JD X749 Dying after 30-45 minutes

[Mike VS]

FAILURE! I bought the new solenoid with total optimism and installed it this morning. All started well, but sure enough 40 minutes later it died. I let it sit 2 minutes and got 5 more of cutting time. After a 10 minute sit I finished the job of 15 minutes cutting.
The temp gauge was at 33% of the green and was again not acting hot. The good news was that I only paid $14 delivered for this so I'm not too pissed. So what's everybody's next idea?

 

[wvgca]

okay, so you're out 14 bucks, not big deal ...
anyways, what else feeds it?? just one sensor or two??

 

[Mike VS]

okay, so you're out 14 bucks, not big deal ...
anyways, what else feeds it?? just one sensor or two??

There are two hot wires going to the solenoid, one gets hot upon startup, the other gets hot when ignition is on while the start up goes cold. I have been advised here to rig light bulbs to those and see if I lose the hold power. I've been too busy to do it hoping this would just solve the problem. I'll rig the bulbs soon but if I do lose power to the hold solenoid, where would that sensor be coming from?

 

[wvgca]

probably from the temp gauge, not sure, you would have to find a wiring diagram ...
you can put in a new temp gauge [especially if it's cheap] or take it right out and put a plug in the hole ...
this will [kinda] simulate a cold engine to the solenoid, maybe it might make a difference ..

 

[Mike VS]

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.

The past poster suggested I remove the temp sender which is a little overkill, maybe I'll remove the sender wire and see if it dies. What possible other sensor could be doing this?

 

[wvgca]

if it's got murphy type switches, they will be on the water temp, and the oil pressure anyways, but the light would have gone out ???
your back to a vacumn forming someplace, try running with the gas cap loose, or change the fuel filter, or both .

 

[Mike VS]

if it's got murphy type switches, they will be on the water temp, and the oil pressure anyways, but the light would have gone out ???
your back to a vacumn forming someplace, try running with the gas cap loose, or change the fuel filter, or both .

Yes, I switched it with my other JD tractor, THEN loosened it while cutting... still died. And I replaced the fuel filter.

 

[radios1]

Yes, I switched it with my other JD tractor, THEN loosened it while cutting... still died. And I replaced the fuel filter.

it's not senders or sensors. the only thing that will stop a diesel is cutting off the air or fuel supply, does it have a lift pump?. that could be bad, if not, then you may have junk in your tank, or fuel lines, don't waste time with senders or sensors, it's the fuel supply!!..

 

[crashz]

Well, you are making progress. You know that the tractor is not shutting itself down due to a sensor or failed hold coil.

The timing thing is weird, but once shut down you have limited use until cooled. Or maybe fuel is restricted?

I know you tried swapping fuel caps, but maybe its not vented through the cap. Maybe the tank vents another way? I would try two things:
- Try running it stationary without any fuel cap. Open top. Or mow for 25 minutes with the cap on, park it idling, and unscrew the cap and leave it off. If it still runs or if you feel a vacuum, you know you have a vent issue.
- Its possible that the tank could have something in it that is blocking the fuel feed hose. If/when it dies again, leave it dead, grab a drain pan and pull a fuel line off of the filter housing.

I doubt this is a pump failure as once they die, they don't typically restart at all.

 

[Mike VS]

Well, you are making progress. You know that the tractor is not shutting itself down due to a sensor or failed hold coil.

The timing thing is weird, but once shut down you have limited use until cooled. Or maybe fuel is restricted?

I know you tried swapping fuel caps, but maybe its not vented through the cap. Maybe the tank vents another way? I would try two things:
- Try running it stationary without any fuel cap. Open top. Or mow for 25 minutes with the cap on, park it idling, and unscrew the cap and leave it off. If it still runs or if you feel a vacuum, you know you have a vent issue.
- Its possible that the tank could have something in it that is blocking the fuel feed hose. If/when it dies again, leave it dead, grab a drain pan and pull a fuel line off of the filter housing.

I doubt this is a pump failure as once they die, they don't typically restart at all.

Thanks... As far as the venting on the cap, I know that is not it. I literally had the cap falling off and it died. With that loose there would be no vacuum. Now a fuel blockage is possible, but due to how well it runs under a full load I just don't see it. There is 100% power under all conditions until it just shuts down. And it doesn't sputter and slow down, it dies like you shut the key off. Hard to believe the fuel supply is coming and going like that.