Poor throttle response

It all sounds like a carb problim.Not enough shot to get her going.Try the 50cc pump you will need to change the pump nozzel and maybe the pump cam.sounds like you have a holly on there.The pump cam will give a longer shot the 50cc will keep it from running out of gas and the nozzel will give it more flow.Sounds like tuning time.Good luck.Kocuda