Diesel question

Not motorsports related but... I bought a John Deere f935 last year. PO had a problem with the pickup tube to was running off of a bottle  (no, not kidding) Ran fine. So, I properly repaired,  ie installed oe, overpriced JD parts in the twin tanks. Had to reroute the entire fuel system. Anyway, new fuel, pump running, bled to injectors. It will occasionally catch, but no fire. I've bled injectors many times, unfortunately.  Should start. I'm afraid to use starter fluid on a diesel. Any rate, any ideas?

If it has fuel and compression, then it just needs air. Any restriction on the air side? Is it possible you timed the new pump incorrectly?

I didn't replace the pump. Tge air hose is wide open as that part of the bodywork is still off from doing all the fuel related work.  The joy of twin tanks.

I used to use ether on my 84 f250 diesel all the time (when the glow plugs were non functional, do not use it with functioning glow plugs).

Maybe the issue wasn't the pickup tubes and is something you haven't replaced?

Some diesels can do ether just fine, others will kick back and could cause damage.  Because the "ignition" is the injector timing, introducing HC in the intake air can cause it to pre-ignite.  I've seen starters bolt bosses ripped off of blocks from this.  Totally depends on the diesel, and I'm not well versed on that aspect with JDs.  Ether is a good way to introduce heat for a diesel that won't light off, but if you have air bubbles, you're just running on ether and it won't help the fact that diesel isn't getting there.  I suppose it's possible that a few seconds of running on something might jiggle some of the injectors open?  Short version:  Make sure you know that ether is OK in your specific engine.

Bled to injectors sometimes isn't enough on mechanical injection.  Depending on how things are plumbed and how each injector is shaped internally, it can be nearly impossible to get all the air out.  It doesn't take much of an air bubble for the injectors to not pop open.  Does it have a manual pump that you're supposed to operate?  Some have a lever or plunger that you have to press.  If it does, do that until your arm is sore.

I can only add a little to what Curtis has said.  If it has a pre chamber do not use ether.   
    Try to get the engine as hot as possible.  Electric heaters with a shroud or blankets trapping the heat. ( careful not to set the blankets on fire). 
         Try heating the diesel fuel.  I've used a propane torch on the fuel lines.  These tricks are not just for winter.  If the rings are worn or just not sealing heat is your friend even on hot days. 

Update. I thoroughly cleaned the entire state and thought I had it fixed. The deck managed to show its weakness so I had to tear it apart and a ton of welding. That's done and finally back to my 4' tall lawn. Yes 4 feet! Same damn problem. Can get it to run for more than 5 minutes! This system uses, from the factory,  an electric pump. No priming pump. Tank to hose to electric pump to filter to mechanical distributor to injectors. When it's running properly,  it's running on all 3 cylinders. 

Fuel pressure gauge? That would tell a whole lot about what's going on, because diesels are really really simple in operation. Are the injectors mechanical or electrical, because that's a whole 'nother potential issue.

If it consistently runs for some time and then quits, it could be heat-related, or something like it drawing a vacuum in the fuel tank, maybe.

Worst case would be damaged rings and compression so low that it has trouble compressing the mix enough to combust. Let's pretend it's not that.

Injectors are mechanical. Yanmar 3TNA72

In reply to kb58 :

Has plenty of power. This is definitely fuel related. Isn't running long enough to get really hot

Does it consistently quit after some amount of time? If yes, get it running and a minute before it tends to quit, remove the fuel tank cap.

When it's running, is that at idle or in active use?

It stalls out while I'm using it to mow.

Are you thinking vacuum issue with the tank?

People are suggesting its an issue with tank venting, basically the vent on the gas cap is clogged and at some point the draw from the pump can no longer compensate for the vacuum in the fuel tank.

FWIW, when it finally starts after stalling, it will usually only idle roughly and can take a few minutes to come up to full power

In reply to 93gsxturbo :

I took off the caps as this was happening, no change. I haven't checked the vents in the caps but, they are certainly the original ones so over 20 tears old.

Is the return line to the tank free flowing? Is there a check valve on the injector pump for the return line?

If the return line is restricted or blocked it can lead to issues with shutting down and hard starting one pressure builds up.

I'd look for a check valve in the fitting for the return line on the injector pump and make sure it's free. I'd also check the line to the tank to make sure it doesn't have any restriction or blockage.

You could try running a line from the return fitting on the injector pump to a container so you can fire it up and see if there is flow and also if that avoids the stalling out.  

This system doesn't have a return line. However, when she was about to stall out, I turned off the pto and tried to turn her off, stayed running.  The previous owner set it up with a fuel pump switch and a start button,  no idea why. And the glow plug light remains on. Not sure how the fuel is cut off to stop it but I think it's a solenoid 

It's an electric shut off solenoid, so not likely part of the problem 

I'm ordering a solenoid as the boot on this one is torn

Docwemple said:

This system doesn't have a return line. However, when she was about to stall out, I turned off the pto and tried to turn her off, stayed running.  The previous owner set it up with a fuel pump switch and a start button,  no idea why. And the glow plug light remains on. Not sure how the fuel is cut off to stop it but I think it's a solenoid 

I was curious how they avoided a return line and the return runs back to the fuel filter, so it never makes it back to the tank. It should be the line crossing all three injectors (Figure 12).

It sounds like you've narrowed it down to something electrical, so the return line is ruled out. 

In reply to No Time :

My bad. It's set up like my IDI. There are small lines between the injectors that must act like a return  so I'm going to replace those