4020 won't start

gwillhoite · Mar 11, 2018

Bought a 1970 JD4020 diesel about a month ago and have started it once every week just to see if there were going to be problems. I have no alt light when I turn key on. With key on, solenoid, alt and power terminal on key switch has 12 volts. With key switch to on, less than a volt to the alt and key switch. Same thing on the relay by the solenoid.
Could this be the starter?
Thanks, Gary

Bob · Mar 11, 2018

If battery's charged and power is getting to the starter solenoid, you could very well have poor connections at the connector in the main wiring harness that's located under the rear of the hood/front of the control pedestal.

There's another connector in the harness near the key switch, as well.

Either are COMMON sources of problems like this.

tim s · Mar 11, 2018

Check the connections under the cowl on the left side,,when I have one with issues like this I remove each circuit breaker nut, polish the wire end and install with a new nut with a star washer made on to it,,a good first step, and it usually fixes it..

dieselade · Mar 12, 2018

the only time my 4000 jd diesel,,same as 4020,, would not start was a tiny wire behind injector pump. a hard to get to connection had corrosion that needed cleaning.

gwillhoite · Mar 12, 2018

Thanks for the help all. I will try these suggestions in the next day or two.

4020 won't start

gwillhoite

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Bob

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tim s

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dieselade

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gwillhoite

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