Define "carb has been inspected and cleaned."
I would remove the carb and take it apart completely and soak it in a dunk tank a couple of days. Then reassemble with new parts from a kit and put it back on the motor.
On one of mine I had to do the head gaskets. It would puff smoke out the cyl / head joint on start up. You would only see this without a hood. Even with the leaking HG the motor still ran smoothly.
I would remove the carb and take it apart completely and soak it in a dunk tank a couple of days. Then reassemble with new parts from a kit and put it back on the motor.
On one of mine I had to do the head gaskets. It would puff smoke out the cyl / head joint on start up. You would only see this without a hood. Even with the leaking HG the motor still ran smoothly.