Looks like you are getting a lot of spitting out of the carb. Almost sounds like you are running rich not lean, which is the normal things with carbs. Lets start by checking the valve clearance, as well as the flywheel key to make sure it isn't partly sheared.
If those check out OK, the lets go back to the carb, and make sure the air bleed holes are clean. those are the holes just inside the intake side of the carb. Also pull that screw that goes down from the top of the carb, and make sure it is clean as well as the passages.
If those check out OK, the lets go back to the carb, and make sure the air bleed holes are clean. those are the holes just inside the intake side of the carb. Also pull that screw that goes down from the top of the carb, and make sure it is clean as well as the passages.