Need new voltage regulator.. S/G Belt

[FLtractor 219]

Afternoon,

Took my 856 K181 starter gen off tractor to local shop.. they tested it Said it works good and ran a belt on the pulley.. said will crank tractor long as battery charged. But it is not charging so need new voltage regulator Current regulator has 3 terminals front and underneath wire.. can’t find anything online based on the housing #”s. 
Also should get new S/G belt. Here is current belt and belt from Napa that supposedly fits. 

Edited September 24 by FLtractor

[953 nut 69,104]

Kohler 7hp, 8hp                                                      Kohler # 231605                                     3L-32   Notched raw rubber edges NAPA 25-7315

 

A fabric covered belt like that will not grip enough to start your engine.

[FLtractor 219]

23 minutes ago, 953 nut said:

Kohler 7hp, 8hp                                                      Kohler # 231605                                     3L-32   Notched raw rubber edges NAPA 25-7315

 

A fabric covered belt like that will not grip enough to start your engine.

Thank you for belt #. Interesting the # on Napa is a cogged belt unlike what’s on my tractor now.
regarding the Voltage regulator.. do you happen to know of a solar charger i could hook battery to if i decided not to get new voltage regulator?

Edited September 24 by FLtractor

[ri702bill 12,972]

Agreed - you need the raw sided cogged belt. It fits tighter on the S/G pulley and does not slip.

Did you attempt to diagnose your old Delco Remy Regulator? They are pretty simple...

[FLtractor 219]

25 minutes ago, ri702bill said:

Agreed - you need the raw sided cogged belt. It fits tighter on the S/G pulley and does not slip.

Did you attempt to diagnose your old Delco Remy Regulator? They are pretty simple...

Good to know about belt. Didn’t not attempt diagnosing regulator.. not sure how to do so or what to look for.. have link to good video by chance ?

Edited September 24 by FLtractor

[ri702bill 12,972]

1 hour ago, FLtractor said:

have link to good video by chance

Ha - that's funny. No - the info I have goes waaaay back. These files are a lot of knowledge, even with the corny illistrations. Remember that the origin of S/G systems dates back to the 1930's - almost 100 years ago.

 

 

Delco_Kohler_4-72_SM_Section_07.1-7.6_Starter_-_generator_HR.pdf Delco Remy Regulator Manual 1R-116.pdf delco_remy_regulator_service 1R-111.pdf

[953 nut 69,104]

Check this video out, better than most.

https://www.youtube.com/watch?v=W8C26XOFAhM

 

[adsm08 5,117]

The regulators rarely actually go bad or break, unless they were hooked up wrong, or were exposed to an electrical fault. These are old designs, from the days when things were meant to be worked on. They can be cleaned and adjusted and brought back to life as they wear.

 

If you remove the top cover and hold the unit right-side up with the three posts facing you the set of contacts responsible for charging will be to your right. Cleaning them with some fine sand paper and making sure all the other connections are good an clean, and the wires are in good shape, is likely all that is needed.

 

There is a website where high-quality regulators can be purchased still. Of course I can never remember what it is. @ebinmaine Eric, is it you that always has to remind me of that site?

[ebinmaine 80,597]

6 minutes ago, adsm08 said:

There is a website where high-quality regulators can be purchased still. Of course I can never remember what it is. @ebinmaine Eric, is it you that always has to remind me of that site?

 

 

Ain't me. Mebbe @Achto or @WHX?? knows?

[adsm08 5,117]

47 minutes ago, ebinmaine said:

 

 

Ain't me. Mebbe @Achto or @WHX?? knows?

 

Not me. I can't remember it, and I can't remember who normally, and I am still dealing with some after-effects of that head shot I took last Friday.

[Achto 32,620]

Give this regulator a try.

https://www.amazon.com/Parts-Player-12V-Regulator-1959-1966/dp/B07Z9LQJDG/ref=sr_1_25

[Handy Don 17,455]

19 hours ago, FLtractor said:

Didn’t not attempt diagnosing regulator.

If you decide to replace, please don’t discard the original--someone here would likely take it to attempt a refurb. 

