One horsepower is the power needed to raise 550 pounds a distance of one foot in one second or the power needed to raise 33,000 pounds a distance of one foot in one minute. It does not care whether the engine is fueled by diesel, gasoline, or lighter fluid. Work accomplished over a specific period of time is what it is all about. It can be an air cooled lawnmower, a Wankel, a turbine, or freight train. It is all about work accomplished with time as a factor. People, including myself, have been fooled by the ratings.