You are just a power boat. If you look at the rules you would not need a fire extinguisher or a throwable flotation device even if you were gas powered. Here are the requirements:
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1) Personal flotation devices:
Boats less than 16 feet in length and all canoes, rafts and kayaks, shall carry one Type I, II or III wearable device of suitable size for each person on board.
2) Sound devices: A boat less than39 feet 4 inches (12 meters) must carry a sound signalling device such as a whistle or compressed air horn.
3) One B-I type approved fire extinguisher when no fixed fire extinguishing system is installed in machinery space(s). (Fire extinguishers are not required on outboard motorboats less than 26 feet in length and of open construction.) No B-I type extinguisher is required if an approved fixed fire extinguishing system is installed in machinery space(s).
4) An approved carburetor backfire flame arrestor for inboard motors not exposed to the atmosphere above the gunwhale.
5) An effective muffling system for the exhaust of each internal combustion engine.
6) A ventilation system, the particular type dependent upon when the boat was built.
7) Lights (required only when underway or at anchor between sunset and sunrise, and during periods of restricted visibility).
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Thus you need a PFD for yourself and a sound device. Since you are under 26' you do not need a fire extinguisher. Items 4,5,6 do not apply. You need an all round white light if out after dark. Also, I believe that since you are a power boat you will need a boater's license.