[squonk 48,056]

Things would work better with the rust cleaned off the connections! 

[adsm08 5,117]

4 minutes ago, squonk said:

Things would work better with the rust cleaned off the connections! 

 

You are right, but if you look at the OP's full body of work on the forum you will notice a pattern that points towards three things.

 

1) He likely does have ADHD.

2) He likely does NOT have any Ritalin.

3) He would rather load up the parts cannon than slow down and diagnose something.

Edited September 26 by adsm08

[WHX?? 58,048]

On 9/24/2026 at 7:17 PM, ebinmaine said:

 

 

Ain't me. Mebbe @Achto or @WHX?? knows?

 

Around here the farm & barn & man malls sometimes have them but watch for the 6 volt offerings. I had bought one in the jungle Dan had posted but still didn't get it to charge right. May have had other issues tho and never did get to the bottom of it. 

 

6 minutes ago, squonk said:

Things would work better with the rust cleaned off the connections! 

 

[adsm08 5,117]

On 9/25/2026 at 11:01 AM, Handy Don said:

If you decide to replace, please don’t discard the original--someone here would likely take it to attempt a refurb. 

 

Yeah, me. I have three on my work bench that I damaged making bad connections that I have since repaired.

 

Depending on what breaks I'm getting pretty good at it. About all I can't do is re-wind the magnet coils at this point.

[FLtractor 219]

11 hours ago, adsm08 said:

 

You are right, but if you look at the OP's full body of work on the forum you will notice a pattern that points towards three things.

 

1) He likely does have ADHD.

2) He likely does NOT have any Ritalin.

3) He would rather load up the parts cannon than slow down and diagnose something.

1) possibly but undiagnosed 

2. correct 

3. would much rather slow down and diagnose but not very mechanically inclined and attempting to learn as I go.. reason I bought the 856 when early 2000s John Deere died after 20 plus years . 
still not entirely comfortable using my cheap harbor freight 7 function muti meter.. need to find better video showing use on tractor or automotive in detail.. did receive some helpful advice on here thank you fellow Wheelhorsian… still need to print out the S/G manuals on here to better learn about that and voltage regulator.. I did read briefly that for voltage regulator should NOT use emory cloth or sandpaper for cleaning connections.. take it that’s INSIDE? But sandpaper ok for all the outside connections terminals for S/G voltage regulator? Will need to open up voltage regulator and clean off the terminal inside that was told on here also helpful Wheelhorsian said usually is reason they not charging. 

Edited September 26 by FLtractor

[adsm08 5,117]

1 minute ago, FLtractor said:

would much rather slow down and diagnose

 

Then slow down, and ask for test steps instead of leads on replacement parts or instructions to remove/bypass nonfunctional systems.

 

I will say, to some degree we, as a group, are doing you a disservice in this area as you often get batches of responses offering conflicting advice, or many seemingly unrelated tests for a single issue. This can be quite confusing to someone who is trying to learn.

 

@squonkhas a very good point in that most of the pictures you post show electrical connection points that are in rough shape. Things like paint and corrosion are not particularly conductive. You would be well served go go through one by one and clean all the electrical connections on this tractor.

3 minutes ago, FLtractor said:

1) possibly but undiagnosed

 

Takes one to know one. I am one, I live with three more, and I'm telling you, your post activity has all the hallmarks.

[FLtractor 219]

2 minutes ago, adsm08 said:

 

Then slow down, and ask for test steps instead of leads on replacement parts or instructions to remove/bypass nonfunctional systems.

Mainly asking about replacement parts is an attempt to learn the cost, availability of similar reliable piece- perhaps not very good way to learn that, so should probably stop asking. 

I will say, to some degree we, as a group, are doing you a disservice in this area as you often get batches of responses offering conflicting advice, or many seemingly unrelated tests for a single issue. This can be quite confusing to someone who is trying to learn.

Haven’t seen much confliction form what I’ve read. 

@squonkhas a very good point in that most of the pictures you post show electrical connection points that are in rough shape. Things like paint and corrosion are not particularly conductive. You would be well served go go through one by one and clean all the electrical connections on this tractor.

Yes I need to do so. 

