If operating the primer improves the situation, the problem is lean mixture. If you have verified that there is adequate fuel flow from the tank to the carburetor, and you are confident that the carburetor is now in good order, the remaining possibility is that there is an induction air leak downstream of the carburetor. Because it is a Powertorque, history suggests you should start by examining the three O rings: two in the inlet pipe, and one under the starter. Intake air leaks on Powertorques traditionally involve one of those three possibilities.
