8N10000 generator 8N10505 A or B regulator?

[Dave G9N]

My daughter and I have a 9N and two 2Ns. One of the 2Ns has a generator, the others have 12V conversions.

The generator on the 2N appears to be an 8N10000A since it has two side terminals and an adjusting screw. When she bought it, it had an 8V battery and a funky old rusty regulator of unknown pedigree. I plan to replace it with an 8N10505B unless someone can tell me why it is a bad idea. All of the wiring needs to be replaced.

I have not opened the generator up to see if it has been modified to cut out the third brush. It appears that a 8N10505B should work according to JMOR, the 8N10505B will function just fine with the 8N10000A generator. Another post where JMOR posted a copy of Service Bulletin 78 says that the 8N10505B can only be used if the "Field Correction" has been performed.

Looks like I need to open up the generator and look for and move the field lead to the negative brush. Is that right?

I tried to piece together the differences between the various generators. I made a table that puts it all together, but the preview show that spaces and tabs will be scrambled if I post it.
https://forums.yesterdaystractors.com/viewtopic.php?p=5074622 JMOR says 8N10505B is OK
https://forums.yesterdaystractors.com/viewtopic.php?p=5549356
https://forums.yesterdaystractors.com/viewtopic.php?p=2108548
https://forums.yesterdaystractors.com/viewtopic.php?t=338012
https://forums.yesterdaystractors.com/viewtopic.php?t=1440607 Post with service bulletin
https://forums.yesterdaystractors.com/viewtopic.php?t=1512647
https://forums.yesterdaystractors.com/viewtopic.php?p=8848838 Adjustment

 

[JMOR]

(quoted from post at 18:10:44 11/19/22) My daughter and I have a 9N and two 2Ns. One of the 2Ns has a generator, the others have 12V conversions.

The generator on the 2N appears to be an 8N10000A since it has two side terminals and an adjusting screw. When she bought it, it had an 8V battery and a funky old rusty regulator of unknown pedigree. I plan to replace it with an 8N10505B unless someone can tell me why it is a bad idea. All of the wiring needs to be replaced.

I have not opened the generator up to see if it has been modified to cut out the third brush. It appears that a 8N10505B should work according to JMOR, the 8N10505B will function just fine with the 8N10000A generator. Another post where JMOR posted a copy of Service Bulletin 78 says that the 8N10505B can only be used if the "Field Correction" has been performed.

Looks like I need to open up the generator and look for and move the field lead to the negative brush. Is that right?

I tried to piece together the differences between the various generators. I made a table that puts it all together, but the preview show that spaces and tabs will be scrambled if I post it.
https://forums.yesterdaystractors.com/viewtopic.php?p=5074622 JMOR says 8N10505B is OK
https://forums.yesterdaystractors.com/viewtopic.php?p=5549356
https://forums.yesterdaystractors.com/viewtopic.php?p=2108548
https://forums.yesterdaystractors.com/viewtopic.php?t=338012
https://forums.yesterdaystractors.com/viewtopic.php?t=1440607 Post with service bulletin
https://forums.yesterdaystractors.com/viewtopic.php?t=1512647
https://forums.yesterdaystractors.com/viewtopic.php?p=8848838 Adjustment

easure circumference of the generator barrel. You might have something rare, if it measures 11 1/2 inches.....it will not work with 8N 10505 reg, but those very early 3 terminal gens are much sought after by collectors. If it measures 14 1/4 inches , then it probably is 8N1000A and then follow the instructions in serv bulletin 78, as attached.

