im not sure about the diamond crimping... ive always seen round ends... what do the recieving seats look like? if they are round, you should have round ends. they could have been deformed during some botched attempts at getting them seated. the tube should stay in place, although its usually a bit off of a perfect alignment during the reinstall...
neither am I sure about what seals you may need for the water intake tube on that motor. ive seen ones that dont use seals, and others that have basic common oring seals..
as for aligning the tube during the install, the older motors had a loose plastic tube around the water tube that could be used as an extension to help in the alignment during reassembly.... pull the plastic out past the end of the water tube and while holding the lower unit in position, place the plastic tube over the recieving port, and as you shove the lower unit into place with the water tube going up the plastic tube towards its seat, the plastic tube will slide back onto the water tube and remain there until needed next time.
