Yanmar 1700 injector insulators and injector cavity nozzle questions

[goose117]

Hello - new to this forum. I have a Yanmar 1700. It ran pretty well for 20 years, then stopped starting. Over the last few years I've slowly replaced many parts - injectors, injection pump, head (old one was leaking water into the cylinders), pistons, sleeves. With many attempts I can get the tractor to start and it runs but has little power. I checked compression and have 600 psi and 550 psi readings for the two cylinders.

I took the injectors out to do the compression tests and noticed the injector insulators seemed 'burnt '. Also the holes in the injector cavity nozzles have been enlarged quite a bit. Please see the photos.

Any thoughts on what is causing these results or what to do with replacements to avoid this? These parts have had only an hour or so of run time on them (new parts from the rebuild and only 4 or 5 10-15 minute runs).

I'm wondering if part of the problem is injection timing being off or perhaps combustion happening inside the nozzle as well as in the cylinder?

Thanks for any thoughts on this.

 

[thepumpguysc]

It very well could be timing..
The enlarged hole is from the spray pattern being off..
Are u torquing the injectors down or just using a wrench.?

 

[bmaverick]

Hello - new to this forum. I have a Yanmar 1700. It ran pretty well for 20 years, then stopped starting. Over the last few years I've slowly replaced many parts - injectors, injection pump, head (old one was leaking water into the cylinders), pistons, sleeves. With many attempts I can get the tractor to start and it runs but has little power. I checked compression and have 600 psi and 550 psi readings for the two cylinders.

I took the injectors out to do the compression tests and noticed the injector insulators seemed 'burnt '. Also the holes in the injector cavity nozzles have been enlarged quite a bit. Please see the photos.

Any thoughts on what is causing these results or what to do with replacements to avoid this? These parts have had only an hour or so of run time on them (new parts from the rebuild and only 4 or 5 10-15 minute runs).

I'm wondering if part of the problem is injection timing being off or perhaps combustion happening inside the nozzle as well as in the cylinder?

Thanks for any thoughts on this.

The experts to your questions are in the Yanmar vintage section.

Yanmar

Discuss classic and grey market Yanmar tractors and equipment!

www.tractorbynet.com

 

[Barry 1]

I see the lower chamber and the injector.Where is the upper chamber? The piece that goes in between those 2. Part # ic-1141

 

[careyo63]

This is a Hoye Dia. YM2000/1700 Fredricks part's says Injector IC-4450 Inj. chamber, Front Inj. rear IC-1141 And the GW-4900 Chamber gasket. I'd call Fredricks for the Yanmar Parts. The Ym2000 they refurbish that model so they know it well.

Attachments

• 
  Injector.jpg

  67.7 KB · Views: 63

 

[goose117]

Thanks for the replies!

I have taken the injectors out several times. I can see how the spray pattern being off might cause the forward chamber holes to grow if the combustion is not happening where it is supposed to be. Would this likely have a big effect on starting?

If it is a timing issue (driving the hard starting), is it likely fixed by the timing associated with the governor linkage, the injector pump shims, or both? I have gone through the process of trying to check those before but am not positive I have this right yet - especially since my injector pump does not have the little detente mark I've seen used for setting the governor linkage and timing adjustment screw at the forward end of the block.

I usually just tighten the nuts on the injectors but have done it with a torque wrench a few times - but not recently. I'll go back to the torque wrench when I install my new parts. From the manual it looks like the torque for these fuel injection valve nozzle holder body nuts is 65-80 ft lbs?

I can try to check the spray pattern too. In the past they didn't seem obviously bad to me but I should check again.


Thanks for the pointer to the yanmar vintage tractor forum. Should I repost there?


I didn't include a photo of the rear chamber because it seemed relatively normal - just some of the residue shown on the bottom of the injector sticking to that face that is next to the injector.

I have new forward chambers, teflon insulators, and the copper packing/gasket you've listed.

Thanks again.

 

[goose117]

Added some pictures of the injector spray patterns.

 

[thepumpguysc]

That looks to be a little “streamy” rather that atomized..??
Are u checking them with a pop tester or with the injection pump.??
If it’s with a pop tester, when u go slow, does it go pop, pop, pop.??

 

[goose117]

They are fed by the injector pump. I thought they didn't seem very atomized but these are basically new injectors. They have been exposed to water a few times though before I replaced the head which seemed to have a crack - at least I'm not getting water in the cylinders with the new head. They do seem to fire reliably with those same shapes from the several seconds of video I have.