Engines producing 50 peak horsepower are often used to power smaller motorcycles, motor scooters and farm tractors, as well as seeing use as outboard engines for small boats. The precise uses of a given engine depend heavily on its design, however, as engines suited for use on land are often designed differently from engines designed for use in watercraft, and engines suited for tractor use may be too heavy for use on a motorcycle.
Smaller gasoline engines in the 50 horsepower range often use a single-cylinder or V-twin engine design, especially when used for motorcycles or motor scooters. Heavier in-line engine designs with three or four cylinders are more common in marine applications or on tractors and riding mowers. Most such engines are two-cycle designs that complete the engine cycle in two strokes and that use mixed engine oil and fuel since they are cheaper to design and build than four-stroke engines.
While two-stroke designs are louder than and less durable than the four-stroke engines typically used in passenger cars, they are also lighter for the same power output. However, four-stroke engines producing 50 horsepower are produced for outboard motor use and are particularly suited for fishing boats since they are quieter and produce less vibration that can drive fish away from the boat.