Why must you operate the exhaust blower before starting a boat's inboard gasoline engine?

Operating the exhaust blower before starting a boat's inboard gasoline engine is crucial for removing fuel vapors that may have built up in the engine compartment. Gasoline is volatile and can produce vapors that are both flammable and potentially explosive. By using the exhaust blower, you help ventilate the area, thereby reducing the concentration of these vapors before the engine is started. This practice significantly enhances safety on the boat by minimizing the risk of fire or explosion, especially in enclosed spaces where vapors can accumulate.

In comparison, while cooling down the engine and ensuring the battery is charged are important considerations for overall boat operation, they are not the primary reasons for using the exhaust blower before starting the engine. Additionally, removing water from the bilge is an important maintenance task, but it does not directly relate to the necessary precautions for fuel vapors.