6v8n generator connections (2024)

May have too many layers of paint to see stamping.

Nick horse said:

on my 1952 8n the stud closest to block is wired to ground on the voltage regulator. In a You tube video on how to Motor a 8n 6v positive Ground generator which looked just like mine the stud closest to the block was called field and used as field to motor the gen. Video showed jumper wire from field to ground then another jumper hot wire to arm stud on back.
Has my gen been wired wrong all these years? Can the connections on the gen be reversed if wires to the voltage regulator are reversed also? Can’t see where the wire connection studs on the gen are labeled as field and ground?

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If you look CLOSELY at the terminal studs, the GROUND stud should NOT have any insulating washer on it, and the flat and/or lockwasher will be in direct contact with the "belly", and the washer(s) on the FIELD stud will be insulated from the "belly" by a fiber washer.

If you get a little deeper into it, the FIELD stud will have an insulating sleeve on it where it passes through the "belly" while the ground stud will not.

IIRC, hole in the "belly" for the FIELD stud will be a little larger to accommodate the insulating sleeve. I'm NOT 100% positive on that, though.

To be clear, the generator is mounted on the LH side of the block (correct for a late 8N), right?

Nick horse said:

Yes the generator is located on the left hand side. Side mount distributor on right side. i can’t see an insulating sleeve Which doesn’t mean it’s not there. I have looked for that before. Both studs are same diam. Tractor not running with meter set on highest ohms both studs show 0 ohms to gen housing. That seems strange to me if the field stud should be insulated from housing. Insulating sleeve dry rotted? I have run this tractor for 25 yrs with same charging parts. It always had a tendency to boil water out of the battery. wonder if was rebuilt long ago and the field and ground changed but I don’t know what’s inside to know if that’s even possible. ?

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What range do you have your Ohmmeter set on?

Since this is an "A circuit" generator when you measure Ohms to ground on the "F" stud you are measuring the resistance of the field coils, probably only an Ohm or two.

Nick horse said:

Thanks Ok I rechecked Setting ohms to 200 range and get 1-2 ohms on stud closest to block. Negligible to slight reading on stud farthest from block. My meter shows 1.1 ohms or so on zero or when leads are touched and kinda jumping around to find a stable reading but the one closest to block still seems to show 1-2 ohms. It seems like it may be wired wrong and correct is as Jmor image shows. If mine is wired wrong how did it work all these years?

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Nick horse said:

on my 1952 8n the stud closest to block is wired to ground on the voltage regulator. In a You tube video on how to Motor a 8n 6v positive Ground generator which looked just like mine the stud closest to the block was called field and used as field to motor the gen. Video showed jumper wire from field to ground then another jumper hot wire to arm stud on back.
Has my gen been wired wrong all these years? Can the connections on the gen be reversed if wires to the voltage regulator are reversed also? Can’t see where the wire connection studs on the gen are labeled as field and ground?

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Yes, Wore Out said it - The FIELD TERMINAL stud must be insulated and if you were wired backwards, unit would boil battery as JMOR said. Some GENS were labeled but not all were. The ARMATURE terminal is always on the back panel. ALL 8N's use the "A" Circuit Design in the generators in both the 3 brush and the 2-Brysh units. Only way to tell how it is wired for sure is by internal inspection - take to shop if in doubt.

Tim Daley (MI)

Nick horse said:

on my 1952 8n the stud closest to block is wired to ground on the voltage regulator. In a You tube video on how to Motor a 8n 6v positive Ground generator which looked just like mine the stud closest to the block was called field and used as field to motor the gen. Video showed jumper wire from field to ground then another jumper hot wire to arm stud on back.
Has my gen been wired wrong all these years? Can the connections on the gen be reversed if wires to the voltage regulator are reversed also? Can’t see where the wire connection studs on the gen are labeled as field and ground?