 

[Tim PloughNman Daley RIP]

Dave & Daughter-
FYI: ALL 9N & 2N GENERATORS after s/n 12500 were a 1-Wire/3-Brush, 11 AMP, 'A' Circuit Design, unit and required the ROUNDCAN CUTOUT CIRCUIT -NO VR. Only the first
early 9N GEN had 2 Wires and were 2 Brush so NO 3rd Brush Adjustment screw -this was the small barrel, 7 AMP GEN, 9N-10000-A. ALL 8N GENERATORS used 3 WIRES, two on
the barrel (FLD & GRN) and one on the back panel, ARMATURE connection, and a Voltage Regulator. Early 8N GENs were 3-WIRE/3-BRUSH, 11 AMP. 'A'Circuit Design, then
later changed to a 2-Brush Unit then went with the side mount distributor and a 2-Brush/20 AMP unit. FORD offered a Service Bulletin with instructions on how to
install an 8N GEN & VR on a 9N/2N. I have a copy if you want - email is open. FWIW, why an 8V Battery??? It does nothing. It'll never charge. This is one of the many
myths/fallacies surrounding these N's...

A 9N/2N using OEM 6V/POS GRN requires:
6V GRP 1 Battery
1-WIRE/3-BRUSH GEN, 11 AMP
Round-Can Cutout
1-Wire Starter Motor with NO Solenoid
Ballast Resistor
AMMETER
IGN SWITCH
Start Pushbutton

Note the OEM Ballast Resistor must be used in BOTH the 6V and a 12V setup.

Ford n-series tractor wiring & pictograms:

NOTE: 12V using 6V Coil Requires extra in-line 1-OHM Resistor as shown.

FORD 9N/2N TRACTOR (AFTER s/n 12500) WIRING DIAGRAM:

FORD 8N WIRING SCHEMATIC:

FORD EARLY 8N GENERATOR 3-WIRE/3-BRUSH 11 AMP UNIT:

***PICTOGRAMS courtesy of JMOR



Tim Daley(MI)

 

[Dave G9N]

(quoted from post at 05:13:21 11/20/22) Dave & Daughter-
FYI: ALL 9N & 2N GENERATORS after s/n 12500 were a 1-Wire/3-Brush, 11 AMP, 'A' Circuit Design, unit and required the ROUNDCAN CUTOUT CIRCUIT -NO VR.

FORD offered a Service Bulletin with instructions on how to
install an 8N GEN & VR on a 9N/2N. I have a copy if you want - email is open. FWIW, why an 8V Battery??? It does nothing. It'll never charge. This is one of the many myths/fallacies surrounding these N's...

Note the OEM Ballast Resistor must be used in BOTH the 6V and a 12V setup.
NOTE: 12V using 6V Coil Requires extra in-line 1-OHM Resistor as shown.

Tim Daley(MI)

Thanks Tim, I would like to see the service bulletin. If I figure out how to email, I will. Thanks also to JMOR.

I am sure that it is an 8N10000A generator. JMOR's picture of the original 9N10000 below shows only one side terminal.

I have tried to cobble together several quotes from different threads. The generator in question looks exactly like the grey one labelled 8N10000A with the two side terminals. It is not original. There is still an old cutout on the tractor that is no longer wired up. It did have a cutout and must have had a different generator.

Why 8V? The previous owner added the 8V battery and the cheap carburetor that will not go uphill. It stalls on any slope over say 5, but has no problem backing uphill. I suspect the float is sticking, based on internet expertise (ignorance informed by unreliable...) I want to get the electrical system working properly before tackling the rest of the problems, one fried battery is bad enough.

It should never charge, but it did, possibly because it was malfunctioning just right. I was able to read 9V with a cheap digital meter by inserting a coil of galvanized lock wire between the ground and the meter lead. (Ground because it will short to everything it touches.) Somewhere between the induction, resistance and blind luck, the wire filtered the noise and the meter stopped bouncing around. The battery did charge, but the decrepit wiring has some intermittent high impedance shorts, so it also tended to drain the battery while unattended and that killed the battery. My daughter bought a 6V to replace it. The tractor started with the 6V, but then decided to quit next day. Spark is good, it turns over, but isn't catching. So 6V works fine, but there are other issues.

