Hi Mitty,
I would check to see that the pulse port is open all the way to the case. The pulse hole in the carb is next to the aluminum pump cover on the back of the carb. Also check for leaks which can cause the problem. Make sure that the fuel pickup is in gas you point it up. I balance my fly wheels with a Hi-point balancer. Any good machanical balancer would do. Do search on flywheel balancing or Wacker will balance them for $15.

Dave