Speedfight 120 stator coil blown x2 in 1 week!

My mate has a speedfight 120, his stator originally packed up and shut all his lights off.. he then replaced it and it has blown again within one week?. What could be the cause for this?, i checked his fuse and he's got a 15amp fuse in there when the standard is a 7.5 iirc could this be the reason? there is little or no power coming from the stator. I told him the fuse might be the reason but i am not completely sure?.. any help appreciated thanks

 

I'd say check all wiring. In my speedfight (70cc) it's a 5 amp fuse.