What is a common cause of overheating in marine engines?

Low coolant levels are a common cause of overheating in marine engines because coolant is essential for regulating the engine's temperature. When the coolant levels are insufficient, it cannot absorb and dissipate heat effectively from the engine. This leads to increased temperatures, which can cause significant damage, including warping of the engine components or even complete engine failure.

In contrast, while clogged fuel lines can disrupt fuel flow and affect engine performance, they typically do not directly result in overheating. Similarly, a damaged propeller can affect the boat's speed and maneuverability, but it does not influence the engine's cooling system. Lastly, a faulty throttle response may lead to power issues or engine stalling, yet it does not directly contribute to overheating. Hence, maintaining appropriate coolant levels is crucial for the safe operation of marine engines and preventing overheating.