If your question is about how to bleed, here is from the Yanmar manuel:
http://www.boatinfo.no/lib/yanmar/manuals/jh4.html#/56
1. Check the fuel level in the fuel tank. Refill if necessary.
2. Open the fuel cock of the fuel tank.
3. Loosen the air bleed screw
(Figure 5, (2)) 2 - 3 turns.
4. Push up and down on the priming pump
(Figure 5, (1)) to release air out of the air bleed screw.
Continue pumping until a solid stream of fuel with no air bubbles begins to flow
5. Continue pumping until a solid stream of fuel with no air bubbles begins to flow.
6. Tighten the air bleed screw.
* air bleed screw is on the top of the injector pump.
Go to page 41 of the manuel on the webpage I just gave you for diagrams and LOTS of details.
Some Yanmars have self bleeding, I believe that the 4JH4E does. You do have to bleed after introducing air (for example when changing filters). Some of the times I have changed filters, I did not need to bleed. Last time I did. Probably because I took the Raycore filter apart to clean it thoroughly.
I agree with Terry. My 4JH3E (very similar engine) is a remarkable engine.