[dexter91]

A few weeks ago I posted that my recently acquired 1987 850 suddenly wouldn't start after brush hogging for 15-20 minutes. After some maddening troubleshooting I took battery terminal connections off, baking soda/water cleaned them, took all fuses off, baking soda/water and toothbrush to all 6 and bam, tractor works fine. Until now.

I used it a few weeks maybe 4-5 times doing light work. No issues. Was brush hogging the other day for maybe 30 minutes, stopped for a break, pulled throttle back to let engine die, got up and left. I got back on it around an hour later, saw I left the key in the "on" position and it wouldn't crank. I assumed it was a dead battery so I tried a battery booster (Noco GB50). Nothing. I get lights on panel but no noise when I turn key to start. If I remember correctly when I started troubleshooting this, I would get nothing when I turned key to start and a "clunk" when I discontinued the start attempt but not in the last day or 2. Just silence when I turn to "start" and silence when I go back to "on"

I took battery to auto store, tested 100% and 98%. I bought some battery terminal cleaner, a brush and I took connections back on, sprayed them down, brushed them, added the battery terminal "grease" and reconnected. Nothing. Took fuses back of, cleaned again with the battery terminal cleaner, reinstalled. Nothing.

I tried jumping with my truck. No start but it appeared the instrument lights were brighter (or I'm imagining things...).

I've watched dozens of YouTube videos and read dozens of articles. It seems I first need to assume it's an electrical issue and work from that angle. Sounds good and I get the idea completely in concept but I have no idea how to go about that with my tractor. It seems every video/article showing this process looks nothing like my setup. So I'd like to eliminate safety switches (I think mine only has a neutral safety?) and the starter solenoid. But how? I've read/seen videos how people can "jump" the starter by connecting directly from battery + but I have no idea how to do this on mine.

Last thing I did was pulled off the hood (and messed up the threads on one of the screws...) and I took the battery ground from the frame, cleaned off all the mud/oil grime and reconnected it. Nothing.

Attached are photos of my tractor.

I'd appreciate any advice on how to troubleshoot this to isolate the problem.

Secondly, does anyone know a good JD mechanic in North Ft Worth who can come out if I can't get this going in a few days? My "to do" list is only getting longer around the house.

-Dexter

 

[theduke]

Where is the Small wire to starter?...I don't see it in the pic.

What is that added on circut breaker doing in the system??...Looks like a trouble areA..for sure.

Did you pull Red wire(big one) from starter stud and clean that area?

 

[dexter91]

Where is the Small wire to starter?...I don't see it in the pic.

What is that added on circut breaker doing in the system??...Looks like a trouble areA..for sure.

Did you pull Red wire(big one) from starter stud and clean that area?

Yes to pulling and cleaning the starter stud. I used the battery terminal cleaner from Autozone, battery brush and applied the battery "grease" stuff they sell to it.

The small wire to starter is on the underside. Two photos attached. One is side view and one is front view of the starter. I'm just learning that I can connect batt + directly to that little wire to starter and that will bypass the ignition switch, all safeties and the solenoid correct? What gauge wire should I use for this?

I have no idea about the added on circuit breaker. It's a used tractor and I'm extremely new to this. I don't have the background to see what's good/bad as far as add ons. Appears someone also bypassed a safety of some sort behind/under the seat also.

 

[JDJake]

The wire bypassed on the rear probably went to the PTO safety switch.

 

[Superglidesport]

Get yourself a digital DVOM / Digital Volt Ohm Meter and learn how to do a voltage drop test to "pinpoint" the problem.

Starter Circuit Voltage Drop Test

Voltage Drop Testinging Video

 

[rydplrs]

I use 2 screwdrivers to jump from big terminal to small. Touch the posts then cross the screwdrivers. I’ve also used welding rod and a coat hanger.

 

[dexter91]

Update 1: I went back out to tractor. I ran jumper cable and wire from batt + to spade on the bottom of starter. Started right up. So now I'm off to pin point location of electrical fault.

I may have also determined I have a bad ground. I had key out of ignition and my 4 year old had the light switch on. I accidentally put light switch to "hazards" instead of off. I put key to "on" and then began hooking up jumper cables. When I hooked up the black jumper cable to the batt - and then to the tractor frame the hazards started blinking and the instrument lights came on.

 

[theduke]

This is a typical issue with this vintage. Had one I never did figure out.

Keep a 12" piece of wire under the hood and your good. Most times you can just "bump" starter with jumper wire and the key will then start it.

It would appear that your entire dash /lights and wtfeverelse is Powered through that Circut breaker set up.
Judgeing from the rust and amount of Crimp on type connectors..........Thats the first part I'd address or return to its factory configuration.
Battery red wire feeds starter.
Everything else is fed from smaller wire off starter post.

How does your engine turn OFF....You mentioned with the throttle lever...?
Does the Key Not turn it OFF??

Just curious as to your shut down proceedure.

 

[charmalu]

I did a Google search for a 850 wiring diagram, but here is a 1050, almost the same.

https://www.tractorbynet.com/forums/attachments/screen-shot-2019-08-19-at-8-44-03-pm-png.617803/

Hope this helps.