(quoted from post at 14:29:02 03/26/12)

(quoted from post at 16:34:14 03/26/12) Can anyone tell me the difference between a early
8n voltage regulator and a late 8n voltage
regulator?

he early VR, (8N10505A), used with the 8N10000A generator with 3 terminals AND 3 brushes, with the 3rd brush adjustable via the HI/LO screw on rear bearing plate, had no current control, only voltage control......the operator set desired current with the HI/LO screw. The later VR, 8N10505B, used with the 8N10000B generator with 3 terminals and 2 brushes had no HI/LO current adjusting screw ....the VR provided BOTH current & voltage control. You can no longer obtain a 8N10505A VR (so far as I can determine),

quoted from post at 10:42:52 07/03/20) https://forums.yesterdaystractors.com/viewtopic.php?t=1440607

All 3 brush generators were used with cut out, EXCEPT for the first 8N generators which used a regulator & the generator had the necessary field terminal. Shortly thereafter the third brush was removed & at that point a different regulator was used.[/quote]
This post was edited by Dave G9N on 11/20/2022 at 03:04 pm.

 

[Tim PloughNman Daley RIP]

HiYa Dave -
On a post, in the lower RH corner you see the MSG: [REPLY] and either [NO EMAIL] or [SEND EMAIL] if the reply has entered his email address. Click on SEND and you get
a form from YT that you need to fill out and enter your message then send and I get an email with it so we can go from there. Can you post pictures and if not email
them to me in jpg format attachments? STOP probing your VOM and/or your Idiot Test Light - you may short out something. As JMOR and I detailed below, the 8N10000 GEN
has THREE WIRE CONNECTIONS: ARM - FLD - & - GRN. ARM is always on the back end plate. 3rd Brush Adjustment Screw is also on the back but many have rewired theirs for 2
BRUSHES so leave it alone, it is not the root cause problem. The 9N-10505-A CUTOUT is used on all 9N & 2N models after s/n 12500, and used a 1-WIRE/3-BRUSH, 11 AMP
unit. The 8N introduced the 3-WIRE/3-BRUSH 11 AMP unit and now used the 8N-10505 Voltage Regulator. They are two different components. The Cutout is NOT a VR and the
VR uses a cutout built-in. FACT: 99.98% of all non-starting issues are due to incorrect wiring. As far as an 8V Battery goes, ...It should never charge, but it did,
possibly because it was malfunctioning just right.... NO, physically not feasible. How can a 6V GEN produce 8 or 9 VDC? If you applied a std garage 12V trickle
charger, you probably boiled out the battery anyway now and it cannot be fixed. Best advice I can give is to get the wiring correct first, with OPTION #1, get a 2N GEN
and CUTOUT or revamp the 8N GEN with my SB I will send you. OPTION # 2 is to switch to 12V and eschew the CUTOUT, VR, and GEN altogether. Use JMOR's WIRING PICTOGRAMS
for whatever system you choose and take no shortcuts. Whatever setup you use, the GEN and the ALT must have a belt tensioner device attached otherwise the unit will
never charge the battery. Once wiring is corrected and system is running normal, the last thing to consider is to invest in a float charger, NOT a trickle charger. A
float charger will maintain optimum battery performance, fully charged, so it is ready to go when you are. The DELTRAN BATTERY TENDER is a very good product. The JR
model is the 6V style. $30 typical. EMAIL ME and I will also send you a copy of my FORD N-SERIES TRACTOR GENERATOR & VR DOCUMENT.



TPD

 

[Dave G9N]

It took a while to figure out, but the reply option only shows up in classic view. Could be a browser issue?

I bought an 'AUTOUTLET 6/8/12/14/24V Battery Charger' on Amazon for $40. It is a little yellow box with small wires that does not inspire confidence, but turns out to work very nicely. You hook up, turn on and scroll to the correct voltage, then select fast charge or smart charge. It does go to float once the battery is charged.