Takes one to know one. I am one, I live with three more, and I'm telling you, your post activity has all the hallmarks.

Good point. could see that. Get very excited about being so close to having 856 run drive again to be put to work. 

 

[squonk 48,056]

 

[FLtractor 219]

On 9/24/2026 at 8:10 PM, adsm08 said:

The regulators rarely actually go bad or break, unless they were hooked up wrong, or were exposed to an electrical fault. These are old designs, from the days when things were meant to be worked on. They can be cleaned and adjusted and brought back to life as they wear.

 

If you remove the top cover and hold the unit right-side up with the three posts facing you the set of contacts responsible for charging will be to your right. Cleaning them with some fine sand paper and making sure all the other connections are good an clean, and the wires are in good shape, is likely all that is needed.

 

There is a website where high-quality regulators can be purchased still. Of course I can never remember what it is. @ebinmaine Eric, is it you that always has to remind me of that site?

Evening, message some of these questions to Squonk on someone else’s S/G thread as it also related to here.. Did some closer looking at S/G and voltage regulator today … numbered picture.. (yes I know to sand the connections- will do so) # 1 is to farthest right terminal on voltage regulator.. but is outgoing to S/G? 
#2… just looked closer and saw this is offically terminal A…. This  is power TO the S/G from ignition switch from battery. 
#3.. no # just circled .. is this supposed to be as pictured or is mine broken off? 
Also the underneath pic my tab from terminal # 2 wire appears bent and wire frayed in needing replacing. 
You mentioned opening the regulator and sanding the far right connection .. but not exactly sure where to sand here .. also does anything else inside appear too corroded or out of place?
Since told the charging portion of the S/G will crank tractor over … the only terminal on the S/G that would affect it having poor connection is terminal 2 A? as in no external wiring except the 4 AW gauge from ignition to  S/G 2 A makes any difference?
So if that’s clean then it’s my wiring that is the issue since charger works and will have cleaned terminals connections.
Please let me know if post confusing and needs clarifying or better pictures.

Edited 5 hours ago by FLtractor

[pfrederi 21,145]

If you clean up the Genny you will see an F stamped in it like the A you can see.  The right most terminal on the regulator goes to it.. The wire coming from under the regulator goes to the A terminal.

 

The center terminal in the regulator should go to Battery+

[FLtractor 219]

1 hour ago, pfrederi said:

If you clean up the Genny you will see an F stamped in it like the A you can see.  The right most terminal on the regulator goes to it.. The wire coming from under the regulator goes to the A terminal.

 

The center terminal in the regulator should go to Battery+

Terminal F where the wire goes to outside front voltage regulator terminal.. what does that power or do? If starter generator Power goes from battery to terminal A to power the S/G. 
Adsm08 mentioned above how I remove top cover and sand for better connection to see if that fixes the non charging voltage regulator … is anything in the front picture of the voltage regulator with the cover off? - posted his reply for better understanding 

[adsm08 5,117]

2 hours ago, FLtractor said:

 

Evening, message some of these questions to Squonk on someone else’s S/G thread as it also related to here.. Did some closer looking at S/G and voltage regulator today … numbered picture.. (yes I know to sand the connections- will do so) # 1 is to farthest right terminal on voltage regulator.. but is outgoing to S/G? 

Yes. The S/G is the starter and the generator, and as such it needs regulated, which is what the voltage regulator does.

Electrically speaking the only difference between a motor and a generator is the direction the power is flowing.

Quote

#2… just looked closer and saw this is offically terminal A…. This  is power TO the S/G from ignition switch from battery. 
#3.. no # just circled .. is this supposed to be as pictured or is mine broken off? 

 

Inside the unnumbered circle I believe is OK.  None of mine have anything there. These units do naturally produce heat during operation, that may be a vent of some sort. Anything that goes through heat cycles needs to be vented or it will be put through a cycle of pressure and vacuum that will eventually cause the case to fail.

 

Next to the 2 is broken. That ring should be bolted down there, but the stud is broken. It is causing at least 90% of your issues. This is the A terminal, it is the connection the regulator uses to control the magnetic field to move the armature, which in turn cranks the engine. This is electro-mechanically the oppsite is what is happening once the engine is running and it is charging. DO NOT REMOVE THAT NUT. The other side, inside the case, is a bolt with a large wire soldered to it. If you undo that nut without holding the bolt from the inside, best case you drop the bolt, worse case you break the wire. Neither outcome is desirable.
Also the underneath pic my tab from terminal # 2 wire appears bent and wire frayed in needing replacing. 

 

That picture is pretty backlit and hard to see. With small, cheap and easy to make wires like this, when in doubt replace it.
You mentioned opening the regulator and sanding the far right connection .. but not exactly sure where to sand here ..

 

Response will be with last picture.

 

also does anything else inside appear too corroded or out of place?

 

Hard to tell from a picture.

Since told the charging portion of the S/G will crank tractor over … the only terminal on the S/G that would affect it having poor connection is terminal 2 A? as in no external wiring except the 4 AW gauge from ignition to  S/G 2 A makes any difference?

 

A terminal cranks, F terminal charges, if I recall correctly. As pictured the most likely outcome is it charges but does not crank.

So if that’s clean then it’s my wiring that is the issue since charger works and will have cleaned terminals connections.
Please let me know if post confusing and needs clarifying or better pictures.

 

You have a very nice, original, adjustable regulator here. I would do everything I could to repair this piece and keep it rather than replace it. A modern production one will not be as nice, and if it even gets close it will be expensive.

 

The point that I was referencing is on the right in this picture. Push down gently on the top of the tower with the two screws facing the camera. The spot the two piece make contact is the point to clean.

 

The tower on the left has a similar contact point which is more easily visible in the picture. It is on the bottom of the rust-colored tab, straight up from where the black wire is soldered.

 

 

The point in question on the right side SHOULD be directly under the circle in the middle of the RH tower in this picture.

 

 

 

 

Finally, that center connection is atrocious. I would look at replacing that wire end with a proper ring terminal. That will delete the square washers. I will post links to some good wire-working tools and supplies down in the main body of my response.

 

 

There is certainly a lot to unpack here. I am going to put my responses in red inside the quote to try and keep them as close to the question they are answering.

 

Wire stripper: https://www.amazon.com/dp/B00IXAK7DE?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

 

I like this wire stripper for a few reasons. It is easy to use, works well in tight spots, has an integrated cutter (and supposedly a crimper, but  I've never figured the crimper out), and is easier on the wrists and fingers than a lot of the plier-style strippers. The biggest draw-back is that it does not work well on wires smaller than 18 gauge. There should not be any wires that small on your tractor.

 

 

Wire crimper: https://www.amazon.com/LEONTOOL-Wire-Stripper-Compact-Non-Insulated/dp/B0CHMLCJW4/ref=sr_1_19?crid=K3XCF0X3F9SF&dib=eyJ2IjoiMSJ9.3s25cFWOlDGBp_Cc5bsnhhDPDzKYZ924SOqEVx08ZnFDVkAp9c7HvqoHDJsMXAnr_PCWaisu1lOad_im2Rpn8xhZzjbR3pIGKEBhJI9LQJuHUdtDlFKByYQWtrx_ykStwtfg7iu655gMzA0q_uLyNwey3EjnE8ghoBOpid1Z3z8YoQvX00OfdVgendFnb0Qb05j6MkTeaQ1E9uIUbLj-id8oELquch1M_X3ruJt3M07llwvZSd8S2BFTJepgpFy-ONM7ACpam2OCtpJ_50UUW7pLmJXpVGlK7_deVAQZGXw._UpyhpH44IX99zRBAcLB7z0L_nQhdnam6cegCUQ4yCk&dib_tag=se&keywords=wire%2Bcrimping%2Btool&qid=1790982426&s=hi&sprefix=wire%2Bcrimp%2Ctools%2C150&sr=1-19&th=1

 

I have not used this exact one personally, but this style wire crimper is good. The stake near the tip should be used on every crimp. A non-staked crimp can come undone much easier than a staked one.

