JD Starting Problem

[Anonymous-0]

Finishing up my fix-up/paint-up project JD 2020. When I try to start it now, it will run as long as the key is in the Start position. When I release it to the On position, it quits.

I checked for power at the coil by disconnecting the positive wire and testing with my volt-ohmmeter to a chassis ground. Again, I get no power in the On position but current in the Start position.

I did not rewire the ignition switch but I did replace wiring to and from the neutral safety switch (under the plate on top of the transmission hump). The tractor is in neutral.

What am I missing here? I don't have a wiring schematic and I don't see one on the JD web site. Thanks, guys.

 

[buickanddeere]

Ballast resistor or the ballast resistor wiring is open/broken.
The coil should be a 6V with approx 1.5 ohms and the ballast should be approx 1.5 ohms.

 

[John T]

New generation isnt my thing and I agree with the good Buick man it may be some sort of ballast resistor problem HOWEVER I dont know if that model has the ballast right there on the switch or uses a resistive wire link (looks like a wire fuse link) or what???????? Basically those systems with the ballast and the start by pass apply unballasted battery voltage to the coil (by passing the ballast) ONLY while in the start/cranking mode but then voltage n current is limited to the coil since the ballast is then in line series after the switches IGN output but before the coil. If such a resistor and by pass system is what you have?? the coil hAs voltage while cranking but since the ballast is bad/open thers no voltage otherwise......

No warranty on this cuz I dotn know new gen tractors

John T

 

[rrlund]

Let me think on this for just a while. My 1020 has done it before. Can't remember right off the top of my head what i did to fix it. I know I put a new switch on it once,maybe that was why.Seems like there was more to it than that though.

 

[JDemaris]

The original setup can be easily improved. OEM Deere used a special ignition switch with built-in resistor bypass and a resistor wire. On the OEM switch - terminal #4 goes to the resistor wire on to the coil.

Save yourself some trouble. Make sure you've got the OEM type non-built-in resistor coil. Mount a good ballast resistor near the coil - you can buy one any good auto parts store for less than $10.
Then - hook the IGN of the key-switch to one side of the resistor, the other side of the resistor to the + side of the coil. Then, run a wire from the "R" terminal on the starter solenoid to the + side of the coil - and you're all set.

If you don't use an equivalent to the OEM 6 volt coil - you're apt to have cold-weather starting problems.

 

[Anonymous-0]

Thanks fellas. The system is 12V. I also suspected the ballast resistor so last night while I was in town I got a new coil with built in resistor (the existing coil looks like its thinking about dying anyway).

Thought I might also replace the ignition switch and run new primary wire to the coil, again all those look like original 30 yr old items.

I didn't know about them sending unballasted current to the coil during cranking. That would make perfect sense that it would be the resistor.

Thanks again, you guys are great.

 

[Walt Davies]

I don't see how this will solve your problem. Do you have two wires going to the + side of the coil if yes then one goes to the starter solenoid the other to the ignition switch. You need to trace the power from the switch to the coil to see where it stops then fix that part. Adding more parts will just make it more confusing and most likely won't fix the problem.
If your wire from the switch to the coil has a built in resistance then adding another coil with a built in resister will only cause more trouble and lower spark output.
Also it will nullify the advantage of the 12 volt start from the solenoid.
Making changes to an already working system can only upset what the designer had created for this system. I alway put things back as they were so as not to create more problems down the road.
Walt