JD 520 Won't stay running

Anonymous-0 · Jul 3, 2012

My tractor starts up quickly - but then dies as soon as I lift my foot off of the starter pedal. I checked the resistor - and found that it has been by-passed! I've owned and been using the tractor for many years - apparently with the resistor by-passed; does that mean the ignition system was upgraded or modified somehow?
What is the next thing I should consider?
Thanks a lot.
Tim

BushogPapa · Jul 3, 2012

Probably NOT...!!!

By-passing the resistor is actually only a temporary fix...
Full Battery Voltage continuously on the Coil and Points will just Burn up Points faster and over-heat the Coil...
I doubt the resistor is actually by-passed and what you see is the wiring for the By-Pass that is activated when you engage the Starter..!!
Once you stop the starter motor, the By-Pass circuit drops out and (if the resistor is bad) Ignition Stops..!!
Use a timing light and see when the ignition works and when it quits..

Ron..

El Toro · Jul 3, 2012

Sure sounds like you're only getting voltage to your ignition when cranking. That usually happens when the ballast resistor fails. Pull off a plug wire using a helper when it won't start and see if there's any fire to your plug.
I think Napa has ignition coils with builtin resistor's. Hal

John T · Jul 3, 2012

If it ONLY runs when the starter pedal is depressed, its NOT getting coil voltage via the ignition switches IGN output via any resistor (even if shorted around) then to the coil. If you turn the ign switch ON,,,,,,THERE MUST BE VOLTAGE TO THE COIL (starter engaged or not) and if not,,,,,,,,again theres no voltage at the switches IGN output or a break/open in the circuit from there to the coil via the ballast or its shunt by pass. A simple test lamp will show where voltage is or is not when the switch is ON and again if theres none at the coil when ON she can only run when the starter is engaged.

If the ballast were by passed and its still a 6 volt stock coil (i.e. wasnt changed to a 12 volt coil) the coil will overheat and the points burn up quickly. If it was changed to a 12 volt coil and the resistor was shorted around it will start n run and the coil wont overheat butttttttttt it should still have coil voltage with switch ON

John T

Wiring Diagram

Anonymous-0 · Jul 4, 2012

Thanks, Thanks, Thanks.
I was not getting voltage to the coil - so I traced the wire back to the battery (where it attaches on the post with the heavy duty cable) - when I touched it - it just fell off. I spliced, cleaned, reattached - presto!! running great.
Thanks again,
Tim

JD 520 Won't stay running

Anonymous-0

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BushogPapa

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El Toro

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John T

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Anonymous-0

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