RedactedNarrative: The occupant of the boat stated that the vessel was beginning its trip and was about to reach the mouth of the harbor when the engine stopped.  The operator turned off the key and tried to restart the engine which resulted in an explosion in the engine compartment.  The engine compartment hood was blown off the and a fire resulted.  The operator stated there was an operational fire extinguisher on board, but no attempt was made to use it because the vessel was was engulfed in flames so quickly.  All occupants jumped overboard.  It is unknown if the operator turned on the exhaust blowers prior to starting the engine, but it is unlikely.   Neither the operator or occupants could remember.  The operator had less than 15 hours boating experience.  The watercraft burned and sank and was later recovered.  It appeared that automotive parts (hoses, fuel pump and copper lines to the carburetor and fuel pump where not flared, were used on the vessel's engine.  The fire hot spot appeared to be in the stern area and down the middle of the watercraft leaning towards the gas tank in the bow.  The probable cause of the explosion was the use of automotive parts in a marine application which resulted in ignition of spilled fuel prior to starting the engine.  The operator's failure to turn on the powered ventilation system brough fresh air and expelled gasoline vapors from the engine compartment.
NameOfBodyOfWater: Mississippi River
NearestCityTown: Elash                         