Recently, I cleaned up an old Spree that was sitting in my garage. Carb was clean, and it started right up and idles fine (no jerkiness, which I assume would mean a dirty fuel system). When I get on and begin to ride, the power and throttle increase steadily, and the scooter runs smooth. As soon as approximately 20 seconds go by or i hit a slight ascension in the street, all of a sudden I lose all power (with throttle wide open). When I flick the throttle closed and open again, i get a sudden jerk of power, and then nothing again. I can kind of get myself uphill by constantly flicking the throttle and hopping forward, but would really like to know what is wrong with the scooter. It is as though the throttle loses its function sporadicly for no reason. Any ideas? Thanks in advance for the help.