Hi guys I'm new to this. I'm hoping someone can shed some light to my sons scooter problem. Here goes. My sons yamaha starts fine. When taking it for a ride it pulls away fine. If you open the throttle full its OK but if you ride the bike with about 1/4 throttle its OK to start off with then after a short time the bike starts to die. If you give the bike full throttle and the bike still dies. theres no way to recover from it until you cut the bike and restart. It's had a new spark plug. I thought it may be the automatic choke so to eliminate it I changed it for a manual one. Adjusting the air mixture doesn't really help. It a 2 stroke. If anyone has any ideas that would be amazing. Thanks.