Help with a L4630 WSM issue (and tractor stalling issue)

[Derf]

My L4630 GST is a used one I bought from my neighbor a couple of years ago. It has been very reliable, but I decided to replace the fuel filter based on the hours I had used it. I used this image from the workshop manual for bleeding after I finished, but the fuel cock (see inset image) on mine can swivel from "A" to 180 degrees (90 degrees past the vertical line in the image). The inset image seems to indicate that the vertical line means something, but there's no "B" location for open, like there is on the air vent cock. Also the arrow for the fuel cock is pointing from the vertical line toward the "A", despite the text indicating that the fuel cock needs to be "open" and the description says "A" is "closed".

So, can anyone explain what position should be used for the fuel cock while bleeding, and what position do I leave it in when I'm done bleeding?

 

[North Idaho Wolfman]

Sorry but your getting a little confused, the WSM can do that.

The Fuel Cock on the filter housing flag should be sideways (A position) to shut off fuel flow when you change the filter, then opened to the #1 position when it's in run mode.


The Air vent on the side of the injection pump will turn mutiple times, just turn it counter clockwise ( B direction) like one turn to bleed the air out of the line and pump, then turn it clockwise (A direction) to close the valve.

 

[Derf]

Sorry but your getting a little confused, the WSM can do that.

The Fuel Cock on the filter housing flag should be sideways (A position) to shut off fuel flow when you change the filter, then opened to the #1 position when it's in run mode.
View attachment 176463

That's what I was thinking, so I seem to be doing the right thing. What happens when I turn the fuel cock the opposite way from "A"?

Also, if I try to start and run the tractor with it in "A" position, shouldn't it either not start or not keep running, since it is cutting off fuel going into the filter?

The Air vent on the side of the injection pump will turn mutiple times, just turn it counter clockwise ( B direction) like one turn to bleed the air out of the line and pump, then turn it clockwise (A direction) to close the valve.

View attachment 176464

So I've done this a few times now, leaving the engine running 30 seconds up to over a minute, and it still stalls after just a couple feet of forward movement (reverse seems to go a little farther). I would guess that either means it's not a bleeding problem or the valves aren't doing what they are supposed to. I saw a post from someone that they had installed their fuel filter upside down. Maybe I ought to check that.

 

[North Idaho Wolfman]

That's what I was thinking, so I seem to be doing the right thing. What happens when I turn the fuel cock the opposite way from "A"?

Also, if I try to start and run the tractor with it in "A" position, shouldn't it either not start or not keep running, since it is cutting off fuel going into the filter?


So I've done this a few times now, leaving the engine running 30 seconds up to over a minute, and it still stalls after just a couple feet of forward movement (reverse seems to go a little farther). I would guess that either means it's not a bleeding problem or the valves aren't doing what they are supposed to. I saw a post from someone that they had installed their fuel filter upside down. Maybe I ought to check that.

Take the output hose off of the filter housing and see if there is good continuous flow coming out of it.
These style of filter housings have been know to clog up the intake side of the filter housing.



If you have good continuous flow out of the housing, move up the chain.
Go to the output of the lift pump.


Remove the line at the injection pump input and put it into a container.
Start the tractor ( it will run for quite a while on the fuel in the injection pump housing) and look for pulses of fuel out of that line.



No pulses of fuel bad lift pump, pulses of fuel good pump.

If that is good then your chances of it being a fuel supply issue are low.

 

[Russell King]

@North Idaho Wolfman
Is there any possibility that the air vent being open (even if you think it is closed) could cause the issue?

I seem to recall someone having a running issue and finally figured out that the air bleed was open but may be recalling it incorrectly.

 

[North Idaho Wolfman]

@North Idaho Wolfman
Is there any possibility that the air vent being open (even if you think it is closed) could cause the issue?

I seem to recall someone having a running issue and finally figured out that the air bleed was open but may be recalling it incorrectly.

It can, but usually you'll only notice it when the the lift pump is bad, as it normally will move more diesel than the tractor uses.
Easy to test, just pull off the vent line, if diesel comes out off the shut off when it closed, it's bad.

 

[whitetiger]

Also, see if the hose barb fittings are tight in the filter head. If they become loose, you will suck air around them.

