94/95 312 wiring to k321 what am I missing?

[MainelyWheelhorse 1,343]

Todays fun project is trying to wire a 94-95 312 wiring harness to a k321. I’ve been looking at the wiring schematic for the tractor and I think I’ve got most of it. I took out the oil sentry and safety switches as the C141 is late 70’s. I did notice after looking at the schematic, I have no start wire. I’ll put that on once I go back in the workshop. I’ve got one white wire at the moment to go over to the K321.

I’d assume I need a start wire and ground wire and I’ll be all set right?

The dash is wired to the solenoid and from the schematic or as close as I could get.
The K321 just has a positive, negative and ground wire right? Anyway here’s what I have so far. Thanks!

 

 

 

[pfrederi 18,550]

The 94-5 312 harness was designed for a magneto (Magnum)  Engine your K 321 is going want a powered ignition

[953 nut 59,185]

What number ignition switch are you using?    Should be a 103 990.  Your Kohler K series engine will need three wires to the engine, one that has power with the key ON or in START and two wires from the stator to the voltage regulator AC terminals. Use this as a guide.

[MainelyWheelhorse 1,343]

Thanks, @pfrederi and @953 nut I downloaded the schematic for the C141 as well to check for differences. This has been a bit of a learning curve but in a good way.

[gwest_ca-(File Mod) 11,388]

Does the center black wire on the regulator go to ground? Should it not be the B+ terminal that charges the battery?

The 2 white wires should go on the center B+ terminal I think.

Where did the green wire come from?

[pfrederi 18,550]

I think the 2 white wires are AC from the stator and should be separated and go to the AC terminals on the regulator... center terminal goes to battery..  On that note this regulator is for a magnum engine and should be mounted in the air shroud....Or at least some place with good ventilation

[953 nut 59,185]

Do you have the safety switches for the C-141 on the tractor and are you going to connect them to your wiring? The safety switches for the 312 are connected differently.

Will you be using an Amp Meter or a Volt Meter? What is the number on your ignition switch?

We can help you with this but much of the 312 wiring is incompatible with a battery ignition engine.

.

[MainelyWheelhorse 1,343]

@953 nut there was nothing I noticed except the headlight wires. The C- 141 had nothing for safety switches I could find. I figured the 312 wiring could be a good jumping off point. Neither the only thing I have in it now is the hour meter for the K321. Should I add another gauge? The only number I see on the switches is the patent number unless I’m wrong. It also says ABC on the plug side. In my opinion looks the most like the Toro 103990 at least plug wise. There are no numbers or letters on the pins. I had it so I figured I’d use it. I have another that also has 6 plugs like of the one in the photo but one is on the left side. @ebinmaine and I have been texting back and forth and he advised me that a Toro 103990 could work. I took out the 312 safety switches which cut my wire count by a third and simplified it.

 

@gwest_ca I was following a 95 312 wiring schematic when I set this up. I have since unhooked all of it and I’m going off of the schematic  @953 nut posted. 
 

@pfrederi in that picture there is nothing from the engine side hooked up yet. I was going off a 95 312 wiring schematic. I have since started over and I’m using the one that @953 nut posted. That was until I was advised that the key switch may be wrong for my setup. I figured that the rectifier there does the same thing as the block that was originally there. And it’s a lot less bulky. The hood is open on both sides and slotted in the front it should have adequate ventilation.

 

Thanks for the guidance and help. If I need to completely rewire it than so be it. I like a challenge.

 

 

 

the key switch with the offset pin and what I could find on that pin the first key switch had nothing.

 

 

my original Keyswitch I have cleaned up both since the pictures.

 

 

what I’d like to run for instrumentation etc…

 

[953 nut 59,185]

7 hours ago, MainelyWheelhorse said:

@953 nut there was nothing I noticed except the headlight wires. The C- 141 had nothing for safety switches I could find. I figured the 312 wiring could be a good jumping off point.

The safety switch wiring is quite different on a magneto wired unit than that on a battery ignition unit. On battery ignition you use safety switches to interrupt the 12 volt supply going to the ignition coil. On the magneto wiring you use safety switches to ground out the magneto.

Neither the only thing I have in it now is the hour meter for the K321. Should I add another gauge?

You don't NEED aa volt meter or amp meter but if you wanted either we can show you how they are wired.

The only number I see on the switches is the patent number unless I’m wrong. It also says ABC on the plug side. In my opinion looks the most like the Toro 103990 at least plug wise. There are no numbers or letters on the pins. I had it so I figured I’d use it. I have another that also has 6 plugs like of the one in the photo but one is on the left side. @ebinmaine and I have been texting back and forth and he advised me that a Toro 103990 could work. I took out the 312 safety switches which cut my wire count by a third and simplified it.

The 103990 switch should have some markings on or near the terminals where the wires attach. Many other ignition switches look very similar but the switching is not the same. The thread below will give you a better idea of the differences.

@gwest_ca I was following a 95 312 wiring schematic when I set this up. I have since unhooked all of it and I’m going off of the schematic  @953 nut posted. 
 

@pfrederi in that picture there is nothing from the engine side hooked up yet. I was going off a 95 312 wiring schematic. I have since started over and I’m using the one that @953 nut posted. That was until I was advised that the key switch may be wrong for my setup.

Take a look at the post attached below, you should be able to use the ohm meter to determine what switch you have. If any of the terminals have "M" on them it is not for a battery ignition system. I use the 103990 switch because it is a common switch that is readily available and lower cost than many others. Other battery ignition switches can be used but we will need to know what the order of the terminals is.

I figured that the rectifier there does the same thing as the block that was originally there. And it’s a lot less bulky. The hood is open on both sides and slotted in the front it should have adequate ventilation.