Charlie

 

[dexter91]

This is a typical issue with this vintage. Had one I never did figure out.

Keep a 12" piece of wire under the hood and your good. Most times you can just "bump" starter with jumper wire and the key will then start it.

It would appear that your entire dash /lights and wtfeverelse is Powered through that Circut breaker set up.
Judgeing from the rust and amount of Crimp on type connectors..........Thats the first part I'd address or return to its factory configuration.
Battery red wire feeds starter.
Everything else is fed from smaller wire off starter post.

How does your engine turn OFF....You mentioned with the throttle lever...?
Does the Key Not turn it OFF??

Just curious as to your shut down proceedure.

Hey Dan,

Thanks for your advice. As for the shutdown procedures, the guy who sold it to us said the way to shut it down is to reduce throttle all the way, let engine die, then remove key and that's also verified by the OM for the tractor. I can't copy and paste the text but attached is a screenshot from the book. I suspect the key might also turn the engine off but I don't know if I've tried that way.

I also am not a fan of the current circuit breaker setup but I'm not yet knowledgable enough to change his jerry rig setup to factory condition so when I get to that part, I'll likely take to a real JD mechanic.

 

[JDJake]

This is a typical issue with this vintage. Had one I never did figure out.

Keep a 12" piece of wire under the hood and your good. Most times you can just "bump" starter with jumper wire and the key will then start it.

It would appear that your entire dash /lights and wtfeverelse is Powered through that Circut breaker set up.
Judgeing from the rust and amount of Crimp on type connectors..........Thats the first part I'd address or return to its factory configuration.
Battery red wire feeds starter.
Everything else is fed from smaller wire off starter post.

How does your engine turn OFF....You mentioned with the throttle lever...?
Does the Key Not turn it OFF??

Just curious as to your shut down proceedure.

They shut down the same way old CAT equipment does, Pulling the throttle all the way back kills the fuel supply from the pump.

 

[theduke]

Ok thats the way then.

Similar to the same vintage Kubotas.

So if you turn key off....Your engine will still run but your battery will likely not charge.

Does this Have Glow Plugs or a heater system....?

Again my curiosity strikes...I can't stop me sometimes.

I'm guessing They were blowing fuses or something that led to the path of installing CB.

 

[theduke]

Snagged this from your other post.
What is the Starter over ride Switch..????

Is it on the clutch pedal??
You have quite possibly one of the last of the Old School tractors of this size.

It Has NO BRAIN
You can start it with anything you can stretch cables too...or push/roll start. ( not fond of this but in a pinch)
Short of the lights ....you don't even Need a Battery.
It will run till out of fuel or you Quit

That is a Winner.......Stupid simple and not dumbed up with any goofy crap to render it useless.

 

[charmalu]

On the 1050 diagram I posted they call it the Neutral Start Switch,
and the 850 they call it the Starter Over Ride Switch. Both are wired
exactly the same.
I have the 950, wired the same. I have the wiring harness on the work bench
doing some repair work. I have one plug that has a wire looped between 2
of the holes. Going through my Diagram, looks like it goes the the Neutral
Start switch. Iam thinking some prior owner may have had a starting issue
and did the by pass on the plug.
This might be Dexters starting issue. Just a thought..

Charlie

 

[dexter91]

I did a Google search for a 850 wiring diagram, but here is a 1050, almost the same.

https://www.tractorbynet.com/forums/attachments/screen-shot-2019-08-19-at-8-44-03-pm-png.617803/

Hope this helps.


Charlie

That appears to be the wiring diagram for my 850 also, I have a late serial number.

 

[charmalu]

Do you have a set of manuals for your 850?
When I bought my 950 I did not even get the operators manual.
So I did some searching and found this guy on e-bay for a set
of reprints of the official manuals. Operators, service and parts
set.

Service Manual Set For John Deere 850 950 Tractor Parts Operators Catalog Shop 754472634545 | eBay

Find many great new & used options and get the best deals for Service Manual Set For John Deere 850 950 Tractor Parts Operators Catalog Shop at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Only problem is the wiring diagrams only go to 1980, if there were changes from then to
1989 at the end of production probably not too much.
At the bottom of ea page is the LITHO print date. I see from 1977 thru 1980 on the various
sections.
Been searching for newer manuals, a few official JD manuals do show up with a date of 86.
Here is where I found what is listed on E-Bay Under Heavy Equipment Manuals & Books
they type ed in John Deere 950 and all related to 850 - 1050 come up.

I asked this guy a question but no reply. This one goes to 86. (Does this have the wire diagrams?)

JOHN DEERE 850 900HC 950 1050 TRACTOR TECHNICAL SERVICE REPAIR MANUAL TM1192 | eBay

FOR SALE IS A SERVICE MANUAL THAT IS PICTURED.

www.ebay.com

Charlie

 

[AJgrn78]

Looks like it was mentioned but the ONLY starter override on these tractors is the neutral safety switch on the Low-N-Hi range shift lever.

 

[rydplrs]

Looks like it was mentioned but the ONLY starter override on these tractors is the neutral safety switch on the Low-N-Hi range shift lever.

My 750 had one on 1-2-3-4-5 shifter, not the H/L