JD 3520 Dies for no reason.

[737800]

Own a JD 3520 bought new summer '05. 400 total hours. Operating machine normally for half day when tractor quits, just as if you hit a kill switch. Tractor will restart, run maybe 15 minutes, then die again. If I let tractor sit a day, it will sometimes run a whole day without problems then dies again.

Dealer could not duplicate issue, tractor out of warranty. Dealer checked fuel and fuel system, found no issues. He replaced a visually corroded relay, brought it home, 2 days later same issue.

Operating conditions:
Florida
Bush hog, front loader, dry conditions, some 15% grade (slew, dirt piles)

Already tried:
Drained fuel and fuel tank, replaced all filters
Bypassed kill switch in seat

Problem occurs:

All load conditions, different operations. Different fuel loads.

Any Ideas?

Thanx, Steve

 

[dixie306]

There's a plastic ring that fits on the top of the fuel filter, if its not on just right, it'll cause mine to act something like yours is

 

[737800]

Thanx,
I will check that when I get back. The tractor is definitely running as if it occasionally is getting air in the line from some where. I have heard that a pin hole in any fuel line on this particular engine will cause it to falter. A seal out of place any where in the fuel system might cause this also.


Steve

 

[kennyd]

Check/verify all the safety switches, not just the seat switch.

 

[tomd999]

Hiya,

Try this: Unscrew the fuel cap a turn and run it. If it runs fine, you have a plugged tank vent hole, clean or replace the cap. A plugged vent may cause the system to draw air in at any point it can, giving you the air in the line syndrome.

Tom

 

[Ken Cunningham]

After it cuts off and you try to start it back right away does the fuel selonoid click when the key is in the run position?

 

[737800]

Ken,

Not sure what I would be listening for, I have noted no unusual sounds or reactions when I restart it.

Acts fuel starved on some of the restarts, i.e. I have to crank it longer than normal to get it running again. I have always believed I am dealing with a transitory air in the fuel system problem, I just can't figure out what the source is. The pattern of the event is what really throws me off. I can sometimes run it 8 hours without recurrence, then suddenly the tractor quits every 5 mins or so.

I believe the relay the dealer replaced (which had contacts that visually appeared corroded) was the fuel shutoff solenoid (?) relay. Dealer could not duplicate the problem, but was checking the fuel system based on my description of the issue when he replaced the relay.

Lots of great ideas gentlemen, can稚 say thanks enough! Won稚 have a chance to trouble shoot this again till next weekend. I am going to check everything you all mentioned. Keep the ideas coming!

Steve

 

[Ken Cunningham]

Bear in mind i have only owned 1 tractor so the way mine works is all i know about them, I have a JD 1070. You should hear a click when you turn the key to the run position. That would be the first pos when you turn the key, not the start pos, at least thats what mine does, that click is the fuel solenoid. I am assuming yours would work the same way, someone chime in here if im wrong. If you can hear a click when it will start and when it wont, then at least you know its not the fuel shutoff.

 

[737800]

Thanks Ken,

You are absolutely correct. Just checked. I had not associated that click w/ the fuel solenoid but have always heard it. No change. (I thought that was associated with the ignition system, learn sum in new every day).

Anyway, still trouble shooting.

Steve

 

[Ken Cunningham]

Have you checked the tank cap like tom mentioned? Right after it cuts off you could unsrew the cap and if you hear a swoosh of air into tank, thats bad.

Fuel line shouldnt cost much. I dont know how much trouble it would be to replace the fuel lines on your tractor, but if its not hard to do then that would be a cheap and easy way to rule that out. Heck you might even run acroos a loose clamp while your doing that and fix the problem. Let us know how it turns out.