Read post #20 and 23 twice. Then go back nd read post 20 again.
Use a pressure/vacuum tester gauge such as a mityvac. (to test the carb needle/seat and the gas tank venting. (If it's the Nikki clone type single barrel carbs the needle/seat can be ok but internal seals above the plastic can...
You asked: Has anyone tried running one of these engines WITHOUT the counterweight inside???
I thought about eventually removing the counterbalance with my knocking briggs that I set back but have not had a chance to try such yet. I think the knock on this one is the counterbalance guide...