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Discussion Starter #1
Can someone tell me if the B+ wire on a three wire Kohler Magnum MV20 regulator/rectifier is supposed to remain hot even when the key is turned off?

I changed out the ignition switch and notice I always have full battery on the B+ lead.... I'm wondering if I have the wires on wrong? Thanks
 

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Can someone tell me if the B+ wire on a three wire Kohler Magnum MV20 regulator/rectifier is supposed to remain hot even when the key is turned off?

I changed out the ignition switch and notice I always have full battery on the B+ lead.... I'm wondering if I have the wires on wrong? Thanks
Normally, you should get power on the B+ terminal of the regulator only with the key on.
Maybe it was supposed to connect to the "L" terminal on your switch?
 

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Discussion Starter #3
Normally, you should get power on the B+ terminal of the regulator only with the key on.
Maybe it was supposed to connect to the "L" terminal on your switch?
G-1 I was thinking the same thing.

My snapper manual shows the red wire on L terminal goes to the hour meter, buzzer and clutch switch.

G terminal is what the manual calls a black off wire from the starter.

M terminal is the blue off wire for the magneto.

S terminal has a red wire that comes from the solenoids spade connection

B terminal is a Red fused wire coming from the 10 mm stud on the selonoid.

I have full battery at the B+ lead all the time...:banghead3
 

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Discussion Starter #4 (Edited)
The B+ wire is always hot. It comes directly from the starter solenoid's 10 mm battery stud terminal.

The rectifier/regulator's B+ wire is purple on Kohler's side of the engine harnesses snap connection.....the other side of the snap connection is Snapper's wiring harness where the wire turns red and makes it's way through a 20 amp slow blow fuse back to the starter selenoid's battery stud.

On the switch's G terminal is a blue wire, it's the engines magneto kill.

I have 14.3 volts output on the B+ wire terminal measured right above the plastic harness with harness hooked up.
 

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The B+ wire is always hot. It comes directly from the starter solenoid's 10 mm battery stud terminal.

The rectifier/regulator's B+ wire is purple on Kohler's side of the engine harnesses snap connection.....the other side of the snap connection is Snapper's wiring harness where the wire turns red and makes it's way through a 20 amp slow blow fuse back to the starter selenoid's battery stud.

On the switch's G terminal is a blue wire, it's the engines magneto kill.

I have 14.3 volts output on the B+ wire terminal measured right above the plastic harness with harness hooked up.
Doesn't sound right to me to keep power on the regulator. Just for fun, I pulled the wire off my B+ regulator pin on my Kohler M20 and metered resistance to ground. My meter measured 350 in one direction and 450 in the other direction on the Rx100 scale. The actual numbers don't mean much, but it's clear there would be some drain on the battery if left connected there.

Not sure what's going on with the magneto kill wire. You first said its on the switch "M" which is normal. Then you said it's on the "G"? If "G" is connected to ground, how would the engine ever run?
 

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Discussion Starter #6 (Edited)
G1 on page 22 of the Snapper Safety Instructions & Operators manual there is picture of the switch's back side with the terminals lettered.

At 12 O'clock is terminal B, a 20 amp fused red wire going to the starter solenoid's 10 mm battery terminal.

9 O'clock is terminal S, it is a red wire which goes to a male spade connection on the starter solenoid.

3 O'clock is G terminal, it is a black wire that says off, it shows it going to the starter.

7 O'clock is M terminal, it a blue wire going to the magneto that also says off.

4 O'clock is the L terminal, it says run with a red wire going to the hour meter and to the buzzer.


I traced the blue or purple colored B+wire from the regulator/ rectifier through the kohler side of the harness, it turns red at the Snapper side of the connection and then goes to a 20 amp fuse and then directly to the solenoid's 10 mm battery stud. The Blue magneto wire has to be the kill wire or it wouldn't have to be there.

I don't understand it myself but that's what I have. I'll check the battery tomorrow to see if the voltage has drawn down.

I'm thinking it won't drain the battery unless the diode has shorted to ground. Other than that the voltage just sets there ready to incite the alternator.... then when the engine starts runing the rectifier/regulator starts charging the battery. The blue M wire must kill the mag. I'm just guessing here, I don't know for sure.
 

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What is your model number?

The kill wire stuff sounds correct, now: wire from mag goes on the switch "M" terminal...gets connected to "G" when switch is off.

I don't know why they would run the regulator B+ wire to the solenoid instead of a switched terminal on the switch. I looked at some later model Simplicity wiring diagrams and they leave power on the regulator, also. So, maybe it's OK?
One thing it would accomplish is not sending the charging current through the ignition switch.
 

