fine tunning K&B outboard high RPM
 

Ok you guys have to be sick of my questions. I've bought a few books on nitro but their all old. What or how is the best way to fine tune my boat for speed and HIGH RPM. I want to beable to throw a big rooster tail but also go fast. I have a newer K&B 3.5 outboard motor, right now I'm running 40% nitro and I was thinking about running 50% and a hoter glow plug. Oh and I'm using a Octura 440 prop on my 30inch tunnel hull. I just ordered a bullet lower unit and a cooper tuned pipe.

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.

RE: fine tunning K&B outboard high RPM
 

I couldn't pull up the link you left.

RE: fine tunning K&B outboard high RPM
 

Try it again, when it was first posted out, link wasn't right. If not, check out the links on this [link=http://home.earthlink.net/~ob_nut2/id15.html]3.5 Tunnels[/link]

RE: fine tunning K&B outboard high RPM
 

Got it. well besides speed how could I make it through a big rooster tail?

RE: fine tunning K&B outboard high RPM
 

Are you talking about another boats roost? If so, then pray or stay away from it. Some people have put air filters used for cars/trucks on their motors. Don't know how much that would help. Filters won't stop water 100%.

RE: fine tunning K&B outboard high RPM
 

I think the word that he wants is throw, not through.
The cavitation plate is what is keeping the engine from tossing a big 'tail. A roostertail isn't everything. If you've ever seen a FAST boat run, their roostertail comes out flat. A high roostertail comes from a prop that is too high. Compare it to smoking your tires, it looks cool but you're not going anywhere.

RE: fine tunning K&B outboard high RPM
 

It does? :)

RE: fine tunning K&B outboard high RPM
 

What are todays options for outboard pipe setups for KB 3.5SS?

RE: fine tunning K&B outboard high RPM
 

For information on the Silver Bullit 3.5 Pipe, go to htbboats.com

JD
AquaCraft Models