Half of what I am about to say I learned from you and or JMOR, so feel free to correct me. A generator puts out variable voltage depending on the rpm. As the rpm increases the generator voltage reaches the threshold voltage set by the cutoff, it connects the generator to the charging circuit (either the 9N cutoff or the one inside the regulator). When the voltage reaches the upper limit for charging, another solenoid in a regulator starts chopping the output to regulate the effective voltage. (OK, at this point, I may be exceeding my level of 'expertise') The adjustment screw on the 9N generator increased the voltage, so it should only used when the lights were use. The chopper operates at a lower frequency than the digital meter, so the meter is trying to display instantaneous voltages rather than average. The 6V generator can produce 9V but the rpm range for charging will be higher than for 6V. If the regulator is working properly, it should not charge an 8V battery, and adjusting it is reported to be difficult. The seller was an old car buff who pulled it out of the ditch where it died and got it running to help the elderly previous owner unload it. Could be a cock and bull story. He clearly had a lot more belief than understanding when it came to voltage and regulators. I suspect it is a 12V regulator which is acting as a cutoff only because the 6V genny maxes out at 9 or so. Could be wrong.

Since I intend to revamp the 8N generator and put in the correct regulator, it isn't important how it worked. The revamped 8N should put out more amperage and we won't have to search for another generator. Mary bought a new wiring harness, so we are starting from scratch on the wiring anyway. The old wiring is shot. Cracks, corrosion, multiple splices wrapped in tape, no old wire ever removed, just bypassed. I hope the 9-24V LED headlights that worked on the 8V kluge will work on 6V, but have other uses for them if not. They fit inside the original housings, but look wrong. Perhaps a lens cover will hide them.

The VOM does have some uses, I did find the loose rivet that caused the intermittent open on the ballast resistor. a new pop rivet was all it needed. But yes, you have a good point.

 

[Tim PloughNman Daley RIP]

I don't use Modern View, don't see any advantage and to me only adds to the confusion when posting.

ALL 9N/2N (after 1940) and early 8N 6V GENS have an 11-AMP output so an 8V battery isn't going to increase the output any, and as mentioned, will never charge an 8V battery. 12V wasn't used til the late '50s and only on diesel models so depending on where you bought from, check the part number they gave you but it isn't your problem. The later 8N used a 2-Brush/20 A Unit but that was when FORD went to the side distributor so terminals are mirrored on them. I will send you my GEN DOCUMENT and you can get the true full story. Bottom line is there were many issues with early GENS. There Brushes were tried at first. Increasing the 3rd Brush was advised only when lights were used, but reduced when not in use so as not to overcharge the battery. It wasn't the root cause problem. Forget messing with ADJ SCREW, leave it on LOW. If you do have a later 12V VR, maybe consider getting your 8N GEN rewired to 12V and a 12V battery. If staying with your 3-BRUSH 8N GEN use the VR 8N-10505-B.

Tim Daley(MI)

 

[Dave G9N]

I sent an email. Tried to anyway.

I plan to follow service bulletin 78 and get the 8N10505B regulator. I read through FO-4 and wish I could claim to understand what I am talking about. FO-4 did say that the adjusting screw changes both voltage and amperage in paragraph 70. First thing to tow it home and push it into the garage before the snow is too deep. It is 10 miles away in an open field and working in the open in a Minnesota winter is hard on old fingers. It isn't even properly cold yet.

I tried to list the various differences between the generators based on the forum discussions I could find. There are some gaps and If anyone sees anything wrong, let me know and I will fix it.

 

[JMOR]

(quoted from post at 02:18:28 11/23/22) I sent an email. Tried to anyway.

I plan to follow service bulletin 78 and get the 8N10505B regulator. I read through FO-4 and wish I could claim to understand what I am talking about. FO-4 did say that the adjusting screw changes both voltage and amperage in paragraph 70. First thing to tow it home and push it into the garage before the snow is too deep. It is 10 miles away in an open field and working in the open in a Minnesota winter is hard on old fingers. It isn't even properly cold yet.