 

Ring terminals:https://www.amazon.com/600Pcs-Heat-Shrink-Connectors-Electrical/dp/B0CYM4Q816/ref=sr_1_1_sspa?crid=1DD3XJIIYSE96&dib=eyJ2IjoiMSJ9.eHygAPEFMm4zJSUjb2VRW5sSHnfpK6r6HiFMx0eQc5gcJARSY35MhOdhDqN3VmVrZYE9Mkcl9O5B8zI_-smlpUZshuoKZGeiwB70bydmV6R2_J-EtvS1N8GMK7V5aCH6BNreWyMUueDxDtCZQswbl84vHv77V9B5DdKgdtCbPkXDQniL8RWvUzLaNxZ83ejYtpWCsCVeUK5Xl92DxN4_9Nz49Buixr5IURn9oRYweiaR7q5-Uu2vQl4R2LuqlL7NSEj9Uc6pvzCQckCJ3cr5vx0xjQ71oIKBwEs02aGR-A8.xmMMyzIZYjBVr3iZ3UINWGTxYj3eocn0HPHLoSumUTI&dib_tag=se&keywords=wire%2Bring%2Bconnector%2Bassortment&qid=1790982563&s=hi&sprefix=wire%2Bring%2Bconnector%2Bassortment%2Ctools%2C121&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

This is not the highest quality set, but should be good. It has heat-shrink tubing pre-installed. Heat shrink is a MUST for any wire repair. After the connection is crimped you heat the tubing and it shrinks down and seals out moisture and provides electrical insulation at the connection, both are important.

 

Heat shrink tubing: https://www.napaonline.com/en/p/NW_729137

 

This is needed for proper sealing of repairs made mid-wire. Always buy adhesive laden tubing. It has something like hot glue in it that will flow out and seal once it is properly heated.

 

The pieces in that kit are 5 to 6 inches long, and can be cut to length. Typically, for a well done repair, a piece 1.5 inches long is sufficient.

 

Heat gun: https://www.harborfreight.com/1500-watt-11-amp-dual-temperature-heat-gun-56434.html

 

This, not a lighter, is the proper tool for shrinking heat shrink. The link is to the exact one I own.

 

Butt crimps: https://www.amazon.com/SVAAR-200PCS-Tinned-Copper-22-6/dp/B08R2N8F46/ref=sxin_12_pa_sp_search_thematic_sspa?content-id=amzn1.sym.c50e4cd8-fa0e-4c88-b77e-b1f9601d89fd%3Aamzn1.sym.c50e4cd8-fa0e-4c88-b77e-b1f9601d89fd&crid=3LK4A8SF8VHHS&cv_ct_cx=butt%2Bcrimp%2Bconnectors&keywords=butt%2Bcrimp%2Bconnectors&pd_rd_i=B08R2N8F46&pd_rd_r=1bab920f-2322-4f7d-9136-d6303b094c8e&pd_rd_w=q0SMl&pd_rd_wg=fF1sb&pf_rd_p=c50e4cd8-fa0e-4c88-b77e-b1f9601d89fd&pf_rd_r=BHX8K4G9ZSGD0T7KG5GK&qid=1790983028&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sprefix=butt%2Bcrimp%2Caps%2C156&sr=1-4-e169343e-09af-4d41-85b1-8335fe8f32d0-spons&aref=j0Mj2lguoq&sp_csd=d2lkZ2V0TmFtZT1zcF9zZWFyY2hfdGhlbWF0aWM&th=1

 

These are for connecting wires to each other, if you can't solder for some reason. The connection can also be soldered once crimped if desired. These with the heat shrink I linked to are my preferred vs buying the crimps with the insulation already installed, as crimping can damage that insulation. This way you crimp, then install the insulation afterwards, no damage. If your smallest crimp is still too big for the wire you are working on you can strip extra insulation and fold it over to make that section thicker so it fits better. This is a situation where soldering over the crimp is a really good idea.

 

Edited 3 hours ago by adsm08
added info on heat shrink

[adsm08 5,117]

21 minutes ago, FLtractor said:

 

This picture makes the A terminal on the S/G unit look much less broken than the other picture. That ring terminal still needs to be bolted down to it.

Edited 3 hours ago by adsm08