350 ignition problem

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scremineagle
430 crawler
430 crawler
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Joined: Tue Dec 20, 2011 1:58 pm

350 ignition problem

Post by scremineagle » Wed Dec 05, 2018 4:59 pm

Used this site many times when I first purchased my 350. Now been 2 problem free years in the woods until today. Crawler starts fine but when I let off the key engine dies. Ordered new switch but wasn't the problem. Anybody got any ideas. Thanks

scremineagle
430 crawler
430 crawler
Posts: 52
Joined: Tue Dec 20, 2011 1:58 pm

Re: 350 ignition problem

Post by scremineagle » Wed Dec 05, 2018 5:14 pm

Forgot to mention that it is a gas 1966

Jim B
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Re: 350 ignition problem

Post by Jim B » Wed Dec 05, 2018 6:59 pm

I wonder if your machine is wired such that there is a starting circuit having a wire from the solenoid to the coil. If it does it would start on that circuit and die when you let go of the key if there is a break of some type in the wire from the switch to the coil. I would first check to see if there is power at the coil when the key is turned to the on position. If no power with the key on, chase the wire back to where you find power. You can also try a jumper wire from a power source to the ignition wire side of the coil and see if it runs. Be careful about leaving the key, or the jumper wire, on for long so as not to burn your points. Unhook the wire from the coil to distributor or stick some paper (a folded up dollar bill) between the point contacts to insulate them, if you need the key on for long troubleshooting without it running.

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Stan Disbrow
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Re: 350 ignition problem

Post by Stan Disbrow » Thu Dec 06, 2018 5:26 am

Hi,

There is a resistor, or resistor wire, from the switch to the coil. That drops the 12v to 6v. This is where the issue will be.

When cranking, there is another wire, minus a resistor, to the coil. A bypass because the starter load drops the system voltage. This ensures enough spark while starting.

Running 12v to the coil will cook it over time. Pit up the points as well.

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

Jim B
440 crawler
440 crawler
Posts: 182
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: 350 ignition problem

Post by Jim B » Thu Dec 06, 2018 6:37 am

Hi Stan,

Thanks for confirming there is a resistor wire in the harness, that should narrow his search. With your info I studied the parts catalog a bit and found the reference to the resistor wire. It looks like the wire is NLA and they use a ballast resistor too replace it.

Jim

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Lavoy
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Re: 350 ignition problem

Post by Lavoy » Thu Dec 06, 2018 8:36 am

350 does not have a resistor to my knowledge, it is Delco style starter, resistance is in the solenoid itself. I would check for broken wire as stated earlier or replace the solenoid.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

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Stan Disbrow
350 crawler
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Location: Raleigh, NC

Re: 350 ignition problem

Post by Stan Disbrow » Thu Dec 06, 2018 2:17 pm

Hi,

Yes, the resistance is likely inside the starter solenoid itself. Sometimes Delco stuff used a high resistance wire. But, that resistance is there for the Run circuit somewhere. I would check with an ohmmeter, the wires first then the solenoid Run path.

There is not likely to be an obviously stand-alone resistor. I say it that way because someone may have 'fixed' this in the past by using one. I clearly recall seeing machines where a spliced-in resistor was dangling out from under hoods with duct tape on the connections.... :P

Sometimes stuff gets robbed out of cars and trucks, too. All sorts of oddballs not in a Deere manual. I, myself, have a bypass set of wires and a toggle switch on my 420 because the Ignition position on the original rotary switch is intermittent. The rest works (lights) and I did not want to disturb the original wiring 'rats nest' behind the dash to replace the switch for one section being Out. ;)

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

Jim B
440 crawler
440 crawler
Posts: 182
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: 350 ignition problem

Post by Jim B » Thu Dec 06, 2018 7:09 pm

I did a little more checking up on my memory. The parts catalog does call out a resistor wire in the harness. It subs a couple times and ends up as AA5791R two terminal resistor. I would say scremineagle will need to run a new wire from the switch to a terminal on new ballast resistor, then another from the other terminal of the resistor to the coil + terminal. The starter solenoid has a terminal marked "R". The wire from it should go to the + terminal of the coil now, along with the existing resistor wire from the ignition switch. The wire from the solenoid should remain in place as when the starter is energized; the same contact plate in the solenoid that connects the big contacts to power the starter motor energizes that terminal as well; supplying full battery voltage to the coil + terminal to aid starting. It deenergizes when the solenoid deenergizes. This would explain scremineagle saying his crawler would run when he had the key in start and dying when he let off the key (returned to the run position).

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