hmmmmmmmmm!
Welcome to the Seadoo forum....
I've waited long enough and noticed that there hasn't been any input as to the better of the two.........well, let me give you my biased opinion!
The BRP Rotax engine was first developed in 1920 at it's plant in Dresden, Germany. In 1943 they moved their operations to Wels, Austria. Since their inception, the Rotax engine corporation has developed over 350 engine types and manafactured over 5 million engines for use in the snowmobile, motorcycle (BMW's), PWC's, boats, and even aircraft industry. I know my opinion of which is better would be considered bias, because I own one and have a mechanical apptitude for the overhaul and repair of this engine.
But in fairness I ask you.....how long has the Yamaha engine been in development?.........oh, never mind. It's only been in development and on the market for 50 years........so by research and development alone, Rotax would be the better of the two. :hurray:
O.K., I've said it..........and I stand by what I wrote.
BTW, this information was researched from the Rotax and Yamaha engine websites. :cheers: