Wiring puzzle in 1980 C1100

[graywolf1939 29]

I have several wires on my WH 1980 C1100 that have me wondering where they go after an engine overhaul. I have included photos. The engine is an original Briggs 11HP. It uses a Magneto system (no points and coil).

I don't know where the white wire goes that is coming up behind the fly wheel behind the magneto. Then there are two (2) red wires exiting beneath the flywheel and go to what I think is the diode rectifier, the second red wire I believe is not used on the other side of the rectifier because my model was not purchased with headlights which would have used AC from the rectifier. Then there is the Black wire which is on the magneto via a push ON female connector and this runs to a ground screw on the front of the tractor; see 2nd photo.

[gwest_ca-(File Mod) 11,664]

Do you have the B&S service manual?

Some B&S wiring info

 

[graywolf1939 29]

I don't have the B&S manual, but my WH Owner's manual under section 9 - Engines lists the engine B&S number as 252417  Type 0198-01 

[953 nut 61,631]

This B&S Service Manual is listed for your model. Also this electrical service manual is listed for your model. The black wire (or any other wire) with a crimped end on it is NOT factory wiring and should be considered suspect.

 

[graywolf1939 29]

Thank you for your reply, as a vet also, thank you! I am still having a problem trying to find my exact wiring diagram. All the ones I see for the 1980 C series show a coil and points, I have a magneto, no coil or points.

My WH is a 1980 C1100 Special, I guess they didn't make many of the Special class!!

[gwest_ca-(File Mod) 11,664]

This manual has B&S models

 

[graywolf1939 29]

Thank you for your reply, I really appreciate the help, at age 86+ I am running short on finding answers. Here is my wiring diagram from my owner's manual, working all morning in sweltering heat and still cannot find out what the white wire is for.

 

I cannot understand why this engine ran with the black wire from the magneto connected to ground on the front of the engine, see photo. And I cannot find out what the WHITE wire is used for which comes up from behind the flywheel behind the magneto.

[gwest_ca-(File Mod) 11,664]

Where does the white wire come out?

The engine to tractor connection on the engine side of the connector there may be a diode covered with tape. Squeezing the tape you should feel the diode - 3/16" diameter x 3/8" long. That would be the charge wire for the battery.

The only other thing behind the flywheel is the stator and I don't know what one you have. How does the operator manual describe the charging system? Dual circuit? Tri circuit? Amps?

[gwest_ca-(File Mod) 11,664]

In one of your earlier photos the yellow tractor wire goes to the engine stator for AC power for lights.

The orange tractor wire should have the diode in it on the engine side of the plug together connector. Diode would be under the insulating sleeve.

 

See a black wire going to where the throttle cable is connected. That is usually a ground connection made when the throttle cable is pulled back to idle. The carb throttle linkage makes the connection.

The black wire with the blue insulated eyelet is not original. Does it connect to the above black wire?

[gwest_ca-(File Mod) 11,664]

Wonder if someone had a problem with the kill relay and replaced the ignition switch to one for magneto ignition?

This model uses a battery ignition switch to control the kill relay that controls the magneto ignition.

This is the original ignition switch. Click on the picture in the link and again on the thumbnails that come up.

 

[graywolf1939 29]

The white wire had been damaged years ago and black wire was added on and ring connector. The white wire can be seen exiting at top of stator in one of my photos. There are two red wires exiting the bottom of the engine and those two wires go to diode housed in a plastic casing that you can see in one of the photos. One of the red wires becomes a yellow wire after the diode and is not used because it was there to provide AC for lights which my tractor did not have. I also have a kill switch solanode.

[gwest_ca-(File Mod) 11,664]

If it runs fire it up and see if you have AC voltage at the black wire with blue insulated terminal.

The 1979 C-111 8-speed model 91-11B801 used the same engine and spec.

There is a 1979 C-111 Automatic model 91-11BS01 listed but no evidence it was ever made.

[graywolf1939 29]

I will fire it up as soon  as I get it back together, good suggestion, thank you mon ami.

[gwest_ca-(File Mod) 11,664]

Added some color to the wiring

 

[graywolf1939 29]

You nailed it, this is the exact model and wiring diagram right to the exact color of wires.  The only thing I still do not know is where the white wire is going to. I think you are correct in earlier comment, it comes from the stator and connects to the engine just under the carburetor linkage somewhere and acts as a shut off when the throttle lever is moved to OFF position, I just don't know where as it has broken off years ago I assume.

[gwest_ca-(File Mod) 11,664]

Here is the engine operator manual. There is a section on the remote throttle. It shows the stop switch and it may just be a spring clip to grab a bare wire. When the throttle goes to idle you may see it move. It may hold the wire on the back side of that control panel.

Do not allow any battery voltage into the mystery wire. If it is a kill wire for the coil, voltage will burn it up in an instant.

 

[graywolf1939 29]

The white wire has to be a stop/via grounding wire at the carburetor because the wire was/is too short to reach anywhere else. I will prove this out when I  get the engine running and then stop the engine by touching the white wire to gnd.

 

A big thank you for your help and patience. 

[graywolf1939 29]

I am still working on some puzzling wiring issues with my 1980 C1100 SPECIAL model. In comparing 1982 models using the same 11HP B&S engine my 1980 has both wires from the seat switch wired back to each side of the PTO switch while the 1983 models and some others in that era have one wire at the seat switch grounded AT the switch, while the other wire from the seat switch runs back singly to the PTO switch. On my model I don't understand the purpose of both wires run back to the PTO switch because my wiring diagram shows that each contact on the PTO on the same side is both normally shorted when the PTO is in DISENGAGE position. So, when the seat switch is engaged, operator seated, those two wires are shorted together at the seat, so why short them also at the PTO when in the disengage position???

[953 nut 61,631]

The "KILL RELAY" system used on Specials was a means of controlling the ignition system of a magneto engine while using a battery ignition wiring harness.

10 hours ago, graywolf1939 said:

I am still working on some puzzling wiring issues with my 1980 C1100 SPECIAL model. In comparing 1982 models using the same 11HP B&S engine my 1980 has both wires from the seat switch wired back to each side of the PTO switch while the 1983 models and some others in that era have one wire at the seat switch grounded AT the switch, while the other wire from the seat switch runs back singly to the PTO switch. On my model I don't understand the purpose of both wires run back to the PTO switch because my wiring diagram shows that each contact on the PTO on the same side is both normally shorted when the PTO is in DISENGAGE position. So, when the seat switch is engaged, operator seated, those two wires are shorted together at the seat, so why short them also at the PTO when in the disengage position???

The safety switches are powered to hold the kill relay contacts OPEN from the "I" terminal of the ignition switch. Without power to the relay it will close grounding the magneto. On the later models the wiring harness was changed and the kill relay was no longer used.

The PTO switch opens when the PTO is ON but the seat switch is in parallel with that pair of contacts. On your model IF the operator is in the seat with the PTO ON the power to the Kill Relay will be maintained because the seat switch will CLOSE to keep power flowing to the relay.

Hope this explanation is helpful.

 

[graywolf1939 29]

Ahh, that makes sense, the company had wire harnesses extra in inventory as the Specials were being built, so this is a way to use the inventory, just design them for use in kill circuitry, why not.

 

I am doing some TS this morning to check out the kill relay, I suspect it is bad because if the magneto wire is connected to B on the relay, the engine will not start unless I pull that wire off the relay. After 45 years the tiny little relay arm must be tired out and is stuck on the ground contact, or the coil itself is broken. I have a new 5 contact replacement relay ordered to be prepared.

[953 nut 61,631]

You can pick up an automotive 5 pin relay and socket at any auto parts store for less than $ 10.00. Even Walmart has them available for shipping.  https://www.walmart.com/ip/2-Pcs-Relay-Harness-5-Pin-5-Wire-80A-12V-Jd2912-1Z-12Vdc-Spdt-Socket-Plug-14Vdc/15626767431?wmlspartner=wlpa&selectedSellerId=101294820&selectedOfferId=567C13C0CDE0304291AB5B31213A3048&conditionGroupCode=1&wmlspartner=wlpa&cn=FY25-ENTP-PMAX_cnv_dps_dsn_dis_ad_entp_e_n&gclsrc=aw.ds&adid=22222222297567C13C0CDE0304291AB5B31213A3048_0000000000_21407473164&wl0=&wl1=x&wl2=c&wl3=&wl4=&wl5=1026125&wl6=&wl7=&wl8=&wl9=pla&wl10=736876983&wl11=online&wl12=567C13C0CDE0304291AB5B31213A3048&veh=sem&gad_source=1&gad_campaignid=21690411341&gbraid=0AAAAADmfBIrx-4ZCbXsUFuN9-TN1OuVai&gclid=CjwKCAjwk7DFBhBAEiwAeYbJscTnEXWRAktYgqPENNerZqqlWbQS8sAuIRs52CjMXZ_vHRL0KLezeRoC7gMQAvD_BwE

I did this post a few years ago when they were only $ 5.00.

 

[graywolf1939 29]

The black wire on the magneto, a push-on connector reads ground, and I have it disconnected from the insulated mounted push-on connector on the bracket beneath the carburetor. The wire is OK, the insulated mount is OK, not shorted to gnd. Yet the tractor starts with this black wire connected. My question is, should the black wire on the magneto read ground when disconnected at the opposite end and just connected to the magneto push-on connection?????? I am reading ground from the disconnect end? How can the engine start if the magneto connection is grounded????

[gwest_ca-(File Mod) 11,664]

My guess is your meter is not showing the very low resistance in the primary coil windings. Try connecting to the wire at the coil and see if resistance changes as you ground and unground the wire to the engine.

Try the same thing with the spark plug wire. All this with the engine not running.

The resistance of the primary winding + the resistance of the secondary winding will equal the resistance between the ignition wire and spark plug wire. Reason being the wire in both windings start out connected together.

[graywolf1939 29]

I removed the kill wire from the magneto (primary winding) started the engine just fine, then I took a long blade screwdriver and shorted the primary connector tab to ground, and the engine stopped as it should. I am highly suspicious of the kill wire coming from the magneto to the insulated terminal nearby at the bracket under the Carburetor, it has a few cuts in the jacket and has been spliced once with tape. It reads short from end to end, but I am going to replace it. I noticed that the kill wire from kill relay was not connected to the same insulated terminal on the same bracket as the black wire from the magneto, therefore it explains WHY the tractor would start and also why it would not shut off. So I have a kill relay that is probably bad as well as the black wire that may have breaks in many of the strands yet will read short but not giving a solid ground at the magneto.