I tried to list the various differences between the generators based on the forum discussions I could find. There are some gaps and If anyone sees anything wrong, let me know and I will fix it.

hart is unreadable for starters & where did it come from?

 

[Dave G9N]

(quoted from post at 23:22:56 11/22/22) chart is unreadable for starters & where did it come from?

compiled the information from the posts that I listed in the first post on this thread. It is a screenshot of an Excel file that I made up. It looks OK on my 17" screen but rather small and does not blow up well.
Is this one any better?
This is a new chart. No point in multiple copies.

JMOR's picture night help

This post was edited by Dave G9N on 11/23/2022 at 01:11 pm.

 

[Tim PloughNman Daley RIP]

Pretty straight forward stuff. The first TWO generators, the 'A' and the 'B' suffixed ones, small barrel, 7 AMP output. The A was 2-Wire/2-Brush BCircuit and required
a VR, the B was 1-Wire/3-Brush, A Circuit and used the roundcan cutout. The 'B' used a HI-LOS slider button for 3rd Brush ADJ. The 9N-10000-C was a 1-Wire/3-Brush, A
Circuit, 11.5 AMP unit with a larter barrel and now had a 3rd Brush LOW/HIGH adjustment SCREW and used the cutout. This design would remain the same until end of 2N
production in 1946, except when the 2N-10000 model was released that now had the belt tensioner but the unit was virtually the same otherwise. GENS reamined 11 AMPs til
the 8N-10000-B then 20 AMPS became the std and used all thru Hundred Series. Email me for the complete true story I wrote.

Tim Daley(MI)

 

[Tim PloughNman Daley RIP]

resend me your msg with your email so I can send you my GEN DOCUMENT --- deleted original in error

TPD

 

[JMOR]

 

[Dave G9N]

Thanks JMOR I used the note you posted to update the table. There are a few things that I suspect are not quite right because they don't match the picture you posted in 2020 and I copied to the edited post with the updated table. So here I am correcting the person I learned much of this from based on what I think I understood.

I looked up the inner workings of voltage regulators. Rather than butcher a long description, here is the link:
http://www.secondchancegarage.com/public/83.cfm
The part that I understood was "they are exceedingly hard to adjust."

 

[Abbby]

Dave G9N. Unless you are trying to keep it original just convert tractor to 12 volt. Seems you are having to replace all electrical so at this point just modernize it.

 

[Dave G9N]

(quoted from post at 04:43:46 11/24/22) Dave G9N. Unless you are trying to keep it original just convert tractor to 12 volt. Seems you are having to replace all electrical so at this point just modernize it.

here are reasonable arguments both ways about 6 vs 12V. For long term simplicity, cost and ease of operation and purchasing lights, etc, 12V is the only way to go. Most 6V 9N and 2N generators have inadequate amperage for incandescant lights without playing games with the adjustment screw, on those models that have them. The more elegant solution with the one wire cutout generator would be 6V LED bulbs, which are available. The more practical utilitarian option is of course the 12V alternator.

I just want it working. Mary already bought a new 6V battery to replace the dead 8V plus a new wiring harness, which probably needs a few more wires for this generator. I haven't counted the wires yet. The generator is working, but the voltage regulator is of unknown provenance and too rusty to make good contact. If the new 8N10000B regulator turns out to be a short lived piece of junk, we will go 12V.

For short term, in order to get this 2N tractor with an 8N gennerator and engine running with minimal effort, it looked to me like a regulator or cutout was all that was needed if only we could identify the generator. There was conflicting advice on this forum concerning the A or B rev of the regulator, which is why I asked.

