620 starter problem

JD 620 won't turn over. the battery is good and so is the ground on the battery. I need a starting point on troubleshooting. if I pull the starter off is there a way I can test it?

check the ground where it connects to the tractor

If battery, cables and connections are good, my first suspect would be the mechanically-actuated switch on the starter.

That?s kinda what I think too. Do you have to replace the whole starter or can you just replace the switch

Switch is easily replaceable, trouble is there's a copper stud with a flat "wedge" on it protruding from the starter "belly" that serves as one of the switch contacts and you MAY find it badly eroded away.

Stud can be replaced, but that requires starter disassembly, a large "soldering copper" and some skill in soldering.

You'll have to have a look!

There's been many complaints about the poor quality of replacement switches sold today, I don't know what the best kind to buy would be.

Sometimes, NOS genuine Delco units come up on ebay, MUCH better than the typical stuff today.

Switch AR21115 is still available from DEERE for just under $40, I can't comment on whether it's any better than the ones the aftermarket places sell.

I see this very site has their version for $3.45!

The copper stud, 1932886, is about $33 at DEERE. It's a Delco number, you could try to find a Delco 1932886 on the 'net, if it turns out you need one.

If you pull the starter off remove the top button switch. Its held on by 2 screws. Look at the copper stud underneith. If it concaved and not flat on top it needs replaced. To test the starter put it TIGHTLY in a bench vise with switch removed. Hook jumper cables to a battery red to positive black to negative terminals. Clamp the other end of the cables black clamp to the starters nose cone out of the way of the drive. Put a large chisel or screw driver in the red clamp, metal to metal, and touch it to the existing copper stud. If it spins strong your problem is with in the starter switch, copper stud connection.

"[b:654c4848f0][i:654c4848f0]I need a starting point on troubleshooting.[/i:654c4848f0][/b:654c4848f0]"

Check the end of the ground cable where it is bolted to the frame.

Make sure it is making good connection with "clean" metal.

Using a test light, check the end of the cable connected to the starter switch on the starting motor for a good connection.


If the light shines, then the ground cable and power cable are making good connections.

[b:654c4848f0][i:654c4848f0]<font color="#ff0000">CAUTION: Please be mindful of common safety steps; expressed or not.[/i:654c4848f0][/b:654c4848f0]</font>

Before you begin this troubleshooting method, make sure of the following:

[b:654c4848f0][i:654c4848f0]Lock both brakes.

Shift the transmission into NEUTRAL.

Turn the ignition switch to the OFF position.

Remove the coil wire from both the coil and distributor.

Turn the gas off at the fuel filter.[/i:654c4848f0][/b:654c4848f0]

If there is power at the starter switch, then push the button to engage the starting motor.

If the starting motor engages, then check and/or adjust the starting motor pedal and linkage.

After checking and/or adjusting the starting motor pedal and linkage, then push the starter pedal.

If the starting motor does NOT engage, then remove the starter switch and check for wear on the copper contact.


If the copper contact is severely worn on the edge, then it may not be making a good connection with the stud terminal on the starting motor.

Inspect the stud terminal on the starting motor.


If the stud terminal is severely worn, then it may not be making a good connection with the starter switch on the starting motor.

You might consider replacing one or both if they are severely worn.

"[b:654c4848f0][i:654c4848f0]if I pull the starter off is there a way I can test it?[/i:654c4848f0][/b:654c4848f0]"

Remove the starting motor and connect the black jumper wire from the NEGATIVE battery terminal to ground the starting motor.

Connect the red jumper wire from the POSITIVE battery terminal <big>briefly</big> to the stud terminal on the starting motor.

If the starting motor engages, then replace either or both the starter switch and stud terminal.

If the starting motor does not engage, then make necessary repairs to the starting motor or replace the starting motor.

Hope this helps.

You ask "if I pull the starter off is there a way I can test it?"

If you have it secure in a vice with ground to the case and apply hot battery voltage to the starter it should spin fast and smooth not growl or stall or draw excess current HOWEVER while that non load test can show if its totally BAD (doesn't spin at all or slow etc) it doesn't indicate how it may still fail badly under a load and that's what really matters.

THAT BEING SAID before I suspect the starter motor itself IFFFFFFF battery and cables and connections and grounds are alllllll good, I FIRST SUSPECT A BAD STARTER SWITCH OR BAD POST ON THE MOTOR. The switches contactor can be burned or pitted or carboned OR the contact post on the starter can be burned or pitted or carboned !!!!!!!!!!!!!!!! If the starter switch is removed that can easily be determined. REMOVE THE STARTER SWITCH AND INSPECT IT If there are no bad burns or pits or carbon on the contactor or the starter post a good clean and light file smooth may help but if badly burned or pitted the switch OR the starter post may need replaced

I have also seen a problem when the starter switches push down button isn't getting pushed down far and hard enough to properly engage the switch contactor due to linkage or mechanical problems INSURE THE SWITCH PUSH BUTTON IS GETTING FULL ENGAGED DOWN HARD AND FAR ENOUGH !!!!!!!!!!

Ifffffffff the battery and cables and grounds and connections are alllllllllllll good if when you engage the switch battery voltage doesn't drop much (or a test light on battery doesn't dim much) I LEAN TOWARDS THE STARTER SWITCH OR POST ON STARTER MOTOR IS THE FAULT

HOWEVER if battery voltage drops drastically (test lamp goes very dim) I LEAN TOWARDS A FAULTY OR MECHANICALLY STUCK/JAMMED STARTER. Its possible the starter drive gear is stuck/jammed into the flywheel and if that's the case and all else is well the voltage will drop drastically INSURE STARTER ISNT MECHANICALLY STUCK/JAMMED.

Regardless check all cables and grounds and connections and insure a good full charged battery,,,,,,,,,,inspect the starter switch,,,,,,,,,INSURE THE SWITCHES PUSH DOWN BUTTON IS DEEP AND FULL ENGAGING,,,, if all else is good and it draws high current when engaged the starter motor itself may be bad but its often the other things mentioned above including the post on the starter (under the switch) is burned or pitted or carboned and that's much cheaper to fix then a starter REMOVE THE SWITCH AND LOOK SEE

John T

Should also make sure carb is getting fuel and diaphragms aren?t bad. Problem might not be in fuel but always check all of your bases.
Hope this helps,

WFF

(quoted from post at 15:24:55 02/02/19) JD 620 won't turn over. the battery is good and so is the ground on the battery. I need a starting point on troubleshooting. if I pull the starter off is there a way I can test it?

Click to expand...

I had the same thing happen on my 50, the starter button was not getting pushed down enough to engage the starter, thought I had other problems but finally figured it out. A couple of pennys, I am cheap and some kB weld did the treat, good luck with it.