What should you do immediately if a boat motor catches on fire?

If a boat motor catches on fire, the priority is to stop the source of fuel that could exacerbate the fire. Shutting off the fuel supply helps to minimize the risk of the fire spreading or becoming more intense, as continued fuel flow can lead to a larger fire. After securing the fuel supply, using an extinguisher to put out the fire can prevent it from causing serious damage or leading to more dangerous situations. Having an appropriate fire extinguisher onboard that is suitable for the type of fire is crucial for effectively addressing the flames.

Attempting to restart the motor does not make sense, as it could further ignite the flames due to the sparks or additional fuel being introduced. Jumping overboard is often not the best immediate reaction because it leaves you vulnerable and does not deal with the fire directly. Finally, signaling for help is a reactive measure that should follow addressing the fire; immediate action to suppress it is critical to ensuring the safety of everyone on board.