My Zen 2 is almost 11 lbs and the 140rx has plenty of power left over. I'm running a 15.5x2 4 blade on it. Awesome power. Way more than my ys140L. It also has great power with the 17x13.
I generally agree with what you say Mike but not on the under 11 lb thing. Maybe yours wasn't running right or something. They compare to the ys dz's by far. Perfect motor for pattern. Easy to run. Never have to touch it.