RedactedNarrative: Owner had the engine replaced in the boat a few days before.  He  was checking the batteries and pumping the bilge.  He smelled gas earlier and ran the fan system to clear the fumes.  The vessel then caught fire.  The fire was contained near the carburetor.  The distributor was completely melted.  A fire suppression system was present in the compartment but failed to discharge since no extinguisher residue was observed.  No flame arrestor present on the carburetor.