Yanmar Injection Nozzle Testing

jdp2011 · May 20, 2015

I am rebuilding my injection nozzles from my JD 4400. Thought I would share some pictures.

The pic showing the spray pattern look close there are actually 5 spray jets. most other yanmar nozzles only have four. I beleave this was done to meet newer emission standards at the time 2001.

jdp2011 · May 20, 2015

FYI these same injectors are used in JD models - 4200-4700, 4210-4710, 855,955,FM mowers etc pretty much any JD with a Yanmar from 1990-2000+ used this stye injector they may have different tips but that would be the only difference the body and internals would be the same. This injector is for the direct injected engines.

beenthere · May 20, 2015

Interesting, but maybe you would share a bit more about what you are doing and how/why. I don't see a pic showing a spray pattern, but do see pics with various arrangements of the nozzle (in parts as well as hooked to an apparatus). Other than that, no idea but am interested.

Fawken · May 21, 2015

I've got that same pop tester. I would think (unless your hours are way high) the nozzles just need cleaning on such a new machine. I use a toothpick in a drill with carb cleaner. If they're bad though and after a good cleaning they don't spray or don't pop at the rated pressure, I just buy new nozzles and test them in your existing injector housings. You might have to look up a ND or Hatzan cross reference to get a good price. I pay $15-$22 a piece at finditparts.com

jdp2011 · May 21, 2015

beenthere said:
Interesting, but maybe you would share a bit more about what you are doing and how/why. I don't see a pic showing a spray pattern, but do see pics with various arrangements of the nozzle (in parts as well as hooked to an apparatus). Other than that, no idea but am interested.

To clarify I am replacing the injector tips on my current injectors, Setting the pop off pressure and check for chatter and spray pattern. I refer to this as rebuilding the injector.

The first photo in the attachment box shows the spray pattern- very difficult to get the timing right with the flash and when the injector pops to get a clear photo of the spray pattern

jdp2011 · May 21, 2015

Fawken said:
I've got that same pop tester. I would think (unless your hours are way high) the nozzles just need cleaning on such a new machine. I use a toothpick in a drill with carb cleaner. If they're bad though and after a good cleaning they don't spray or don't pop at the rated pressure, I just buy new nozzles and test them in your existing injector housings. You might have to look up a ND or Hatzan cross reference to get a good price. I pay $15-$22 a piece at finditparts.com

I will respectfully disagree with you. I have seen these yanmars with as low of 200 hrs- and one or more of the injector nozzles ether not spray correct or partially plugged up or no chatter sound.

Idling these motors and not putting them under a good load to keep them cleared out cause plugged up injectors.

I do have cleaning wires for the tips but most of the time they have to be replaced.