My answer to What is the blower on a boat and what functions does it serve?
Answer by Desmond Last:
The blower is an essential safety device. It could save your life. On older petrol powered boats with carburetors I would rather swim the Atlantic than start an engine that does not have one. On a hot day your engine bay will get warm. Any fuel vapor will collect in the engine bay. The blower will extract any petrol vapour.
Safety Tip One: When you board your vessel do not start the engine until you have switched on the blower for a good 5 minutes. Make sure the blower is actually working.
I always advised boat owners to lift the engine hatches and check for fuel and oil in the bilge – coolant too.
Safety Tip Two. On the older petrol boats with carburettors do not over pump the carburetor and flood the engine.
Safety Tip Three. Make sure your alternator is a Marine Alternator with a Spark arrestor.
Safety Tip Four. Make sure the air filter has a Flame arrestor.
Safety Tip Five: Make sure your fire extinguishers are in date.
Diesel Boats have blowers too.