This report describes the engineering challenges in the development of 4 stroke 50ps outboard motor. The goal was set to attain the top speed and acceleration performance comparable to the existing 2 stroke versions, while providing the advantages of 4 stroke engine, including the alleviated exhaust odor and operational noise, as well as consistent performance with stable rpm. Emphasis was also given to the trolling at low rpm (at 650rpm). Our engineering challenges have been embodied into the 4 stroke outboard motor which is “clean” and yet allows similar application as existing 2 stroke versions.
