JD 4100 cutting out

[bryant1313]

My 4100 is cutting out. First I thought it was a fuel problem but I changed the filter etc. and have concluded it is electrical. Something is clicking right when it cuts out. It may be a bad seat switch?...how do I jump to see if that is the problem? What else can cause this to happen? Is there a relay or silenoid that is trying to shut off the engine when I hear that click?

 

[dbdartman]

The "click" is likely the fuel shut-off solenoid, on the back of the HP pump. Typically, when the tractor won't start, it's the "thermister" (thermal resister) behind the fuse box that's bad. It's a $4 part, the size of a little finger nail, & takes only a minute to change (after spending the prerequisite 2 hours getting to it).

Since your problem is intermittent, it can be much harder to diagnose. I would, however, recommend you first change out the thermister, as they are a common problem with the 4000 series, then see what happens, before going for the solenoid (over $50). Of course, keep an eye for loose wires/connections, especially at the ignition switch.

Thermister:

Shut-off solenoid:

 

[bryant1313]

The "click" is likely the fuel shut-off solenoid, on the back of the HP pump. Typically, when the tractor won't start, it's the "thermister" (thermal resister) behind the fuse box that's bad. It's a $4 part, the size of a little finger nail, & takes only a minute to change (after spending the prerequisite 2 hours getting to it).

Since your problem is intermittent, it can be much harder to diagnose. I would, however, recommend you first change out the thermister, as they are a common problem with the 4000 series, then see what happens, before going for the solenoid (over $50). Of course, keep an eye for loose wires/connections, especially at the ignition switch.

Thermister:

Shut-off solenoid:

I found the problem. Just as I suspected but failed to find the first time....it was the seat switch. I just bypassed it and ran it for well over an hour moving snow and it did not cut out once. There was a broken wire right where it goes into the switch....I think it was red/white....anyway it was broke with just one copper strand left and it was green from corrosion.

Now I am thinking I should carry a thermistor on hand...just in case? What does the thermistor actually do? And it it prevents starting the engine can you still jump it across the solenoid?....or is that not its sole purpose?

 

[dbdartman]

It takes more power to actuate (retract) the solenoid than it does to keep it retracted. The thermister reduces power to the solenoid so it will last longer. The solenoid has THREE wires. I wasn't sure which did what, so I didn't try jumping it out for fear of letting the magic smoke out.

Glad it turned out to be a simple fix!

 

[bryant1313]

what is the part # for the thermistor for a 2000 JD4100? Since it is only 4 bucks, I better have one on hand.

Thanks for all the help