1971 4020 Diesel starting issue

Scott 730 · Aug 28, 2017

Idiot lights on dash seem to work fine. But the starter does not turn over with the key. Jumped the starter solenoid with the key on and it turns over great but no start. Thinking now that maybe the shutoff on the injector pump maybe also has no power. I found 2 used relays under the seat, so the previous owner must have had some issues also. Manuals are on the way. Where can I start checking first for problems? Starter switch, circuit breakers,,,,,? Thank you.

cornerpost · Aug 28, 2017

Check the relay under side panel above and
behind starter. Had a 4000D with same
symptoms. After 40+ years nut on terminal
of relay decided to loosen and poor
connection happened.

Bob · Aug 29, 2017

I haven't been around the later 4020's lately, don't remember for sure if they have a wiring harness connector under the back of the hood, like the older ones, if so, poor/dirty/overheated/bent connections there are common, also the harness connector low down in the rear of the control pedestal.

Check for power to the fuel shutoff, get that working, no crank could be neutral safety switch or associated harness issues.

Tx Jim · Aug 29, 2017

I'l suggest to check neutral start switch on RH side of trans. Sometimes if NS switch isn't making contact one can remove a sealing washer or two & get switch to make contact. Next check to be sure relay on LH side of firewall above starter is getting a good ground & is operating when ign switch is turned to start position.[/url]

Scott 730 · Aug 29, 2017

Thank you all for the advice. I won't be able to work on it until next week. Do I need to see a dealer to get a wiring diagram? It is not in the online parts book like it is for my 730D. Thanks again.

1971 4020 Diesel starting issue

Scott 730

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cornerpost

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Bob

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Tx Jim

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Scott 730

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