It turns out, as I have learned here thanks to Tim and JMOR, the generator is an 8N10000A. If it has not been upgraded in accordance with Service Bulletin 78, the correct regulator would be an 8N10500A, which can only be purchased as an Autolite VRR 4008A. The Autolite regulator costs more than the alternator conversion kit available on this website plus the cost of a new battery. Since I have a 9N and 2N with 12V alternators to look at, I can see that there isn't a lot of work involved installing brackets. With the very simple modification per SB 78 involving moving one end of one wire inside the generator, the correct regulator is a $40 8N10505B (or a very expensive Autolite VAZ 4001A). The 6V headlights need new bulbs. The 9-30V LED headlights that fit inside the Ford headlights worked fine with 8V but do not work at 6V.

The summary that might help someone else here would be a list of which wiring diagram matches which generator. Since the generator often does not match the tractor and there were several generators used on each version of the N series, you need to go by the generator presently installed to determine how to wire it up. One more column needed on my little chart.

FWIW, one of the Autolite regulator ads said that the regulator will not survive charging a dead battery. I had a '93 [edit: oops, 1963 Saab 96] Saab 2 stroke with a generator in the early 70s. A bad battery killed the regulator. The damaged, but apparently functional regulator then damaged the new battery before it was obviously not working. The damaged new battery wasn't obviously bad until it damaged the new regulator which seemed to be working until after it wrecked the third battery. Point is, I highly recommend replacing both the regulator and battery at the same time. That's why I don't want to run the new battery with the old regulator.

This post was edited by Dave G9N on 11/27/2022 at 11:19 pm.

 

[JMOR]

(quoted from post at 20:33:25 11/26/22)

(quoted from post at 04:43:46 11/24/22) Dave G9N. Unless you are trying to keep it original just convert tractor to 12 volt. Seems you are having to replace all electrical so at this point just modernize it.

here are reasonable arguments both ways about 6 vs 12V. For long term simplicity, cost and ease of operation and purchasing lights, etc, 12V is the only way to go. Most 6V 9N and 2N generators have inadequate amperage for incandescant lights without playing games with the adjustment screw, on those models that have them. The more elegant solution with the one wire cutout generator would be 6V LED bulbs, which are available. The more practical utilitarian option is of course the 12V alternator.

I just want it working. Mary already bought a new 6V battery to replace the dead 8V plus a new wiring harness, which probably needs a few more wires for this generator. I haven't counted the wires yet. The generator is working, but the voltage regulator is of unknown provenance and too rusty to make good contact. If the new 8N10000B regulator turns out to be a short lived piece of junk, we will go 12V.

For short term, in order to get this 2N tractor with an 8N gennerator and engine running with minimal effort, it looked to me like a regulator or cutout was all that was needed if only we could identify the generator. There was conflicting advice on this forum concerning the A or B rev of the regulator, which is why I asked.

It turns out, as I have learned here thanks to Tim and JMOR, the generator is an 8N10000A. If it has not been upgraded in accordance with Service Bulletin 78, the correct regulator would be an 8N10500A, which can only be purchased as an Autolite VRR 4008A. The Autolite regulator costs more than the alternator conversion kit available on this website plus the cost of a new battery. Since I have a 9N and 2N with 12V alternators to look at, I can see that there isn't a lot of work involved installing brackets. With the very simple modification per SB 78 involving moving one end of one wire inside the generator, the correct regulator is a $40 8N10505B (or a very expensive Autolite VAZ 4001A). The 6V headlights need new bulbs. The 9-30V LED headlights that fit inside the Ford headlights worked fine with 8V but do not work at 6V.

The summary that might help someone else here would be a list of which wiring diagram matches which generator. Since the generator often does not match the tractor and there were several generators used on each version of the N series, you need to go by the generator presently installed to determine how to wire it up. One more column needed on my little chart.

FWIW, one of the Autolite regulator ads said that the regulator will not survive charging a dead battery. I had a '93 Saab 2 stroke with a generator in the early 70s. A bad battery killed the regulator. The damaged, but apparently functional regulator then damaged the new battery before it was obviously not working. The damaged new battery wasn't obviously bad until it damaged the new regulator which seemed to be working until after it wrecked the third battery. Point is, I highly recommend replacing both the regulator and battery at the same time. That's why I don't want to run the new battery with the old regulator.

ll except the very early VRs have current regulation as well as voltage regulation, so are not subject to damage by a bad battery or damaging a good battery.

