It seems to me that the manufacturers are marketing horsepower numbers that are only momentarily produced. The Yanmar and the 300 horsepower Cummins engines are built to deliver their rated power continuously until they are worn out and that might easily be in excess of 10,000 hours. The DKW and the exotic automobile engines that produce 100 horsepower per liter can only produce that power in short bursts just prior to shifting to the next gear. That’s can make for a great deal of fun but for reliable transportation such technology is somewhat of a hindrance.