The rectifier you have will probably work, when you mount it you should have a spacer below it so the maximum amount of surface area is exposed to airflow to keep it from overheating.

 

[gwest_ca-(File Mod) 11,388]

This is the switch used on the 1994-95 312 models

 

[MainelyWheelhorse 1,343]

@953 nut I bought the Genuine Toro 103990 switch last night. Hopefully that straightens out the wiring issues. Thanks for the help, I think my title fits more now since beginning this project.😁 

[clueless 3,181]

Please DO NOT try to use the K341 with the 312 wiring harness and the switch and vice-versa until you understand what the folks here are show you. Assuming one works with the other, well you know what the say about assuming, is not good. If you don't do it correct, you could screwup the the K and the wiring harness on the 312 then you've got two problems. 

[pfrederi 18,550]

The switch shown above will not operate a K341.  It will not power the ignition.

[MainelyWheelhorse 1,343]

2 hours ago, pfrederi said:

The switch shown above will not operate a K341.  It will not power the ignition.

 

2 hours ago, clueless said:

Please DO NOT try to use the K341 with the 312 wiring harness and the switch and vice-versa until you understand what the folks here are show you. Assuming one works with the other, well you know what the say about assuming, is not good. If you don't do it correct, you could screwup the the K and the wiring harness on the 312 then you've got two problems. 

I was advised to get a Toro 103990 switch to operate the K 321/41. I bought it last night. That part should be fine once it comes in unless there are other issues. Thanks for letting me know though.

Edited May 30 by MainelyWheelhorse

[pfrederi 18,550]

When you get the switch check the terminals. You need an "I" terminal. (No "M" terminal)  Double check... look for continuity between The "B" terminal and the "I" terminal when you turn the key switch to Start.

[953 nut 59,185]

8 hours ago, MainelyWheelhorse said:

@953 nut I bought the Genuine Toro 103990 switch last night. Hopefully that straightens out the wiring issues. Thanks for the help, I think my title fits more now since beginning this project.😁 

That is a good first step. Look at the wiring to the switch @gwest_ca posted. That should be how the ignition switch socket on the 312 switch is presently. That wiring arrangement is NOT what you need for the 103 990 switch but the wires can be relocated to make a working ignition, charging and starter circuit and get you out of the shop and onto the lawn with the C.

You should remove all of the wires from your five terminal block (see YouTube video below) except the "Start"  wire. Now insert the wires in the order on the left diagram. Using the diagram I furnished earlier the wirer to the center terminal of your rectifier will go to the "R" terminal of the block, the accessory wire for lights and hour meter will go to the "A" terminal, the red wire coming from the battery via the solenoid will go to the "B" terminal.

 

[MainelyWheelhorse 1,343]

@953 nut I’ve also been talking to @ebinmaine on the wiring issue he advised me to get the 103990. Thanks for the help. This has definitely been a learning experience.

[MainelyWheelhorse 1,343]

Alright, so I’ve got the correct key switch wired by 953nuts schematic. the K321 has a 3 pin plug to harness, I have both the male/female plugs from the 312, which are 5 pin where do the 3 pins for the K321 go in the 5 pin plug. I’d assume it’s the very bottom slot and the two on the left and right above it, Correct? Thanks!

 

 

Edited June 5 by MainelyWheelhorse

[953 nut 59,185]

12 hours ago, MainelyWheelhorse said:

the K321 has a 3 pin plug to harness, I have both the male/female plugs from the 312, which are 5 pin where do the 3 pins for the K321 go in the 5 pin plug.

The five pin from the 312 had two blue wires going to the low oil switch, you don't have a low oil switch so those aren't needed. The white (or pink) wire to the five terminal plug was the B+ terminal wire from the engine mounted voltage regulator but your VR is remotely located so you don't need that wire. The other wire going to the five terminal connector (there are only four wires going to it) went to the magneto on the Magnum engine but you have a battery ignition so you don't need that wire either. In short, you don't need anything from the five pin connector.

I am not sure what the K321 was connected to so you will need to trace them out. Two of them are probably the wires from the stator that bring AC to the voltage regulator and disappear behind the flywheel cover, they will go to the outer terminals of the voltage regulator. The third wire probably goes to the ignition coil + terminal and will connect to the ignition switch "I" terminal.

Hope this helps.

[MainelyWheelhorse 1,343]

1 hour ago, 953 nut said:

The five pin from the 312 had two blue wires going to the low oil switch, you don't have a low oil switch so those aren't needed. The white (or pink) wire to the five terminal plug was the B+ terminal wire from the engine mounted voltage regulator but your VR is remotely located so you don't need that wire. The other wire going to the five terminal connector (there are only four wires going to it) went to the magneto on the Magnum engine but you have a battery ignition so you don't need that wire either. In short, you don't need anything from the five pin connector.

I am not sure what the K321 was connected to so you will need to trace them out. Two of them are probably the wires from the stator that bring AC to the voltage regulator and disappear behind the flywheel cover, they will go to the outer terminals of the voltage regulator. The third wire probably goes to the ignition coil + terminal and will connect to the ignition switch "I" terminal.

Hope this helps.

Thanks, that definitely helps. What I’m trying to do is take the shell of the male 5 pin plug and put it in place of the 3 on the K321. as I have both male and female plugs. I only have the male 3 pin plug on the K321 so since I had both male and female sides of the 5 pin I figured I’d swap them over.  Do I just copy the 3 pin layout on the 5 pin? Then do the same for the harness plug? Thanks! 

[953 nut 59,185]

It doesn't matter what pattern you use since it is your own layout and they match up.

I presume you already know how to use the Packard 56 terminals but if not this video can be helpful.

 

[MainelyWheelhorse 1,343]

@953 nut Ok, so basically as long as they match up it doesn’t matter the order. Right? That definitely simplifies it. Thanks!