 

[Dave G9N]

(quoted from post at 05:05:17 11/21/22) HiYa Dave -
Can you post pictures and if not email

EMAIL ME and I will also send you a copy of my FORD N-SERIES TRACTOR GENERATOR & VR DOCUMENT.
TPD

think you have answered all of my questions. I found 'Generator - The History of the Ford Ferguson 9N Tractor Generator, by Tim Daley" on the n tractor club howtos page. Very helpful. You guys did a lot of work on that.

You asked "How can a 6V GEN produce 8 or 9 VDC?"
The voltage is a function of rpm. I saw another thread where someone else got 9V too. The engine won't turn fast enough to make much more than 9, which is probably how the 8V fans scrape by. The VR in this tractor is something out of the previous owner's used parts bin. He told me that they somehow just seem to take care of it. I knew better than to try to argue at that point. I knew he was mistaken, but I didn't know enough to argue the point. It seemed to be working, I figured I could just get an 8V regulator, but never found one.

You also said that if you don't have a tensioner, the battery will not charge unless you stop and tighten the belt every hour. As you can see in the pictures below, the tractor does not have one [edit the belt would not stay tight, ]and you are correct it didn't charge after a while. We should have read your generator history before we killed the battery.

This is what the generator and VR look like. [EDIT: correcting diameter. Measured with a caliper it was 4 7/16 so this is a 4 1/2" barrel.] Some of the wiring has been replaced and a lot has been removed. It was working as shown in the picture, but the contacts are all corroded and tend to need jiggling. It all needs to be replaced. There is a cutout and there is a pickup truck starter relay fastened to the original relay.

Hopefully I got this one right. The schematics are all as labeled in the replies to this thread.

This post was edited by Dave G9N on 12/03/2022 at 11:32 am.

 

[Dave G9N]

(quoted from post at 05:05:17 11/21/22) HiYa Dave -
Whatever setup you use, the GEN and the ALT must have a belt tensioner device attached otherwise the unit will
never charge the battery.
TPD

i Tim,

I looked online for a tensioner, thinking it was the spring loaded clamp device used on earlier models. This tractor has the part of the tensioner still bolted to the head, so I thought it would be the earlier type. They are not available, except for some rusty incomplete ebay specials. I found another thread from last December where you posted pictures of the 8N10000A generator with the 8N-10145 belt tensioner arm. I went out and had another look at the tractor. The mounting holes are there, but the link is missing. It is available from Just 8Ns. It is just a short bar with two holes.

I drilled two 7/16" holes in a ~1/8" thick 1" wide bar about 2 5/16 on center and it fits. I had to clean off a lot of crud to find that the bar mounts to the next screw above the generator mount. The generator in the picture is from your answer to that post.

In case anyone is looking to make a spring loaded tensioner, and doesn't mind that it isn't proper restoration material, I found a part that can be used. A 4" riser clamp from the plumbing department at Menards (SKU is 6854571) is the right diameter for this generator and would work. I did a test fit, and it looks like it could have been made for this application.
EDIT:
I might as well update this with some pictures of what the tensioners look like and where they go. The clamp type can sometimes be found on ebay and there is one place selling the later link version. I had already made a substitute for the clamp on type before I saw how simple the link was and cleaned enough crud to see where it should go. I installed both to get a look and take a picture. The picture shows both just for illustration. You would use one or the other. The spring loaded clamp requires the 2N10178 Generator Mounting Bracket on Cylinder Head, which was already on my tractor. It should be simple enough to make a substitute.
These are the bracket options:

This shows them installed. If you have to replace the 3" mounting bolt, and the store has a 4", it will be very hard to tighten the nut on the link unless you cut the excess off. The DIY would look better painted.

This post was edited by Dave G9N on 12/06/2022 at 08:19 pm.