# Engine w/ voltage regulator replaced with one without reg



## Kevin Bedard (May 10, 2018)

Hi. I have a Craftsman 917.271100. The original Kohler CV16S blew up. I'm trying to replace it with an older Kohler engine but the model # sticker has been torn off. The biggest difference is the CV16S had a voltage regulator, thus 2 AC output wires coming from the stator, and the replacement engine has only 1 AC output wire (and a single DC output wire). I've poured over the schematics and done checks with my voltmeter and I cannot figure out where to connect the single-wire AC output from the stator of the older replacement engine in the wiring harness. There were 2 yellow wires coming off the regulator that go to a relay, but if I'm reading it right, the relay separates them when the engine is running (open circuit), and connects them when not. Seems pretty pointless to even have the relay there, but I must be missing something. No other wires besides the 2 yellows, and power and ground, connect to the relay. Any ideas?? Is it even necessary? All the AC output does is run the lights, correct? Can I just chop this relay out completely??


----------



## Kevin Bedard (May 10, 2018)

Schematic shows the AC output should connect to the A terminal of the ignition switch (I think), but this already has 12v DC when the key is in the run or run/lights position. I can't connect an AC source to this same terminal, correct??


----------



## Bill Kapaun (May 8, 2007)

You'll have to cut the jumper between A & L.
DC will go to L.
You'll need to run a wire from the AC output to A.
Attached schematic with the same key switch and "similar enough" schematic w the Dual Output system.
IF you don't need LIGHTS, just tape off the AC wire.
In this configuration, using the lights is going to cause a "couple" Amps discharge, since they draw about 5 Amps. Using the AC gives you the full 3 Amps for battery charging. That's already pretty minimal.

Could you do me a favor.
On another forum, a poster has the same model (271100) but he apparently has 3 Operator Presence Relays and the schematic shows NONE.
Would you look at your seat switch and let me know if it has GREEN or BLACK wires? It should be BLACK if the schematic is correct.
He actually has the tag showing the number, so it would have been a major job to modify it to what he has now. I'm just trying to verify that the schematic is correct in the manual.
Thanks-


----------



## Kevin Bedard (May 10, 2018)

Hi. The schematic in my 271100 owners manual is either not complete or just wrong. I found one that is very, very close, showing all 3 operator presence relays and the proper wire colors. Unfortunately, I have it saved in a file at home, not here at work. I'll post it when I get home.

BTW, both wires to/from the seat switch are green, sorry to say.


----------



## Bill Kapaun (May 8, 2007)

Thanks Kevin. That confirms the problems we are having. That person also has 3 relays.


----------



## Kevin Bedard (May 10, 2018)

I am seriously thinking of cutting out the operator relay #2 because I can't figure out what it does. Its input are the 2 yellow wires from the ac terminals of the regulator. When the relay has power (key on), these 2 wires are separated, and when the relay does not have power (key off), these 2 wires are connected. I don't see the point. Can you explain?


----------



## Bill Kapaun (May 8, 2007)

I have what I believe to be a correct schematic.
971.271130 & 271140 have the IDENTICAL engine model/spec AND 3 relays.
(I have a home made database with over 1000 Craftsman models & over 200 DIFFERENT schematics)

OPR 2 is a stator brake. It basically shorts the 2 stator leads together to help the engine slow down faster when the key is turned off or you leave the seat. 30 & 87A terminals are somewhat known for arcing. I guess terminals get a bit cruddy and then 15A shorting through them does the rest.

OPR 1 is to kill spark if you leave the seat.

OPR 3 disconnects the VR from A1/A2. Seems pointless, since turning the key off disconnects it from the battery.

And back to the original question about wiring the lights- per the schematic I just posted.
You'll want to disconnect/cut A2 from A1. Run the AC output to A2.


----------



## Kevin Bedard (May 10, 2018)

AH! Excellent! The original Kohler CV16S engine had a stator brake but the engine blew. The replacement CV15 does not have a stator brake, so I think I'm safe removing that relay. 

The schematic I'll post this evening has separate drawings for the stator brake and the alternator. But the model number at the top is not 271100.


----------



## Bill Kapaun (May 8, 2007)

I'm pretty confident my schematic is correct. They "tended" to use the same schematic# in model "groups" in the same era, so a 271100, 130 & 140 suffixed ones "kind" of make sense.

Craftsman did the 3 OPR thing for what appears to be a fairly brief time.
They are only on Kohler Command powered tractors. No Briggs etc.
They even put them on the 3A charging system ones. That couldn't have offered a whole lot of braking!
I have a hunch, that after a couple? years they started having problems with all the extra connections and dumped the concept.


----------



## Kevin Bedard (May 10, 2018)

Here's the schematic from a 271041 mower. Even though not a 271100, everything is perfect on this diagram. Notice the stator brake in the lower left, with 2 yellow wires going to OPR2. Notice the 2 green wires to the seat switch. Even the black and brown wires to the headlights are correct. My 271100 is wired EXACTLY like this diagram.


----------



## Bill Kapaun (May 8, 2007)

For Sears, Orange supplies the headlight switch and Brown goes from the switch to the headlights.
Black is just ground and the kill wire circuit.

What's odd in your schematic, is that it appears you have to be in the seat for the headlights to work, since the headlight supply is tapped off the OPR 2 power supply. (which comes from OPR 1 from the seat switch) I've never noticed a schematic like that before.

IF that's how your headlights work, it's probably a good schematic.
IF not, use the one for the 271130 I posted.
Otherwise, they appear to be the same thing, electrically.

Cut the ORANGE wire from that supply point and feed the AC output to the Orange for lights.

With your 3A output, there's not a lot left for battery charging after supplying 3 OPR's and a Fuel Solenoid.


----------



## Kevin Bedard (May 10, 2018)

I have successfully cut out opr2, since the replacement engine has no stator brake, and jumped opr1 to opr3. I also removed the kill wire from the coil and the engine starts right up. For some reason, the kill wire is grounded all the time, no matter where the key is. I'll have to dissect the entire harness to figure this out. I thought maybe the key switch was bad, but now I'm not convinced. It could be a relay or switch not working. Disconnecting opr1 did not solve the issue.


----------



## jhngardner367 (Apr 5, 2011)

How many terminals are on the switch?
If it has 6,it's the wrong switch,as there's an extra ground on them.
Normally,they have :
B/+(battery)
L=load(lights,etc.)
M=armature/magneto
G=ground
S=solenoid


----------

