JD X749 Dying after 30-45 minutes

[Egon]

Temperature & electrical components that get hot???

 

[Mike VS]

Neighbor had a Allis WD that would just stop out of the blue. It acted like it ran out of fuel but we would pull the fuel bowl and it had plenty and everything was very clean. Except, one time, while looking in the tank, I saw something different. It was a piece of brass shim stock about 3/4" square. Every once in a while the shim would get close to the outlet and get sucked against it. By the time we would pull the bowl, it had floated away. At least your problem is more consistent.

Yea, it has done this exact routine for a year and a half, and with exception of last week (it went 90 minutes without dying) it has always died between 45 minutes and an hour.

 

[Mike VS]

Temperature & electrical components that get hot???

Diesel... no electronics except fuel solenoid and it was replaced.

 

[Diggin It]

Thanks... While I appreciate your attempts at curing my woes, that's more headache than I can handle right now but I will say this: Imagine you are cutting the grass at a nice clip when somebody runs up behind you and turns the key off. That's what it SOUNDS like, no coughing or sputtering but I will say this; I have been able to keep it running by being real quick and pulling back the throttle and hitting the PTO switch. Once or twice this kept it going and I was able to wait a minute at idle and then throttle up, but only for a few minutes before it died.
At this point, I will probably fix a temp gravity fuel tank around my neck and watch the strange looks of my neighbors.

You keep arguing against electronics or anything else other than fuel, but this implies differently. If that PTO switch or some other switch, safety or electrical component, wire or connector heats up with time and closes, or opens, it could cause these symptoms.

I'm also wondering about airflow that slowly gets restricted over time.

What I don't understand is how consistent the timing seems to be. Did somebody install a cutoff timer when you weren't looking forcing you to take breaks?

 

[crazyal]

Sorry if you answered this but I can't remember. Does it have a clear fuel filter? If so is it empty when it dies? If not installing one before the fuel pump would confirm that the pump has fuel when it dies.

The only two things that come to mind that were similar to what your experiencing were on my Case backhoe it has an in-line filter along with a canister style filter. The in-line filter is just a metal one that's spliced into the fuel line. It's two halves that has a crimp to hold them together. It's before the fuel pump. The crimp was very lightly rubbing on something and wore a very small hole in it. It was too small for diesel to leak out but it would suck air in. When running it was fine but if I shut it off it would turn over for ever. Without a diesel leak it was very hard to find.

The other issue that comes to mind is a coworker had a similar problem. He had gotten some hay in his fuel tank and it would run fine and then shut off but I thought he said it was after a random amount of time. He had to pull the tank and clean it out.

 

[radios1]

You keep arguing against electronics or anything else other than fuel, but this implies differently. If that PTO switch or some other switch, safety or electrical component, wire or connector heats up with time and closes, or opens, it could cause these symptoms.

I'm also wondering about airflow that slowly gets restricted over time.

What I don't understand is how consistent the timing seems to be. Did somebody install a cutoff timer when you weren't looking forcing you to take breaks?

the fuel cutoff solenoid is the only electrical device that could stop the fuel, that was replaced, and the voltage monitored and the solenoid gets constant power, so it's not an electrical problem..

 

[Diggin It]

the fuel cutoff solenoid is the only electrical device that could stop the fuel, that was replaced, and the voltage monitored and the solenoid gets constant power, so it's not an electrical problem..

And yet he talks about the PTO switch apparently having some effect.

 

[Egon]

Diesel... no electronics except fuel solenoid and it was replaced.

No safety shut offs or such items?

 

[ruffdog]

No safety shut offs or such items?

The point being made is HOW a diesel is shut off. The only way to shut it off is cut off the air or the fuel. Most diesels use a solenoid to cut the fuel and the safety switches would be included in the items that control the solenoid. In the old days, a person had to pull a knob, lift the throttle pedal with your heel, or move a lever to cut the fuel at the injector pump.

 

[Diggin It]

UPDATE: Today I cut more very tall grass putting a moderate load on the motor. I started cutting and in exactly 55 minutes it died. The whole time I was cutting three things were being tested; First the fuel cap was unscrewed and was loose checking for a failure to vent. (This was done before but I'm starting to doubt my own results.) Also the test light was connected to the fuel solenoid and was brightly lit in my view testing any voltage failure to the now NEW solenoid. And listening to another contributor, I checked the transparent fuel filter housing making sure it was full before and after dying.
Upon dying the light never even flickered and stayed lit until the ignition was turned off. Also the fuel cap was still completely loose eliminating any fuel vacuum issues. And lastly, the filter housing was still completely full of fuel.
I waited 1 minute, restarted it and finished my cutting consuming exactly ten more minutes. It did not die again today. What am I missing here?

UPDATE> Ok, my test lights are complete and here are the results:
The white solenoid lead is the startup power. It does in fact come on with the starter and then go out. The red lead is the hold, and it also comes on when is running and stays on.
So, I finished cutting the grass this morning and was out of work for "overheat testing" so I started in and sat in my yard watching for the light bulb to go out when the engine died. Sure enough 30 minutes later it died and behold the light stayed lit until turning the ignition switch off. So my take is it's not the shut off solenoid but somewhere else, although if I had not just replaced it I would have suspected it to be bad.

If there IS fuel in the bowl on shutdown and the solenoid test light remains lit, that leads me back to airflow. How thoroughly have you checked for partially obstructed, collapsed or restricted air intake hoses?

With a gasoline engine, blocked exhaust lines can cause problem with back pressure. Can that be an issue with diesels?