Mowing Need help if possible

[calvincoolidge]

I just bought a JD 790 used. The guy I bought it from looks to have taken really good care of the tractor. I ran it for about 7-8 hours the first day cutting roads and plots. It ran like well oiled machine. The next morning I hopped on and started cutting. It would run for about 3-4 minutes and would cut off. It didn't spit and sputter like there was something wrong. It cut off like you would stand up off the seat, or a safety feature was kicking in. It would crank right up and cut another 3-4 minutes and do the same. After about the 5th time, I trailered her back up. Anyone ever have this problem before? Anyone have any suggestions? I can take it to the dealer, but if it is a simple fix I had rather not. I'm open to anything. Thanks in advance to any suggestions.

 

[plowindeeper]

maybe something in your fuel tank (sludge build up, acorn, leaf, ect) happened to me once or a lose safety wire that happened once also

 

[DennisFolsom]

My first thought is that it might be a either a clogged fuel filter or water in the fuel. Some of the more experienced guys on here, especially those who have owned JD 790's, may have other suggestions.

I suspect that, when you change the fuel filter on that model, you will have to bleed the air out of the fuel system to get it going again.

 

[foggy1111]

It's a fuel problem IMO. First thing you might do is change the fuel filter and get any contaminants out of the "bowl".

Next thing is check your points and condensor. (OK....that's a joke :laughing).

 

[whbrittain]

I just bought a JD 790 used. The guy I bought it from looks to have taken really good care of the tractor. I ran it for about 7-8 hours the first day cutting roads and plots. It ran like well oiled machine. The next morning I hopped on and started cutting. It would run for about 3-4 minutes and would cut off. It didn't spit and sputter like there was something wrong. It cut off like you would stand up off the seat, or a safety feature was kicking in. It would crank right up and cut another 3-4 minutes and do the same. After about the 5th time, I trailered her back up. Anyone ever have this problem before? Anyone have any suggestions? I can take it to the dealer, but if it is a simple fix I had rather not. I'm open to anything. Thanks in advance to any suggestions.

You didn't say if you refueled. It sounds like a clogged fuel filter to me. Water being the most likely culprit.

 

[tomd999]

Hiya,

The first troubleshooting step would be to loosen the fuel filler cap when it dies and if you hear air rushing into the tank, your tank vent is plugged or the vent in the cap is plugged.

Tom

 

[dex3361]

Sounds fuel related to me. I would do as the others have said check the tank vent. Inspect the inside of the tank for debris. Check the fuel flow from the tank while you have the fuel filter off. Replace the fuel filter and read up on bleeding the air out of the injectors before you start.:thumbsup:

 

[Egon]

Good Morning and Welcome.:thumbsup::thumbsup:


Another voice citing fuel delivery problem.

Check all the fuel supply hoses as well right up to the injection pump.

There will be other threads describing the same type of problem you have.

 

[Soundguy]

deffinately sounds like fuel...

soundguy

 

[kennyd]

I would jumper the seat switch to take that out of the loop. The didn't spit and sputter comment suggests to me it's not fuel related.

 

[Henri88]

Have to agree with Kenny. The OP says that it starts right up. If it was fuel starvation it would usually take a little longer before it would fire up.

 

[Soundguy]

you've never seen a diesel just shut down when the injectors went dry?

it's about the ONLY way I've seen em go.. just going along at full power.. then the thing coasts to a stop... especially if it will restart and run just a lil bit after setting.. that's sounding like fuel dribbling thru an obstruction.... not an open / closed switch.. etc.

gassers.. carbe'd gassers? now I've seen them sputter as they suck more fuel via choking action and the gove working the throttle butterfly as rpms are dropping with throttle still set high.. grabbing vapos or that last drip of gas from the carb bowl.. etc..

soundguy

 

[Henri88]

Yes, when you run out of fuel, but fuel starvation cause by a clog filter or obstruction in the tank or fuel line by my experience usually started with a lack of power a few second before dying. But the thing that make me question the fuel is he says that it starts right away after it quit on him. Every time I had fuel starvation on my diesel equipments, it would usually take a few minutes before we could get it started again, and most of the time they just wouldn't start. Once again, this is through my experience, some of you may have experience different situation.

 

[Soundguy]

fuel cutoff solenoid would be another possibility.. for instant off, but then run again with little down time.

soundguy

 

[Henri88]

Any news on your problem?

 

[calvincoolidge]

Here is an update. I decided to start with the least expensive solution and bought a new fuel filter. When I was changing the filter out I noticed there was a lot of debris. After changing the filter I cranked her up and cut for a couple hours with no problem. I hope this is the solution and not the bandaid. I appreciate everyones opinions. I am new to this site and really like it. I will have many more questions to come.

 

[The Dougster]

Had the same problem with my now 3-year old Kubota... exact same problem!
As it turned out, a rubber hose coming off the hydraulic pump had weathered and cracked allowing it to break suction... a visible inspection of hoses wouldn't hurt.

 

[Soundguy]

DEPENDING ON THE DEBRIS TYPE.. YOU MAY WANT TO CLEAN THE TANK.

WAS IT BIOLOGICAL.. OR DETERORIATING RUBBER? OR RUST?

sorry for caps.. am at work task swapping..

soundguy

 

[Henri88]

Good news! Have finger crossed. Soundguy also brought up a good advice. :thumbsup:

 

[RoyJackson]

I suspect that, when you change the fuel filter on that model, you will have to bleed the air out of the fuel system to get it going again.

The 790 has an auto-bleed system.