The most likely culprit is the carb float and/or float valve.
...the float is set too high...or
...the float valve is stuck open or partially open, caused by crud in the float bowl, or by build up of varnish on the end of the float valve from old gas.
You may solve the problem with a treatment of Seafoam added to your gas but...
more likely, I think your carb may need to be disassembled and cleaned.
There may be other possibilities but is what happened to my TW after sitting for six months, and I forgot to drain the carb before storage.