I have a new gy6 scooter with a jj1p39qmb engine. I have tried to adjust the idle speed and found something strange. The idle is actually OK, but only if I close the idle screw fully (clockwise). As soon as I open the idle screw the idle speed drops and the scooter runs more unsteadily.
As I said, the scooter runs OK on idle, and otherwise too. But I'm a little bit surprised that I have to turn the idle screw full and ask myself if that's really OK.
I mean the idle air/fuel mix screw on the side of the carb.