Bleeding fuel system, what am I doing wrong?

[hunt4570]

Kubota 3540 diesel.. Ok, my manual sats when I need to bleed the fuel system, I need to open the breather valve on the fuel pump, start the tractor and let it run about 30 seconds then shut the air release valve. So I do exactly that and it will run for about 30 seconds or so and then die, and I have a hard time getting it going again. WHAT THE HECK am I doing wrong?? thanks. Its out in my drive right now recharging the battery! :-(

 

[Tx Jim]

Check to be sure fuel tank is venting IE vent not clogged

 

[hunt4570]

Check to be sure fuel tank is venting IE vent not clogged

Just had the cap off to add fuel, and it was running fine till I bled the fuel system, so I'm thinking that is not the problem.

 

[Harry in Ky]

Okay, that's not working for you. Try this. Put the manual away. Bleed the filter firsts then bleed at the thumbscrew (or bleed vent valve) on the injection pump as you have been. Crank until fuel looks solid at the bleed screw, tighten it down and leave it alone. Have you been loosening inject lines at the injectors when doing this or just cranking it until it finally starts? Sometimes either method will work. I think it's usually easier on the battery and starter to crack the lines. Your choice, a judgement call. Once it starts don't fool with the bleed screw again. Just let it run and see what happens.

Next question. Does the fuel filter bowl stay full while it's running? Sometimes engines with a supply pump between the filter and the injection pump can develop a problem with that. Not always, but it happens.

 

[Mike1955]

Okay, that's not working for you. Try this. Put the manual away. Bleed the filter firsts then bleed at the thumbscrew (or bleed vent valve) on the injection pump as you have been. Crank until fuel looks solid at the bleed screw, tighten it down and leave it alone. Have you been loosening inject lines at the injectors when doing this or just cranking it until it finally starts? Sometimes either method will work. I think it's usually easier on the battery and starter to crack the lines. Your choice, a judgement call. Once it starts don't fool with the bleed screw again. Just let it run and see what happens.

Next question. Does the fuel filter bowl stay full while it's running? Sometimes engines with a supply pump between the filter and the injection pump can develop a problem with that. Not always, but it happens.

And Harry if some of the injectors are difficult to access I just crack the reachable one. I let it go ahead and start and tighten it up while running

 

[Harry in Ky]

I guess you can. I don't do it that way, but it does work. I usually crack the easiest ones I can get to. It isn't usually necessary to crack them all, it just helps a little if you can.

 

[hunt4570]

Thanks for the help guys, So here is exactly what has happened this time around. Been using the tractor and it was working fine. But the other day I noticed a large O-ring on the ground and immediately thought the filter cup, I had been working on it in this place a few weeks ago and apparently some idiot (me) did not put the O-ring on. Pulled the side cover off the tractor and sure enough the area was damp. Turned off the fuel petcock, took the filter apart and replaced the ring and re-assembled it. opened the petcock and the filter bowl filled up , opened the air bleed valve, started the tractor, waited 30 ish seconds, turned off the tractor, closed the valve and restarted the tractor, ran a bit and then died!! Now it won't restart!!! No pop or anything, just spins!! Was running great till I messed with the filter! My plan is to go out and take the fuel filter apart again and start from scratch!
I'm at a loss right now!!
And yes the filter bowl stays full while running.