85 I don't think that the Yanmar 4JHE was produced in 85. Looks like the production date states in 1999. It replaced the JH2 from what I am seeing. Anyway TOAD Marine has a complete listing of parts for Yanmar Engines. Good luck!
TOAD Marine Supply - Formerly Torresen Marine online store offers a complete line of sailboat engine parts, hardware, boat parts and supplies for the boating enthusiasts. One source for all of your marine engine parts, sales and service.
Yes, injectors can be tested and rebuilt if necessary. You should be able to find a rebuilding shop in any metropolitan area. If you are having trouble go to your garage or truck repair facility and ask them where to bring them. When I had the injectors tested for my Westerbeke, testing and rebuilding cost 1/2 of what Westerbeke wanted for one injector.