Paul,
First you will have to raise the trailer axle slightly, and be on fairly flat ground. Pulling the trailer up on a couple of 2X4's should work as it only needs to be about 2" higher. Being on an inclined drive as long as it's flat is OK too.
Using a carpenters level held on the pad, level the boat surface using the trailer jack.
Next, lower the motor, and using the carpenters level on the cavitation plate, level the motor (the reason for raising the trailer is to let the skeg clear the ground with the motor in the level position).
Now the motor is in the same plane as the pad. Measure the distance from the ground to the pad and from the ground to the center of the shaft or the cavitation plate. The cavitation plate is exactly 8 inches above the prop shaft.
For the 882 the optimum position is the prop shaft 3 inches below the pad (this puts the cavitation plate 5 inches above the pad).
For the 150, the motor should use the lower of the 5 motor mount holes in the lower of the 2 mounting holes in the fatcory set back plate.
This setup has also been confirmed by the Richard at the Nitro test facility.
After a lot of testing with a CMC hydraulic plate and various props (About $1,500), I found the factory position (with 23 Tempest) described above to be the optimum.
If it ain't broke, don't fix it!!!!
Russ
