# 12 Volt 8N



## Glen640

I am not smart enough, electrically, to figure this out. Could use your help.

I replaced my old 8N (now for parts) with another one a couple of years ago. It has started OK but the battery died and I just replaced it. The previous owner told me that an earlier owner converted it over to a 12 volt system. I assumed that since a red cable ran from the positive post to the solenoid that he had converted it to negative ground as well.

I bought a new 12 volt battery, replaced the positive terminal and hooked everything up. When I hit the ignition button, a large spark occurred from under the hood, on the left side (from the seat facing forward) where the solenoid, starter and generator are. Thereafter, each time I hit the ignition button, I get a single click at the solenoid. Nothing else.

I didn’t have anything to go on as to what the proper battery should be so I just used the dead battery notations – Group 26, 525 CCA. I couldn’t match it exactly. Got Group 26, 550 CCA.

Any thoughts as to what might have happened and to do next?


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## Ed Williams

I use a standard 24F Ford battery on my converted NAA. It should be a neg ground system. Most likely the gen is still wired like a positive ground, or through an existing 6 volt regulator which is not needed on a 12 volt system, thus running straight to ground. Thus the spark. 

Yesterdays Tractor has several variations of wiring diagrams for 12 volt conversions that can be down loaded. Start at ground zero, the battery, and trace the wiring system. Somewhere you will find the grounds are crossed. You may also have damaged the battery or other electrical parts.

Good luck and report on progress,


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## BinVa

Glen640 said:


> I am not smart enough, electrically, to figure this out. Could use your help.
> 
> I replaced my old 8N (now for parts) with another one a couple of years ago. It has started OK but the battery died and I just replaced it. The previous owner told me that an earlier owner converted it over to a 12 volt system. I assumed that since a red cable ran from the positive post to the solenoid that he had converted it to negative ground as well.
> 
> I bought a new 12 volt battery, replaced the positive terminal and hooked everything up. When I hit the ignition button, a large spark occurred from under the hood, on the left side (from the seat facing forward) where the solenoid, starter and generator are. Thereafter, each time I hit the ignition button, I get a single click at the solenoid. Nothing else.
> 
> I didn’t have anything to go on as to what the proper battery should be so I just used the dead battery notations – Group 26, 525 CCA. I couldn’t match it exactly. Got Group 26, 550 CCA.
> 
> Any thoughts as to what might have happened and to do next?


Sounds like the starter has shorted. And at this point the solenoid is probably shot.
If you simply replaced the battery and hooked it up the same(which worked fine before the swap)then the only high voltage should be at the starter when the solenoid is excited. B.


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## Glen640

Glen640 said:


> I am not smart enough, electrically, to figure this out. Could use your help.
> 
> I replaced my old 8N (now for parts) with another one a couple of years ago. It has started OK but the battery died and I just replaced it. The previous owner told me that an earlier owner converted it over to a 12 volt system. I assumed that since a red cable ran from the positive post to the solenoid that he had converted it to negative ground as well.
> 
> I bought a new 12 volt battery, replaced the positive terminal and hooked everything up. When I hit the ignition button, a large spark occurred from under the hood, on the left side (from the seat facing forward) where the solenoid, starter and generator are. Thereafter, each time I hit the ignition button, I get a single click at the solenoid. Nothing else.
> 
> I didn’t have anything to go on as to what the proper battery should be so I just used the dead battery notations – Group 26, 525 CCA. I couldn’t match it exactly. Got Group 26, 550 CCA.
> 
> Any thoughts as to what might have happened and to do next?


I guess I am at a more basic level right now. If the only thing I did was to replace the battery, why would I have had a problem (of any kind)? It started and ran fine before the new battery.


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## pogobill

I don't follow the "Replaced the positive terminal"? Do you mean you replaced the cable from the battery to the starter, or just hooked the positive battery cable to the battery?!?
Check your connections to make sure they are tight and making good contact. Don't understand the spark business, but make sure there are no wires touching each other at the starter / solenoid. If the battery hasn't shorted, make sure you have it fully charged and try and start the tractor again. If you get a click, just tap the starter solenoid with a screw driver handle when pressing the start button. Not too hard or you'll crack the black plastic / bakelite housing.


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## Glen640

In my lingo, the terminal is the metal piece, connected to the cable, with a hole in the center that fits over the battery post. Since the original one was badly corroded and the bolt and nut were spinning free, I replaced it. Same cable. Same connections.

