JD 520

Having trouble with a JD 520. As long as I keep the starter pedal down, it runs, but when I let up on the starter, It stops. Sounds to me like an electrical problem, but I haven't found the problem yet. Any ideas? Oh yes! Lately when I hit the starter, nothing happens. I have to hit the starter many times, then it starts. I have taken the starter off thinking this might be the problem. Thank you.

I don't know that tractor as such but if it has a ignition by pass to give it hotter spark the ballast resister maybe bad or when you took the starter off you hook something up wrong. As for the starter not working you may have a bad starter switch or poor battery cable connections

Started having a bit of a problem with starting my 520 as, like you, having to hit the starter button several times to get it to engage. Finally got to were it wouldn't engage. To eliminate the possibility of a bad connection I even tried to jump start it with negative results. Loosened the starter button by unscrewing it a few turns to give a little more length to the rod and then it worked. My guess is the starter switch is getting bad, not making connection. Temporarily, it is fixed until I can do a more complete repair.

Put the starter back on. It's not the problem.

The problem is the starter button that the pedal pushes. They tend to get burned and coated with carbon over time, as well as worn and pitted.

(quoted from post at 12:20:29 12/19/22) Put the starter back on. It's not the problem.

The problem is the starter button that the pedal pushes. They tend to get burned and coated with carbon over time, as well as worn and pitted.

Click to expand...

How's he going to replace the starter switch if he puts the starter back on???

Sounds like you have 2 problems

As long as I keep the starter pedal down, it runs, but when I let up on the starter, It stops. My diagram of the 520 shows a dropping resistor between switch and coil. It is either open or has some bad connections. Resistor is bypassed when starter is engaged, this keeps it running until starter is released.

Others have covered the starter switch problem.

The old 59 Ford pickup I had did that once, replaced the ignition switch did not help. Remembered the resistor on the firewall, it was open.

Hal, what you describe can be the result of MORE THAN ONE PROBLEM, let me cover each.

1) FAULTY IGNITION BALLAST RESISTOR....In cases where the engine fires/runs ONLY SO LONG AS the starter switch is engaged BUT STOPS FIRING/RUNNING WHEN NOT......The series external BALLAST RESISTOR (between ign switch and coil) is bad or open or its wiring is bad or open, or one of its connections. Those ballast resistors do go bad and/or burn open.

2) FAULTY STARTER SWITCH.....In cases where it takes several tries before the starter motor finally cranks the engine over, the saddle mount start switch may be bad due to burned, pitted, corroded contacts, thats fairly common.....easy to replace

3) Faulty copper button/terminal contact on side of starter under saddle mount switch is burned, pitted corroded whereby even a good starter switch may not allow the engine to be cranked over by the starter motor..A burned pitted corroded copper start button on starter motor side needs to be replaced or a new start switch will also get burned.

4) The pedal and rod assembly that pushes the start switch button down may be out of adjustment whereby its not pushing the start switch button down far and hard enough.

I would start by removing and inspecting the start switch contacts and replace if they are burned or badly pitted......When its off inspect the copper button on starter to see if its badly burned or pitted or carboned over. Clean up and smooth it down nice n shiny and it may be okay if not damaged too bad...........Make sure to get a new correct start switch with the extra small side terminal and insure its wired up to the coil correctly......Inspect the Ballast Reisitor and its wiring, it has to be wired with good connectiuions and have around 1.2 to 2 or so ohms of resistacne, if its a bad/open circuit the engien will fire/run ONLY when start switch is depressed.

You likely need a new starter switch and/or the starter motor copper button (located under saddle mount start switch) needs attention,,,,,,Check starter pedal and rod linkage to be sure its depressing start switch fully,,,,,,,,,,,Check ballast resistor and its wiring for correct resistance,,,,,,,,,

NOTE I have seen a few start switches that arent mounted just right whereby the contacts arent meshing right with the copper button

INSURE GOOD BATTERY, BATTERY CABLES, CONNECTIONS AND GROUNDS ARE ALL GOOD

Hope this helps, Im sure I missed a few things if so maybe the other fine gents can add to this. Let me know how it turns out or of you have more questions

John T In the RV near Dade City Florida

If a 12 volt system on it. The ballast resistor is bad.