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OK, here are the facts on the 8N GENERATORS. This based on the MPC's, the original FORD TRACTOT editions, NOT the New Holland or aftermarket clones, as those all have errors in them. The 8N-10000 GEN, early 3-Brush Type, used 48-50, shows and lists the diagrams correctly as the GROUND TERMINAL (INNER) as being on the barrel closest to the Engine when mounted (pulley towards radiator) and the FIELD TERMINAL (OUTER) on the outside of barrel, and, the INSULATOR & TERMINAL STUD listed as p/n 81A-10206 and 81A-10208 for it. FORD was pretty good at drawings being as precise as possible so this data is correct. I've worked on many 8N's and their GENS and it was the early 3-BRUSH ones that were not stamped FLD & GRN on barrels. My early 8N is an example. Part MPC's and F0-4 manual details wiring and the VR and the OEM color codes shown. The Exact-As-Original Wiring Harness has the correct colors, OEM cloth covered, wiring to original spec lengths - I have one and it is all correct. NOW, be advised that yours may not be the original and most new vinyl wiring harnesses sold today are NOT correctly color coded so never use color as a guide. Colors don't conduct electrons. Finally, UTOOB has a lot of wrong misinformation so avoid using those videos if possible. You can watch them just don't put much into them. A few are OK - the "Wrenching WIth Rachel" videos are correct.

OEM Wiring Color Codes for VR and GEN:

GEN FLD to VR = BLACK with WHITE TRACER
GEN GRN to VR = BLACK with RED TRACER
GEN ARM to VR = YELLOW with BLACK TRACER

8N-14401-B WIRING HARNESS for 8N-10000-A; 3-BRUSH & FRONT MT DIST

SPARK PLUG WIRING:
#1 = 9N-12287-B; 17.5" LONG, BLK w/RED "X" TRACER
#2 = 9N-12284; 24.5" LONG, BLK w/BLUE "X" TRACER
#3 = 9N-12283; 27.5" LONG, BLK w/GREEN "X" TRACER
#4 = 9N-12286; 33.0" LONG, BLK w/YELLOW "X" TRACER

Tim Daley (MI)

Thanks Tim. I think your picture with fld terminal toward outside is correct on my particular gen. Although washers on both connections are hard like metal no amount of scraping shows the washer on the outside connection to be conductive. So I’m leaving things as is. Couldnt get the nut loose to take the belt off gen so while it was soaking in wd40 I scraped around on washers. Started the tractor and the voltage output was fluctuating from 3-16 v. I was really trying to hold a steady connection on meter so I guess that is the vr kicking in and out. I don’t have experience checking one that for sure is working correctly to know. Like I said this one always put a little much V in the battery which made me question the wiring which didn’t match most pictures I found.

block serial no. Shows it be 1952 8n. From your last post the gen appears to be 1950. The 1952 supposedly has a 4 speed trans but mine is 3 speed. Gen is black. Don’t know what color the originals where. I got the tractor in 1999 and it has served me well. Thanks again NH

Nick horse said:

Thanks Tim. I think your picture with fld terminal toward outside is correct on my particular gen. Although washers on both connections are hard like metal no amount of scraping shows the washer on the outside connection to be conductive. So I’m leaving things as is. Couldnt get the nut loose to take the belt off gen so while it was soaking in wd40 I scraped around on washers. Started the tractor and the voltage output was fluctuating from 3-16 v. I was really trying to hold a steady connection on meter so I guess that is the vr kicking in and out. I don’t have experience checking one that for sure is working correctly to know. Like I said this one always put a little much V in the battery which made me question the wiring which didn’t match most pictures I found.

block serial no. Shows it be 1952 8n. From your last post the gen appears to be 1950. The 1952 supposedly has a 4 speed trans but mine is 3 speed. Gen is black. Don’t know what color the originals where. I got the tractor in 1999 and it has served me well. Thanks again NH

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OH, well a 3-SPD says it is a 9N/2N tractor, at least the trans is. Forget any s/n -means relatively nothing. What is important is if a FRONT MOUNT or SIDE MOUNT DISTRUBTOR and you don't tell us. Now you COULD have a late 8N engine in it. MIN (More Info Needed) . Don't assume because you have a 6V battery the system is wired correctly for the OEM 6V/POS GRN setup. The 9N/2N wiring was different than the later 8N's and up. The 9N/2N uses a 6V/1-WIRE/3-BRUSH/11.5 AMP/'A'CIRCUIT GEN and the ROUNDCAN CUTOUT CIRCUIT. NO VR. The 8N revised system to a 6V/3-WIRE/3-BRUSH, later a 2-BRUSH/11.5A, later a 20A unit/'A'CIRCUIT GEN with a VOLTAGE REGULATOR. VR has 3 TERMINALS - ARM - FLD - BAT. Short FLD to either one of the other will fry the VR. VR p/n is 8N-10505-C. WE now need to know exactly what you are setup with. If you have a late 8N with the side dist, that changes things and whether a 3-SP or a 4-SPD trans matters not a bit; trans has nothing to do with the electrical system. Do not be swapping out any wires. Help is on the way...

Tim Daley (MI)