A 1987 Sea Runner cabin cruiser with a single Mercruiser gas engine had just refueled.  The operator stated that he had run the blower.  The engine would not initially start.  The operator removed the air filter and noticed that it was getting fuel.  He replaced the filter and this time the engine started.  While dock lines were being cast off, there was an explosion in the engine compartment and the vessel caught fire.  The dock boy cast off, pushed the vessel away, and shut off the marina gas pump.  All occupants jumped into the water and were rescued by a passing boat.  They were taken to a local hospital, three with serious burns.  One occupant stated he saw about 1/4 gallon "of a liquid" in the bilge.  The boat was a total loss.
Essex