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Subject: 1952 8n electrical problem

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John Bear    Posted 04-08-2023 at 09:03:28 [URL] [DELETE]        [Reply] [Email]  
  • 1952 8n electrical problem
  • Good morning. I just joined the NTC today ad have a question to put out there. I have owned my 1952 8N for about 20= years. Did a complete engine rebuild two years ago to to take care of high oil consumption and fowling. It has been running great, but a week ago no start due to no spark while cranking; key switch on + push button switch. When I release the push button on the trani cover the plugs spark great as the engine makes a few more rotations. So, I by passed push button switch; same thing. Then by passed the key switch; same thing. There seems to be a bad ground somewhere. I tested the coil, condensor, points, cleaned and gapped, etc... - all good. Any sugestions? Thanks, John B.

    Tool Pro    Posted 04-10-2023 at 07:13:07 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 1952 8n electrical problem
  • HiYa John- Welcome aboard. The important things are if you are using the original 6V/POS GRN Electrical system or a 12V conversion, either way, wiring each is different and must be correct for whichever. The 2nd point is if using the front mount distributor or the later angle (side) mount distributor. Parts and wiring are a bit different for each as well. Model year means nothing so don't rely on a s/n or a guess. 99.98% of all non-starting issues are due to incorrect wiring. Sanding down the starter motor mounting surface on the block and the starter motor itself are good so you maintain a good solid grounding connection. The 8N Ground Strap (+ POST) is designed to be fastened to the battery tray frame and works well - never any problems with me; p/n is 8N-14301, $22 at JUST8Ns. Sand down the bolt connection area too on the tray for same reason. Painted areas can cause failure to provide ground correctly. Having all the right manuals and documents also are a requirement. Switching back and forth between POS and NEG grounds can cause issues too. Your GEN needs to be polarized for whichever setup you plan to use, BUT, that isn't your non-starting problem. Usually done at testing when GEN is rebuilt, you can perform the task in a minute using your Voltage Regulator - see picture. Note terminal connections; if you guess or mix up connections you will fry the VR. A simple motoring test of your GEN too will polarize it too as long as you connect it right using whatever grn you use. I&T FO-4 Service Manual required. Finally you must have a fan belt tensioning bracket attached whether if using 6V or 12V, a GEN or an ALT, otherwise you will never charge the battery and operate the water pump effectively. 8N Operator's Manual is required. Here's some scans of manuals and documents. Go to the How-To's and Manuals forums here.

    8N Wiring; Front Mount & Side Mount:

    8N Front Mount:

    8N Wiring after s/n 263843 w/side mount:

    Ground strap connection on battery tray:

    Proper Fan Belt Tension Must Be maintained:

    Polarizing the GEN. NOTE - All 8Ns use the 'A' Circuit:

    Bob in KS    Posted 04-08-2023 at 11:18:21 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem

  • 6 or 12 volt, generator or alternator?

    " When I release the push button on the trani cover the plugs spark great"

    Sounds like something is pulling down your ignition voltage.

    1. Check both battery cable connections at both ends, especially where ground cable connects to the frame.

    2. If ground cable connects up by the tool box, current has to go through several dash to frame connections that can be rusted. On my 8N I moved my ground cable to connect to the main frame down near the starter.

    3. If you have a 12 volt alternator conversion and are using a resistor in series with original 6 volt coil check for too much resistance in resistor. In that case the + to - posts on coil should have about 1 1/2 ohms and have a 1 1/2 ohm resistor between coil and switch. Some alternator conversion kits come with a resistor that is wrong value. Also check for broken or corroded wires and high resistance in on/off switch.

    4. If it is 12 volt a direct 12 volt no external resistor coil such as NAPA IC14SB would eliminate the resistor

    5. With negative ground the - post on coil goes to side of distributor, with positive ground the + post on coil goes to side of distributor

    John Bear    Posted 04-08-2023 at 14:01:11 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • Thank you for responding Bob. This is the original 6V neg ground system. Though I did rewire the complete harness a few years ago. Per your suggestion, I moved the + battery cable end to ground through the oil filter bracket bolt into the head. Made sure it is a clean contact. The battery reads 6.5 volts and the distributor reads 6.4 volts with points open. Again, no spark when pushing the interlock switch and nice blue spark for the few engine revolutions after I release the switch. I am still suspecting the interlock, or possibly the voltage regulator which that switch is wired to?
    Thank you, John.

    Bruce(VA)    Posted 04-08-2023 at 11:16:21 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • Sounds like low voltage to me.

    A fully charged battery is 6.35 volts. Get out your meter. You should see 6.35 volts from the battery to the open points.

    Do you?

    John Bear    Posted 04-08-2023 at 13:52:20 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • Hi Bruce, thanks for responding. Yes, I have 6.4 V at the distributor terminal and points open. From another posted comment, I also moved the battery (+) ground to the the oil filter bolt in the head to make sure there is good ground. Still no spark when pressing the interlock switch. Sparks only after I release switch while engine turns a couple more times. I am still suspecting the interlock switch or possibly the voltage regualtor which tat switch connects to? Thank you.

    Bruce(VA)    Posted 04-08-2023 at 13:59:24 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • The voltage regulator is not in the ignition circuit.

    When you press the neutral safety switch, it grounds the solenoid. When the solenoid is grounded, the bendix engages the ring gear.

    Put the tractor in neutral. Turn the key on. Ground the small wire on the BACK of the solenoid to the block w/ a screw driver. What happens?

    John Bear    Posted 04-08-2023 at 14:11:13 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • With key switch on and the small solenoid terminal grounded to block; The the starter cranks the engine and plugs have no spark until the final few spins after I release the solenoid ground.

    Bruce(VA)    Posted 04-08-2023 at 14:39:09 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • Put your meter in-line with the starter stud. What voltage do you see w/ the solenoid engaged? ie, starter turning.

    John Bear    Posted 04-08-2023 at 15:16:17 [URL] [DELETE]        [Reply] [Email]  
  • Re: 1952 8n electrical problem
  • Gentlemen: I found the problem - self inflicted. I recently had the starter off to clean and service it. It was running great till I did that. So, I just retraced the wires and found that I had also connected the ammeter wire together with the interlock switch terminal on the solenoid. So, apparenly was also grounding the iginition when I pushed the interlock. I have great spark again and will start her up. Hope I don;t get kicked off the site for this one... Thank you for your time and advice, John.

    Bruce(OR)    Posted 04-09-2023 at 12:59:33 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 1952 8n electrical problem
  • That there be a "Stupid Human trick".
    Generally those are fun to watch on the 5 0'clock news.
    Kinda like the guy with the 50 foot bungee cord off the 40 foot building.
    That gives the res of us "Cheap Entertainment" while watching the 5 o'clock news.

    I have a whole slew of stupid human tricks.
    Listening to my wife has gotten some of the biggest ones yet.

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