Here's the diagram for a Merc (may help see the breakdown, couldn't find Honda), usually you can buy the seal repair kit. The end cap is expensive, on the Merc's it always used to be the scraper that failed detaching from the end cap.
Not sure with Honda's common faults though
Peter @ Boatsandoutboards4sale ~ www.BoatsandOutboards4Sale.co.uk
~ 07930 421007