RE: Aquacraft Super-Vee 27 Nitro.
1. You need two (2) open ended (or adjustable) wrenches - if you have the correct size open end wrenches, great, otherwise just use the two adjustable wrenches.
2. You adjust/tighten and HOLD the BIG lock bolt/nut that sits VERY HARD & TIGHT next to the flywheel - this is easier for the process if you hold this in a vertical position.
3. With the second/smaller wrench, turn the second smaller bolt/nut in a COUNTER-CLOCKWISE direction (pull backwards on the wrench TOWARDS you). When it/the smaller nut becomes loose enough to turn by hand, you should be able to remove the whole drive spring, shaft, prop, prop nut as one unit.
Now you can do whatever it is that you want: lube or replace the drive spring, etc.
Note: to just change props, you DON'T need to do this whole process - JUST SIMPLY REMOVE THE PROP NUT!
Hope this helps (and this applies for most boats of this type, both nitro AND brushless electric motors).