RedactedNarrative: Operator of vessel #1 was getting underway to exit his slip.  He needed to make a port side turn in order to exit the marina.  
  
  He placed the starboard engine slightly forward and the port side engine in reverse.  For some unknown reason the port side engine revved up and caused him to back into vessel #2 causing property damage.  
  
  The port side engine was thought to be stuck in the open throttle position.  He pulled the throttle lever to the rear then pushed forward on the lever correcting the throttle.