A boat engine, also known as a marine engine, is a type of internal combustion engine that is specifically designed to power boats and other watercraft. Boat engines come in a variety of types and sizes, ranging from small outboard motors to large inboard engines.

Outboard motors are typically mounted on the transom of the boat and are used for smaller boats and watercraft, such as dinghies and fishing boats. They are portable, easy to install, and provide good maneuverability. Inboard engines, on the other hand, are mounted inside the boat and are used for larger boats, such as yachts and commercial vessels. They are more powerful than outboard motors and provide better fuel efficiency and speed.

Boat engines can be powered by gasoline or diesel fuel, and can be two-stroke or four-stroke engines. Two-stroke engines are simpler and lighter, but tend to be less fuel efficient and emit more pollutants than four-stroke engines. Four-stroke engines are more complex and heavier, but are more fuel efficient and emit fewer pollutants.

Proper maintenance and care of boat engines is important to ensure their longevity and reliability. This includes regular oil changes, filter replacements, and inspections of the engine's components and systems. Overall, boat engines are an essential component of any watercraft and play a crucial role in its performance and safety.