Okay.. Have had the same trouble.. while riding for about 5 minutes.. worked fine.. Come to a stop sign.. idles, motor stumbles then dies.. Starts right up.. Ride again, for a while.. stop, idle stumbles and dies.. What turned out to be for me..was the spark plug wire.. It was rubbing along the tubing for the frame.. and it work a slight amont of rubber off the wire,, that it allowed it.. the spark, to escape at that point insted of the cylinder head.. I moved the spark plug wire away from the frame and "happended' to see the spark. Try moving the wire away from the body of the scooter,, or don't let it touch anything for now.. and see if the motor stays lit for the duration of your ride. If soo.. it may have been grounding itself. Good luck and enjoys the wheels..