RE: fine tunning K&B outboard high RPM
If speed is what you are after, the "tall roostertail" won't be there. Check out a vid of a 30" WOF, MAC .21, Lawless lower, Garcia pipe and a S215 - [link=http://www.rcflix.com/photopost/data/506/612Queen_City_Race_Heat_5_2.mpg]Vid[/link] There's more speed to be had, just working on it. If you can, get 60% or higher nitro for the motor. Plug would be either a K&B L1 or MC9. The x440 prop is now on my boat, which is close to the S215.
As stated before - needle tuning. After starting the motor, blip the throttle wide open from idle. What does it do?
Revs sky high - too lean
Bogs a bit, clears out - in the ball park
Bogs, never clears up - too rich
K&B 3.5 needle should be around 3 1/2 turns out. Turn it about 1/8 of a turn each time. It'll most likely end up around 3 turns out.