The vessel had just filled with gas at the marina dock.  The operator stated he turned on the engine blower, started the engine, but it ran poorly (sputtered).  The operator attempted to correct the problem by giving more gas, but the engine died approximately 100 yards from the dock.  The operator stated he then successfully started the engine, which backfired,  and exploded into flames.  He stated the blower was left on the entire time.  The occupants moved to the front of the vessel, grabbed child life jackets,(adult jackets were all in rear) and jumped overboard, where they were quickly picked up by marina personnel.  The vessel quickly became fully involved, and was allowed to drift into shore.  The Polk City FD attempted to extinguish with 2 20# fire extinguishers, but were unsuccessful.  The vessel was allowed to burn out.  Inspection later showed a flame arrester, but its condition, and the condition of any fuel lines etc. was destroyed.
Polk City                     