Yamaha Aerox starts only with startpilot

To my problem. I have a conversion on my aerox behind me. It also works everything, only he doesn’t want to start. I always need startpilot. And then also not directly the first time. It runs as long as the spray is enough and then goes out. The third time it works but then. So a sparke is 100% there. The carburettor is also OK, otherwise it wouldn’t drive. But it’s not perfectly set yet. A thermostat is not installed, but that’s not absolutely necessary. I It’s not 1:50 in the tank. I was a bit sloppy. But I have fueled petrol again today, so it’s not (more) too much engine oil in the tank. But now my carburettor setting doesn’t fit. However, the setting should not be so decisive that it doesn’t start. In addition, it starts up to an hour after driving on its own. So as long as it’s still warm. The warm helps the engine to start, but the scooter never stands cold. The cold is also not the reason I think. However, it may be that the petrol in the hose vlt runs back during the service life and does not get gassed when kicking or with e starter. Many conjectures and ideas. I don’t know any more and hope for help. Mfg