Tp-11 why must you operate the exhaust blower before starting a boat's inboard gasoline engine?

The exhaust blower should be operated before starting a boat's inboard gasoline engine to expel the gasoline fuel vapors occupied in the bilge, preventing explosion.

Explanation:

The gasoline has the tendency of forming vapors which are heavier than air on evaporation and these fumes will get precipitated in the bottom of the boat i.e, bilge.

As the fumes are heavier than air, they can explode if placed in an enclosed region like bilge.

So the exhaust pump should be turned on until all the gasoline fuel vapors precipitated in bilge gets removed.

If the fuel vapors are not removed , it will cause explosion of the vehicle.

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.