Scooter drives withered at most 40?

I have a problem again… My scooter spins a little I bought it from someone a long time ago, he didn’t go at all. Then I tinkered a little and he goes the following is my problem… the scooter drives a maximum of 40! He pulls well up to 40 through, but from 40 he just stops and gets slower again. Then I can put on again and from 40 he just turns back Oo? I tried with Ori exhaust and with sports exhaust, just like with 6.5g Weights (the originals) and with 4G weights. But nevertheless exactly the same… From 40 it stops simply, as if a CDI throttle or something were installed, but which actually cannot be. I have to say, I can not adjust my carburettor by stand gas screw… It is only half in, because otherwise it comes against the gas pull. I have the end of the gas pull, what goes into the carburettor actually properly built, the side where the slot is goes to the stand gas screw. But the slot is t too narrow for the screw. But when I play with the gas on traffic lights it does not go out. Furthermore, I have to hold my hand before the carburettor every 2nd day, and then kick with it to start. /edit: I just dropped one I also removed the manual choke… With the carburettor I closed the hole with aluminium foil.. Is that bad? Can you help me ?