I just did 2 of these motors. If you haven't bought your seals and gaskets yet, John Zigler has the best deal going on sets. I think he's on this fourm, and definitely on PWCToday and GreenHulk.net.
I used 1204 or 1104? can't remember, bought it at the Honda shop.
Definitely take the time to pressure test the motor before you put it back in the ski. I found a major air leak on one of mine, and had to tighten up the crankcase bolts just a touch to eliminate it. Pressure testing is easy to do, you just need a decent tire pressure gauge, some fittings from NAPA, and a blockoff plate or 2. I made mine out of some scrap aluminum sheet (ex Stop Sign!)
Put in a primer kit if you don't have one already. Zig sells them too, best pricing also.