RedactedNarrative: Operator was cruising on the lake and stopped to pull two skiers. Operator advised that he took the vessel from neutral to forward and the vessel paused. He heard an explosion and he and his son attempted to put the fire out and then abandoned the vessel. All made it to shore at 201 knob hill circle. While interviewing the operator i found that he had not implemented the use of a blower to vent gasses from the engine compartment most likely causing the vessel fire. Operator and one occupant received minor burns on feet from initial fire/explosion; Occupant suffered a minor burn to left great toe resulting in blistering; Operator suffered a 2nd degree burn to left ankle