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  1. #1

    Default JD 750 Compact Tractor - Starting Problems

    My 1983 JD 750 Compact Tractor with 602 hours on it has a random starting problem. Usually it starts right up, but some times nothing happens when I turn the key. When this happens the indicator lights come on but nothing else happens, it doesn't turn over or make any noises. It acts like the battery is dead but my multimeter shows the battery to be ~13.6 volts. Some times if I turn the key off and on several times it will start, but not always. Some times when it acts up like this I hook up some jumper cables and it will crank right up, but not always. I discovered this weekend that if I short across the two terminals on the starter it cranks right up even if nothing else is working. It appears that there are only two possibilities; either the ignition switch or the voltage regulator. But I don't have a wiring diagram so I don't know if I am missing something. Once it starts, it runs great.

    Can anyone tell me where the problem is or how to find it? I don't want to start replacing parts until I find the problem!

    Thanks!
    Dave...

  2. #2
    Veteran Member kebo's Avatar
    Join Date
    May 2006
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    2,311
    Location
    Lexington, SC
    Tractor
    2001 John Deere 790 4x4, bar tires

    Default Re: JD 750 Compact Tractor - Starting Problems

    When it misbehaves, do you hear the solenoid in the starter motor click?? If so, then it sounds very similar to the problem I had with the '84 750 that I used to have. I wound up having to add an extra relay to increase the voltage getting to the solenoid in the starter. After that, it worked perfectly everytime. It took me a LONG time to get that figured out. It 's a very long story as to why it does that, but I think John Deere actually offers the relay as a kit to improve the starting on older model tractors. Basically as a tractor ages (and most any other machine as well), most of the electrical connections develop corrosion/contamination or else just physically start to loosen up. Each connection point develops resistance which will drop the voltage (and limit the current) getting to the starter solenoid and starter motor. The relay jumps the battery straight to the starter only when the key switch is turned to the start position. Diesels have high compression and the starter needs every bit of voltage it can get from the battery, even moreso in cold weather.

    Before you go down that route though, I would check EVERY single connection starting with the battery, going to the ignition switch, down to the starter, and the grounds as well. Also, check the wires for any fraying. Clean all suspect connections, make sure all of them are tight.

    It sounds like your battery is ok, but just to be sure if you have another known good battery, you can try it in the 750 to see of the problem goes away or if it still does it.

    If you eliminate all the wiring and connections, and the battery, then that doesn't leave much but the soleniod/starter itself.

    Oh yeah, there are seveal threads on this so you might trying searching and get some more tips. Good luck, let us know if you figure it out.
    Nothing could be finer than riding my JD790 in South Carolina!!

    2001 John Deere 790 4x4 with Model 70 FEL, 5ft International World Agritech bush hog, 5ft Wallberg BB, 5ft Frontier disc harrow, 5ft King Kutter II Rototiller, 5ft Cultipacker, 5ft Sitrex finish mower, Leinbach PHD with 9" & 12" augers, Leinbach middlebuster, Leinbach #11 Field Cultivator, boom pole, custom 3pt handi-hitch, clamp on bucket forks, Pat's Easy Change.

    Nothing runs like a Deere, or smells like a John....

  3. #3

    Default Re: JD 750 Compact Tractor - Starting Problems

    There are no sounds at all when key is turned. No clicking, buzzing, humming, nothing at all. So I don't think that the problem is low voltage at the starter, but I will check it and if it is low I will look at all of the connections and try to clean them or at least disconnect and reconnect them. I have already searched for disconnected, loose and frayed wires, but I didn't find any.

    I also read on another site that, at least on an 850, the safety switches are another possibility. So if there is a problem with one of them it would prevent the tractor from starting. I believe that they are all two wire, so I should be able to check them by just jumping across their terminals one at a time.

    BTW - The starter was rebuilt last year because of this problem, even though the shop said that it was OK. This has not solved the random starting problems!

    Does anyone have any other thoughts?
    Last edited by DDeemer; 09-15-2009 at 01:07 AM. Reason: Correction

  4. #4
    Platinum Member
    Join Date
    Dec 2001
    Posts
    988
    Location
    Maryland

    Default Re: JD 750 Compact Tractor - Starting Problems

    Try checking the voltage at the small terminal on the starter when it is in a non-starting mode. If you are getting 0 volts, then the neutral safety switch or pto neutral switch is probably bad. If you are getting voltage, but it is lower than 10.5 volts, then the relay kit will fix it.

  5. #5
    New Member Mountaineer Deere's Avatar
    Join Date
    Sep 2011
    Posts
    4
    Location
    West Virginia
    Tractor
    1983 John Deere 750

    Default Re: JD 750 Compact Tractor - Starting Problems

    Don't know if this applys but I have to hold up on my PTO lever sometimes for mine to start.

  6. #6

    Default Re: JD 750 Compact Tractor - Starting Problems

    I had a 650 with the same problem. Not sure if it is exactly as yours but might want to try these: tap starting solenoid on starter with rubber mallet while you hold the key to the start position. If it starts check your starter. another is try and move your gear shift lever around slowly as there is a safety switch inside the gear case and the components that operate it can become worn, you can jump this switch out to check but remember the tractor will start in gear. If it turns out to be the starter good luck on getting parts as deere will only sell a complete starter. If you are lucky to know someone that can replacement starter parts that will save you a lot of money. If it is the switch in gear box not sure how to fix other than replacing cover and other parts that makes and brakes the switch.

  7. #7

    Default Re: JD 750 Compact Tractor - Starting Problems

    The relay problem is common, and I had to do that on my 950. However, if your solenoid isn't clicking it is doubtful that that is the problem. Next time it happens jiggle your range lever and see if that helps. If that doesn't, jiggle the pto lever and see if that helps. If either helps, check the wiring for those switches to make sure it looks good and if that doesn't work, replace the switch.

    Your starter sounds like it is fine. If it is clicking I'd say add the relay, but if it isn't, it's got to be one of those switches. The electrical on these tractors is pretty basic.

  8. #8
    Veteran Member Gizmo2's Avatar
    Join Date
    Jul 2006
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    1,918
    Location
    New York
    Tractor
    JD 2320

    Default Re: JD 750 Compact Tractor - Starting Problems

    I can't add any further comments to what has already been posted but I will say I have a brand new ignition switch for a 1988 JD650 just sittin in a box on a shelf (maybe it will fit). Don't ask why I have it!
    That would be #20 (Both the 650 and the 750 had the same parts catalog).
    -rwp4534________un01jan94-gif
    JD 2320, 200CX FEL/61" bucket , 46 BH/16" bucket, FEL Forks, 72" Snow Blade, Landscape Rake, Ballast Box, PHD, The Wife

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