RedactedNarrative: Operator stated that he filled PWC with fuel in the morning and his daughter was riding the PWC earlier in the day.  The PWC was parked on shore station until he started to ride it at 1415 hours.  Operator stated he moved out past the shore zone (118 yards) an SNW speed.  The PWC acted like it lost power or had something get into the water jet and then caught again.  Operated stated he hit the throttle and then remembered seeing the PWC below him as he was launched into the air with the PWC on fire.