Page 1 of 3 123 LastLast
Results 1 to 10 of 30
  1. #1
    New Member
    Join Date
    Jun 2009
    Posts
    4

    Default Reversed battery polarity on 8N

    I had a brain freeze and hooked up the 12v battery on our '52 8N on reversed posts. Seconds later, wires were smoking and I pulled the connections. The starter motor turns but I checked a plug and there's no spark and there are no lights. This tractor was converted to 12v last year. Have I got only fuse damage or bigger news like the alternator?

  2. #2
    Silver Member Lil_FarmerJim's Avatar
    Join Date
    Jul 2008
    Posts
    127
    Location
    South Eastern PA
    Tractor
    Kubota L3400HST

    Default Re: Reversed battery polarity on 8N

    Hey Frontman,
    I don't know about the 8N specifically but in general when you reverse polarity in a DC system you will cook anything that is dependent on a negative (or positive) ground , such as start motors, coils, etc. since they are dependent on the flow of electrons from only one direction. (Starter motors because power flowing the wrong way will run it in reverse) And the alternator, could be effected as its a similar to a electric motor and power flowing in the wrong direction might cause it to cook the internal wire windings as it fights to turn

    As for the fuses, they blow when the power traveling over the filament is more than its rated for.

    So if the motor cranks but you get no spark, I would check the ignition coil and see if it looks cooked. If its an electronic ignition, then I would bet that it's done for. The alternator would be the place I would look if the battery failed to charge or ran down after running it for a while.

    HTH
    Jim


    ------------------------------------------------------

    Life is too short to think about all the things you want to do, just go do them!

    Kubota L3400-HST with - LA463-1 FEL, Woods BH80x, Landpride 72 Landscape rake, Farm Force Middle buster, FF Tow rig, CA 42" pallet forks, CA 60" xtreme duty tooth bucket, KW manufacturing 84" dozer blade, with hydraulics.

  3. #3
    New Member
    Join Date
    Jun 2009
    Posts
    4

    Default Re: Reversed battery polarity on 8N

    Thanks Jim. I'll check the ignition coil to start with. By the sounds of it, my starter motor is running backwards at this point.

  4. #4
    Silver Member Lil_FarmerJim's Avatar
    Join Date
    Jul 2008
    Posts
    127
    Location
    South Eastern PA
    Tractor
    Kubota L3400HST

    Default Re: Reversed battery polarity on 8N

    <quote>By the sounds of it, my starter motor is running backwards at this point</quote>

    Unless there is a starter motor out there that stays engaged all the time, not likley. There are groves on the shaft that spin a cog into the flywheel. So if it ran backwords, the start motor wouldn't engage and it would never turn the motor over.
    Jim


    ------------------------------------------------------

    Life is too short to think about all the things you want to do, just go do them!

    Kubota L3400-HST with - LA463-1 FEL, Woods BH80x, Landpride 72 Landscape rake, Farm Force Middle buster, FF Tow rig, CA 42" pallet forks, CA 60" xtreme duty tooth bucket, KW manufacturing 84" dozer blade, with hydraulics.

  5. #5
    New Member
    Join Date
    Jun 2009
    Posts
    4

    Default Re: Reversed battery polarity on 8N

    Gotcha. So my starter motor is likely okay. Good to know.
    Thanks again.

  6. #6
    Elite Member kebo's Avatar
    Join Date
    May 2006
    Posts
    2,714
    Location
    Lexington, SC
    Tractor
    2001 John Deere 790 4x4, bar tires

    Default Re: Reversed battery polarity on 8N

    I'd almost be willing to bet there's not too much damage other maybe a blown fuse or three, and maybe a couple wires that have burned themselves in two. The first thing I would check would be all the fuses, including a fusible link if it has one. Then, I would trace all the wires that got hot, those should be a clue as they were carrying the heavy current. I don't think you can really know what all else is damaged (if anything) until you make sure the fuses and wiring are good first. Good luck!
    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, 5 1/2ft Cultipacker, 5ft Sitrex finish mower, Leinbach PHD with 9" & 12" augers, Leinbach middlebuster, Leinbach #11 Field Cultivator, custom 3pt handi-hitch, clamp on bucket forks, Pat's Easy Change.

    It's not how slow you mow... it's how well you mow slow!!

  7. #7
    Veteran Member
    Join Date
    May 2009
    Posts
    1,616

    Default Re: Reversed battery polarity on 8N

    Reversing the battery polarity is not the happy thing to do. All components that are solid-state devices are asuredly blown. The Diodes in the Alternator and Voltage regulator are most likely cooked, the electronic ignition module; any thing on the instrument panel that is solid state may be gone too. Relays, motors and lights should be ok. Check for blown fuses and fusible links.

  8. #8
    Old Timer Soundguy's Avatar
    Join Date
    Mar 2002
    Posts
    51,823
    Location
    Central florida
    Tractor
    ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC

    Default Re: Reversed battery polarity on 8N

    Jim.. it's apparrent your not familiarwith ford electrics.

    our old starter motors spin the same direction no matter what polarity.. it's because the way the field is wired.

    same with the ignition coil.. it will spark either polarity.. ( though best to run at correct polarity for optimum spark )

    old n's had no alternator.. only a generator.. and they can run either polarity once polarized correctly.

    now.. any alternators present are likel toast nearly instantly.. as is any ei modules if they were powered at the time the polarity swap happened.

    soundguy

    Quote Originally Posted by Lil_FarmerJim View Post
    Hey Frontman,
    I don't know about the 8N specifically but in general when you reverse polarity in a DC system you will cook anything that is dependent on a negative (or positive) ground , such as start motors, coils, etc. since they are dependent on the flow of electrons from only one direction. (Starter motors because power flowing the wrong way will run it in reverse) And the alternator, could be effected as its a similar to a electric motor and power flowing in the wrong direction might cause it to cook the internal wire windings as it fights to turn

    As for the fuses, they blow when the power traveling over the filament is more than its rated for.

    So if the motor cranks but you get no spark, I would check the ignition coil and see if it looks cooked. If its an electronic ignition, then I would bet that it's done for. The alternator would be the place I would look if the battery failed to charge or ran down after running it for a while.

    HTH

  9. #9
    Gold Member
    Join Date
    Mar 2009
    Posts
    431
    Location
    Lampasas, Tx
    Tractor
    Kubota L2800

    Default Re: Reversed battery polarity on 8N

    Once, when replacing the battery in an old 8N, I realized it was hooked up bass-ackwards... positive to ground... I'm not terribly smart but I had never seen anything like it so I set the new battery aside while I investigated... as it turns out, some are reverse polarity on purpose... it's just how the system was wired... Someone once told me that the only thing on the engine that care was the solenoid.... I installed the battery just like the old one against everything I had ever been taught and it works fine... jest looks funny.. lol
    The Dougster in the Great Republic of Texas

  10. #10
    New Member
    Join Date
    Jun 2009
    Posts
    4

    Default Re: Reversed battery polarity on 8N

    If I end up with just having to replace a few wires and fuses I'll consider myself lucky. I'll start on that tracing first and then I'll see about the alternator. I won't get a chance to check it now until Saturday but I'll post my findings.
    Thanks all...

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2016 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.