel will flow to the carb.
Just done some searching and found out these carbs don't have floats. But as Bigfish said, something is keeping your inlet needle or valve from shutting off fuel flow inside the carb.
The good news is a new carb only sells for about $35-40. At that price I would just get a new one, slap it on and be done with it.
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