RedactedNarrative: This accident occurred on 08/23/16.  Four people were at Avondale access area in Hendersonville, TN between the times of 1700 and 1730.  The purpose of them meeting was to attempt to fix Owner’s boat.  They launched the boat using the ramp at Avondale and proceeded toward the nearest point close to the "No Wake" area.  The boat had not been used much and was reportedly having a problem with fuel pressure.  
  
  While the boat was near the point Victim put a diagnostic tool onto the boat to measure the pressure.  At this point Victim told Operator1 to start the motor.  The motor started up fine and Victim said the pressure looked normal.  Victim suggested getting it on plane to see what it did.  Operator1 got the boat on plane and headed across the lake in a Southeast direction, toward Wilson Co.   
  
  [Occupant1 was sitting in the seat on the port side closest to the bow.  The driver, was sitting at the control, which was on the starboard side closest to the bow.  Occupant2 was sitting on the port side closest to the stern.  Victim, the mechanic, was sitting on the starboard side closest to the stern.]  
  
  As they got close to the Wilson Co side of Old Hickory when Occupant2''s hat blew off.  Operator1 slowed down and circled the hat.  They attempted to grab it but missed on the pass.  At this time Operator1 put the boat in reverse and the explosion occurred.  
  
  The explosion was in the stern of the boat.  This boat had three hatches in the stern and the explosion blew open both side hatches.  With the side hatches open the flames came out of the engine compartment and started the back of the boat on fire.  Victim at the time was still in the stern of the boat and was over the hatch at the time of the explosion.  They looked for fire extinguisher briefly, but they were under the bow in a compartment.  Everyone jumped off the boat at this point.  A passing boat stopped and threw PFD''s to the four in the water and got them aboard their boat.  They were transported back to Avondale access.  Victim was the only person injured, receiving flash burns.  He denied medical treatment on the shore but drove himself to Sumner Medical.  He was later discharged at 2330.  
  
  Victim, the mechanic, believes an issue with the carburetor was the problem leading to the explosion.  He felt that the float was hung on it causing fuel to leak out into the engine compartment.  When they put the boat in reverse he believes a faulty wire must have grounded causing a spark which ignited the fumes.