Which of the following is a common sign of boat engine trouble?

Steam or smoke coming from the engine is indeed a common sign of boat engine trouble. This condition often indicates that the engine is overheating, which can be caused by several issues such as a low coolant level, a malfunctioning cooling system, or even engine blockages. Overheating can lead to severe damage if not addressed promptly, making it crucial for boat operators to be observant for such signs during operation.

On the other hand, an engine that accelerates rapidly typically suggests that it is functioning properly, as this is what you would expect from an engine under normal conditions. Similarly, if the boat is moving smoothly and the engine’s sounds are normal, these are indicators that the engine is likely in good working condition. Thus, the presence of steam or smoke serves as an important warning sign that requires immediate attention to prevent further damage to the engine or the vessel.