Piaggio TPH 125

Piaggio TPH 125 no longer runs Hello together, I have a “small” (hope i) problem with my scooter. I have a TPH Built 1996 125ccm 16000 KM. The scooter stood at the previous owner 3 years in the garage. Now I got it given. We have cleaned everything new spark plug new brake new E-coke and that included. He also came loosely over the TÜV. Now to the problem: I had hit him a bit, because of the long service life. Then I thought, I once refueled V-Pow he. (I know it doesn’t help, but the thought and hope counts). At the beginning everything went well, suddenly at a traffic light the engine ran quite ill. When I wanted to start he took no gas and just went out. But I got him again and continued. Second traffic light again the same, only that he didn’t go on anymore. wait after about 15 minutes and alert the girlfriend (to pick up) he ran again. But only 10 min, then it started again from the new one. (15 min wait, drive again) Zuhaus e arrived I removed the spark plug, it was a bit dark but actually looked normal. Now it went on again. I drove a small test round and suddenly???? Yes I stopped again. Same problem. Only that it no longer concerns at all. Could it push him home (25C outside temperature in the shadow) a 3/4 hour. Now my question what can it be??? Can it be the carburetor that the swimmer clamps? Or the V-Power? Thanks already