If I'm not mistaken, the ASP .91 is identical to the Magnum .91 FSR. From the picture, I'd say they're virtually identical. Chances are there's nothing you need to do to the engine other than prime it, run it, and adjust it as you would any other engine. My experience with the Magnum 91 is that a 14x6 APC prop is just about perfect. You want to prop it to turn in the 9000-10000 RPM range.

If its a ringed engine, and I think it is, you want to run fuel with some castor in it to help seat and seal the ring. Don't run it blubbering rich. Also don't run it up to full throttle as soon as it starts, as you want to give it a chance to warm up (unlike ABC or ABN engines that you want to heat up quickly). After a few runs you might want to take off the valve cover and check the valve lash (get yourself a good feeler guage).

You'll want to use and electric starter until you get it broken in a tuned. After that, chances are you'll be able to start it with a quick backflip against compression.

You might find that this is too much engine for a U-Can-Do 46.

Brad