I have a Grubee Skyhawk 66cc. I have a 36 tooth chain sprocket so it's not unusual to lose power on steep hills. I was climbing a long hill yesterday and experienced that gradual loss of power to the point where I had to help it and pedal. I got to the top of the hill and the motor stalled out. On attempting to restart, when I let the clutch out my rear wheel locked up and wouldn't turn. I tightened the clutch cable, I loosened the clutch cable, I adjusted my flower nut one notch looser, nothing worked. I pedaled home. I don't know whether I toasted my clutch or my engine, thinking it's my motor. Okay wizards, please and thank you, what say you? And of course suggestions for the repair are appreciated. ride safe