I just read your latest IW post....After our conversation I was amazed that all you got out of it was the rudder....
The rudder will help with fine tuning but you are not addressing your basic problem ......That hyperformance bullet extending out in front of the lower end
and removal of the ski is killing your setup....
I sent you a very detailed email at 3AM this morning..... Unless you are willing to get rid of that lower and reinstall the ski I am
afraid you are destined to be unhappy with your JAE outboard..... As long as you are dragging that lower bullet mess through the water
and attempting to hold the rear of the boat up with the prop you are effectively chasing your tail and neutering the JAE's design....
You may be able to cut off the front of the hyperformance lower to a K&B/O.S. lead in contour and depth and accomplish what you need to do to run the ski....
My suggestion is get your hands on a K&B 3.5 lower , install a side mounted rudder , re-install the ski and mount and setup the outboard like shown in the instruction manual....
There are photos on page 34 of the manual showing what you need to do......
http://www.zippkits.com/21obman.pdf
IF you do this and the boat still pulls left or right look at the turn fin adjustment and then the width/depth of the rudder "THE SKI IS NOT YOUR PROBLEM"....
Everything touching or below the water is what counts for a happy boat.....Everything above is mostly eye candy.....
Maybe somebody else has a better way to convince you what you need to do to take advantage of the JAE's design....I don't know what else to do....
I offered access to a K&B lower in my detailed email and that offer is still in play..... just let me know what you would like to do.....
With the power you have available that boat should be all over 80 MPH.....