Performed all the functions you have suggested and no spark this time but still just a click at the solenoid. Battery is good.


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## pogobill

Just a quick thought.... I had the same thing happen to me yesterday. Check all the connections and all were tight, and no go. I checked the battery and had 6.8 volts (6 volt battery). Then I decided to check the battery voltage by putting the leads of the meter on the battery terminals, not the posts...... no power. A slight film of oxidation on the inside of the terminal was enough to give me a click, then nothing. I had also previously cleaned the battery posts with no luck.


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## Ed Williams

I don't know if this will help, but I apply a coating of dielectric grease I get from a local electrician who lives down the road right after cleaning the posts and terminals. It seems to prevent the lead oxidation problem while still allowing full current flow. Then after install I apply a layer of type 1 grease which is supposed to be more waterproof than the rest to both posts and terminals. Have not had any corrosion or starting problems since doing this. Good suggestion that came from my FIL who is a lifetime farmer.


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## Hacke

If you only switched batterys, and battery terminals, chanses are that something happened with the wiring. Old copper wires get hard and brittle and when you where dealing with them, something might have cracked. The spark may have left visible damage on the insulation or the connectors. If the battery cables look worn or are stiff, replace them.


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## Glen640

I had cleaned posts and terminals with brush and applied grease then too. I tested the terminals (per Bill) and got same reading as with post testing. Also ran test against neg terminal and positive cable connector at the solenoid and got same reading so current as far as to the solenoid is good. I will examine all the wires (per Hacke) when I start swapping parts. So before I start swapping solenoid (first) and starter (later) and fry another one, my last question relates to CCAs. Does anyone know if there is a CCA limit for 8N parts (solenoid/starter for example) ? As noted earlier, old battery was 525CCA; new is 550 CCA.


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## Hacke

https://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html#4
https://batteryuniversity.com/learn/article/lead_based_batteries
The higher CCA value, the better, no matter what vehicle the battery is on.

Do not just throw parts at it.
Of course it is possible that the starter decided to give up just at the moment you tried your new battery, but go for the wiring first. There is a possibility that the solenoid housing had a crack in it and things moved and shorted the circuit when you moved the wiring, so check the solenoid. Was the solenoid and/or starter wet when the spark occured?


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## FredM

If you have a good set of jumper leads, why don't you hook up from battery positive to solenoid positive to bypass the existing positive cable, this will then show if the cable and solenoid is ok, it is just possible that the copper wires in the solenoid connector were on the way out (corroding) and with the higher CCA has caused the arc.

The clicking of the solenoid suggests not enough amperage is passing to the solenoid now and because of this, the hold in coil can't hold the soft iron core in the start position for the heavy contacts to make the circuit to the starter motor, (another cause of clicking in a solenoid is the heavy contacts have arced over time and don't allow a good contact for the power circuit, and another cause is the fine hold in wiring has gone open circuit, don't go this way yet), when a solenoid gets to the clicking stage, it is usually replaced.

I was going to suggest to bridge the two heavy contacts on the solenoid with a piece of steel or a heavy screw driver to check the starter motor, but seeing that your tractor is a gasser, this may be a bit dangerous because of the possible ignition of fuel vapours, so I would suggest if the above fails, remove the starter and use the jumper leads to spin the starter to check it out.

Your problem is simple


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## Glen640

Used the jumper cable suggestion from FredM but got the same result. Swapped out the solenoid for my for-parts 8N solenoid and that didn’t help. Checked wiring (as best I am capable of (electrically challenged, remember)) and it seems OK. Still getting a click when I engage starter button, under any scenario I have tried.


Not sure what is left to try so thank you to all for taking the time to offer up your suggestions about what to do. I appreciate it.


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## FredM

Remove the starter and use the jumper leads, hook the positive to the heavy pole on the "starter side"(take note) of the solenoid, hook the other end to the battery positive, hook the earth to the negative pole on the battery and with the other end of the jumper, make a good contact against the starter motor mounting flange, if you have a large vice, I would mount the starter in that to counter the torque reaction, otherwise place starter on the ground (not the dirt) and place heavy foot pressure on it to hold, hooking up to the starter side of the solenoid will bypass the solenoid and activate the starter if this is ok, if you don't get the starter to spin, then it will need servicing.

Just hold the jumper to the starter to get it to spin, and don't have the starter spin for an amount of time, over spinning can damage the commutator.


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