tilt/trim pump rebuild

[Joe_the_boatman]

Well, finally got the motor running right (first successful lake test was yesterday!) but noticed my trim won't hold position for more than a few minutes. It's always leaked a little oil, too.

So, it looks like there isn't a "kit" to replace all the seals on these, but instead just 4 (or 8) o-rings. Are those the only seals that can get replaced?

Diagram:
http://www.crowleymarine.com/mercury_parts/276/190.cfm