 

[Derf]

Take the output hose off of the filter housing and see if there is good continuous flow coming out of it.
These style of filter housings have been know to clog up the intake side of the filter housing.

View attachment 176476

If you have good continuous flow out of the housing, move up the chain.
Go to the output of the lift pump.


Remove the line at the injection pump input and put it into a container.
Start the tractor ( it will run for quite a while on the fuel in the injection pump housing) and look for pulses of fuel out of that line.

View attachment 176477

No pulses of fuel bad lift pump, pulses of fuel good pump.

If that is good then your chances of it being a fuel supply issue are low.

After not having time to work on this for a few days, I went out to try your troubleshooting steps this evening, but a couple of things occurred to me.
1. That if it is a fuel delivery problem like you have described, it would eventually show up even without putting the tractor in gear and trying to drive it, wouldn't it? Especially if I raced the engine a bit?
2. That I should be able to shut off the fuel flow (to see how the tractor responds) by shutting off the fuel cock. Is that correct? Does the fuel cock shut off fuel to the engine such that it will quit eventually from fuel starvation? How long should I have to run it?
I actually tried running it with the fuel cock closed (A position on the drawing), and it behaved the same way--it died when I put it in gear and tried to move, but not before. And it started back up again with no problem, which makes me fairly confident that it isn't that the fuel isn't there, but something else. The fuel cock being closed and the tractor still running doesn't make sense to me unless the fuel cock isn't really doing what it's supposed to do.

So I tried lifting the seat and checking the safety switch (ignoring the fuel cock issue for a bit). After putting the seat back down, I started it up and it ran just fine. You'll remember that you helped me with another engine shut off issue while using PTO outside the cab, suggesting that the seat switch might be making the engine shut off because the seat's down, but there was some delay before the safety kicked in. I'm thinking, since it's the same component, maybe the seat switch it faulty in more than one way, and it was shutting down the engine while it was in gear, thinking I wasn't in the seat (but with a little delay). I'll have to see about swapping out that seat switch.

Back to the fuel cock. All of the above paragraph happened with the fuel cock in the "off" (A) position. Is the fuel cock supposed to shut off the fuel supply to the engine completely? If so, why is it not doing what it is supposed to do?

Any thoughts are appreciated.

 

[North Idaho Wolfman]

The fuel shut off is not instantaneous, the fuel injection pump holds quite a bit of reserve fuel.
I can run mine for quite some time before it finally runs out of fuel.

If you want to know it it's working or not, simply pull off the fuel outlet hose and see if fuel stops when you shut off the valve.
Also you said you changed the filters, if it didn't shut off then fuel would have been pouring out, but note if the fuel inlet, or valve is clogged that will stop the fuel regardless of the fuel shut off position.

I personally would follow what I previously wrote as that would put the fuel delivery to bed once and for all, then you could go on to other possible issues.

 

[Derf]

The fuel shut off is not instantaneous, the fuel injection pump holds quite a bit of reserve fuel.
I can run mine for quite some time before it finally runs out of fuel.

If you want to know it it's working or not, simply pull off the fuel outlet hose and see if fuel stops when you shut off the valve.
Also you said you changed the filters, if it didn't shut off then fuel would have been pouring out, but note if the fuel inlet, or valve is clogged that will stop the fuel regardless of the fuel shut off position.

I personally would follow what I previously wrote as that would put the fuel delivery to bed once and for all, then you could go on to other possible issues.

It did finally die from fuel starvation today, so I turned the fuel cock back on. Took a few tries to get it started after that, but then it ran fine all day. I'm still thinking it was the somewhat unreliable seat switch.

Has anyone on here ever taken one of those apart? In my past life as an engineer (not mechanical or electrical, but I still like to fiddle with stuff) we had an issue where a high voltage switch would stick on or off because of the arcing taking place while the switch was pulling away from the contact or traveling towards the contact--it made the switch contacts bumpy, giving it a kind of velcro-like texture (under a microscope) that would catch (not allow the switch to open) or hold it open (keeping the contacts separate). We didn't have access to the switches to do anything with them, but I could imagine sanding the surfaces back to smooth if I could open the switch and see the contacts.