I think you guys are looking for too much from this engine. I have a Q42 which is the forerunner of the US41 and the best I could ever do is 6900 on an 18 - 10 prop, I have a Brison 2.4 and it turns the same prop 1000 more rpms. My Q42 has been sitting in a box since 1991, tooooo heavy and toooooo underpowered. A US41 rippin' and roarin' ? In your dreams maybe