Yamaha two stroke Waverunner engines are bona-fide marine engines. They have little in common with a bike motor. Synthetic two stroke oil and a properly adjusted injection pump or accurately premixed gas can burn with little smoke and fumes. They are tough and durable too. I have a 1990 model Waverunner III (650 cc.) with a ton of run time in both fresh and salt water and it still goes good. Of course, if I had someone else's checkbook to use at the marina, I'd go for a new four stroke in a minute.
