I'd suggest having a chat with
marine mechanics in your area. Get some idea of how good they are, how available and how much they charge.
On the iceberg theory your injector pipe may represent 10% of the
work needed on your
engine. You need to find out what can be kept going, what must be fixed and to
work out a
maintenance plan.
If you do get a
mechanic get him/her to show you how to change the
oil (gearbox and engine), filters (fuel, air,
oil and raw water) and
raw water impeller. If you can find spares for these (they may be on the
boat already) even better.
A good
mechanic could also make suggestions to improve
reliability (like adding a primary filter for instance).