N Board Forum - Expanded Thread Page

Subject: 49' 6 volt positive ground cable HOT!

[Back] [Return to Top of Forum]

Harry    Posted 03-21-2020 at 11:43:45 [URL] [DELETE]        [Reply] [Email]  
  • 49' 6 volt positive ground cable HOT!
  • My wife brought me a non-running 1949 8N 6 volt home for Christmas last year to go with my 1950 12 volt. I'm new to the 6 volt positive ground world. My issue is that the positive ground gets so hot it smokes and burns your thumb if you happen to think, oh, I need to disconnect that.

    Work I have done. Replaced the coil with a 6volt coil, distrib cap and innards, rewired with a purchased harness and have checked the connections and diagram over and over. I put on a new resistor, I purchased a 6 volt battery and connected it just as it was when I got it and put in a new ignition key. It does have a functioning push button starter also.

    I have yet to hook up the fuel to attempt to crank it, but I am getting spark to the plugs. But something is wrong for that ground to get so hot. What advice or trouble shooting tips do you have? It is a polarity issue?


    Bob in KS    Posted 03-22-2020 at 09:40:34 [URL] [DELETE]        [Reply] [Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • Positive ground is not the problem.

    High heat in the ground cable indicates high resistance. Where is your ground cable connected?

    If connected to the battery holder frame work you have several bolted connections to go through to make a circuit down to the main frame at the starter. Any of those is a potential for corrosion and high resistance.

    A corroded or eroded battery terminal connection, or corrosion in the cable itself builds resistance.

    If it were mine I would install a known good cable from battery post to main frame as close to the starter as possible.

    Also check that the cut out relay in the voltage regulator is not stuck closed.

    Harry    Posted 03-25-2020 at 13:49:13 [URL] [DELETE]        [Reply] [Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • Alright, I am learning as I go gents. I went back and retraced my wires and found that I had swapped the B and the A wires on the regulator. When I put them on correctly the starter no longer turned over and I get a spark at the positive ground battery terminal and the solenoid clicks. I've checked the circuits with a tester (light) and every thing seems to be working and getting power where it should, ie, ignition button, key, coil etc. I'm at a loss on why I'm getting a single click. I have charged the battery to make sure it's fully charged.

    I'm curious if I burned up the coil, regulator or something.

    The battery cable is the proper gauge and appears to be serviceable but it is connected to the battery tray bolt, which I will move.

    I took some pictures and will try to load them, but I've to get a method to do so.

    Jack - Iowa    Posted 03-22-2020 at 07:26:16 [URL] [DELETE]        [Reply] [Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • I should add:

    If, when you pull the wires off of the first large post on the solenoid, your short does not go away, the heavy cable to that point is shorted to ground someplace.

    Jack - Iowa    Posted 03-22-2020 at 07:22:35 [URL] [DELETE]        [Reply] [Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • You have a serious short.

    Working Positive ground is no different that working Negative ground. It's a matter of labeling for troubleshooting. Have to reverse your meter leads.

    If your ground cable is getting hot, I would also expect one of the wires on the "hot" side to be hot also. Current has to have a complete circuit.

    Remove the battery cable and any other wires from the starter solenoid. Touch only the battery cable to the solenoid post. Sparks? IF so, remove the wires from the small post on the starter solenoid and try again. Spark? Remove the wire from the other large post and try again. Spark? Remove the solenoid and throw away.

    If no spark when you removed the wires from the small post, your problem is in that circuit. Pinched wire?

    Good Luck,


    Tim Daley(MI)    Posted 03-21-2020 at 12:20:10 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • NO! Battery cables or anything else except the ballast resistor gets that hot. You have mucked up wiring. Don't try to start with gas til it is corrected. Did you follow 'WIRING PICTIGRAMS by JMOR' from the HOW-TO's/ELECTRICAL from here? Here is a page for the 6V/POS GRN setups:


    *PICTOGRAM courtesy of JMOR

    Tim *PloughNman* Daley(MI)

    *9N653I* & *8NI55I3*

    Harry    Posted 03-21-2020 at 14:03:57 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • Tim,
    No worries on fuel. Safety first, retired military etc. I took the hood and tank off for better access. I did print the diagrams and felt like they were correct after multiple checks. That’s why I reached out to you guys to see if there was something I may not know about positive ground that could do it beside my “mucking” it up. If not, I’ll recheck my madness until I find it.

    mhb@ufe    Posted 03-21-2020 at 14:33:49 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • What size ground cable do you have? 6 volt systems require heavy cables due to the higher amperage.


    JMOR    Posted 03-21-2020 at 14:43:25 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • Hot uniformly along entire length or at one end or the other, more than elsewhere?

    Harry    Posted 03-22-2020 at 07:53:46 [URL] [DELETE]        [Reply] [Email]  
  • Re: 49' 6 volt positive ground cable HOT!
  • I had to step away from it yesterday and will try to get some more time with it today to sort it. I will let you know. I will also try Jack's trouble shooting. I appreciate all of the assistance!!!

    [Back] [Return to Top of Forum]