Oil & Fuel NH LS125 problems after running out of fuel

[Tom Brown]

I ran my LS125 skid steer out of fuel. It is a 3 cylinder diesel with 16.5 net hp. I understand it is pretty much identical to it's ag brother.

Anyway, I ran it out of fuel. I added fuel and tried to prime it. It's tough to prime without having another person there but I managed to get it running again at idle. It wouldn't rev so I let it idle for 15~20 minutes.

After some idling, I opened the throttle. It came up to operating RPM nicely but only for 5~10 seconds and then went back down to idle. If I leave the throttle open, it will rev up to operating RPM (or sometimes not quite) for a few seconds and then return to idle. It will do this every 30 seconds to a minute, or so.

I've checked the air and fuel filters. Both look new. I blew out the air cleaner and I can blow through the fuel filter easily.

It sounds like a fuel pump to me since it idles so nicely. Is there anything else I should check?

I've got a service manual on order but I need the machine to run in the next day or two and the manual will be over a week getting here.

 

[dqdave1]

I would replace the fuel filter; when you have fuel filter off, open tank shutoff valve and make sure you have good flow, if not blow back through line to tank to clear restriction. Rebleed injector pump after changing fuel filter. You may have to bleed each line at the injectors. ( Beware of high pressure at injectors)

 

[rambler]

Can be difficult to get things bled right, some designs are auto-bleed; some don't bleed out very well at all! I'd suspect some air in there somewhere yet.

Otherwise, dirt in the filter or line, restricting flow.

--->Paul

 

[Tom Brown]

Thanks, gents.

I just finished changing the filter and blowing out the lines. With the stop cock open, fuel will flow into a pop bottle at the pump end of the hose at a pretty good rate. I'd guess 1/4 cup per hour.

It still doesn't like to go much above idle. It will surge to higher RPM here and there but it won't stay there.

Just for kicks, I took the fuel cap off, placed my hand over the filler, and put the air nozzle between my fingers. With a squirt of air, the engine will rev hard. Is that a clear sign of fuel pump problems?

 

[rambler]

Thanks, gents.

I just finished changing the filter and blowing out the lines. With the stop cock open, fuel will flow into a pop bottle at the pump end of the hose at a pretty good rate. I'd guess 1/4 cup per hour.

It still doesn't like to go much above idle. It will surge to higher RPM here and there but it won't stay there.

Just for kicks, I took the fuel cap off, placed my hand over the filler, and put the air nozzle between my fingers. With a squirt of air, the engine will rev hard. Is that a clear sign of fuel pump problems?

I think you meant per minute, not per hour? 1/4 cup per minute would be pretty slow flow. Should do better than that.

I am not a diesel mechanic, so I don't _know_, but I am very troubled that you keep adding high-pressure air into your injector pump. I think perhaps now you do have a pump problem. Those are very, very fussy items with very tight & fussy tolerances. Putting air into them repeatedly can't be good. Again, I'm not a diesel pro, so I can be wrong on this, but I think that is a real bad thing to do.

At the least, you keep adding air to your fuel system. What you want to do is work the air out of the system, not keep adding air. When I ran my big Ford out of fuel, it took a mile of driving on the field roads before the engine really caught on again & got all the air worked out.

If it were me, I'd only be blowing air back into the tank; not into the injector pump.

--->Paul