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Discussion Starter #8
G-1 the Kohler Magnum's model # is MV20S and the engine's Spec # is 57512 The engine is on my my Snapper 2003 Zero Turn. I'll be going out to the shop later this afternoon to check the battery voltage, I'll let you know what I find.:fing32:
 

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Discussion Starter #9

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G-1 I found the manual on a PDF file. The PDF page up and down arrows at the top of the page show the 14,18,20HP wiring schematic on page 23.... Actual manual Page 20.

My Snapper manual has the same schematic on page 22 down at the bottom of the page.

http://bsintek.basco.com/BriggsDocumentDisplay/default.aspx?filename=gdeozJvLlSZk
Thanks for the link. I noticed that your diagram does not show the regulator to be grounded. I don't know if that is just an oversight or if it means something. It could mean that there is no path to ground on yours with nothing connected to B+. If you have a Ohmmeter, you might check.
I suspect, however, that the diagram is wrong since Kohler normally fastens the regulator directly to the engine. I know that mine will not work unless it is grounded because I relocated it and discovered that little fact!

Maybe someone else can shed some light on whether having the regulator connected to the battery all the time is good or bad? To me, it's bad and I would connect it to the "L" terminal on the switch unless I could find out why not to. :confused:
 

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Discussion Starter #11
G-1 I just got in from checking the battery voltage and it's 12.75 volts so the voltage must just sit there to incite the alternator and then revert to charging the battery. The female spades, two on the stator wires and one on the B+ wire fit into a plastic insulated connector, maybe that's all Kohler thinks is necessary to be safe.


To give you more information, my regulator/rectifier's body is made of aluminum and has three terminals, the two outside are coming from the stator and the middle wire is the B+ wire.


Also, on my engine, the rec/reg is mounted to the engine's sheet metal shroud with two bolts. I don't know if that means it's grounded,you wouldn't think Kohler would use a painted black sheet metal shroud for a ground.

Perhaps I should buy a copper ground strap at radio shack or NAPA and find a bolt with a long enough stud I can just nut it down and put the other end under the regulator/ rectifier just to be sure.

Really I'm out of my element when it comes to troubleshooting small engines. I use the process of of elimination to solve my problems more times than not.

Thanks for responding to the thread G-1, I appreciate it. :fing32:
 

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G-1 I just got in from checking the battery voltage and it's 12.75 volts so the voltage must just sit there to incite the alternator and then revert to charging the battery. The female spades, two on the stator wires and one on the B+ wire fit into a plastic insulated connector, maybe that's all Kohler thinks is necessary to be safe.

To give you more information, my regulator/rectifier's body is made of aluminum and has three terminals, the two outside are coming from the stator and the middle wire is the B+ wire.

Also, on my engine, the rec/reg is mounted to the engine's sheet metal shroud with two bolts. I don't know if that means it's grounded,you wouldn't think Kohler would use a painted black sheet metal shroud for a ground.

Perhaps I should buy a copper ground strap at radio shack or NAPA and find a bolt with a long enough stud I can just nut it down and put the other end under the regulator/ rectifier just to be sure.

Really I'm out of my element when it comes to troubleshooting small engines. I use the process of of elimination to solve my problems more times than not.

Thanks for responding to the thread G-1, I appreciate it. :fing32:
My regulator is the same. I'm sure your mounting bolts will supply sufficient grounding, so you shouldn't need to worry about a ground strap.

Some wiring diagrams show battery power always on the regulator and some don't. Looks like you can keep it the way it is and not worry about it.

This was the first time I looked at this, so we both learned something!

Here is a picture of the reg. that I moved off the engine. The ground is on the backside connected to a mounting bolt.
I made this relocation because I had a regulator fail and reasoned that the cooler it runs, the longer it would last. (They do not give them away!)
 

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Discussion Starter #13
Good Idea. That should definitely help with the heat, it's exactly like mine.

The last reg/rectifier from the local mower shop cost me $56+ 7% state stickup. :crybaby:
 

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My regulator is the same. I'm sure your mounting bolts will supply sufficient grounding, so you shouldn't need to worry about a ground strap.

Some wiring diagrams show battery power always on the regulator and some don't. Looks like you can keep it the way it is and not worry about it.

This was the first time I looked at this, so we both learned something!

Here is a picture of the reg. that I moved off the engine. The ground is on the backside connected to a mounting bolt.
I made this relocation because I had a regulator fail and reasoned that the cooler it runs, the longer it would last. (They do not give them away!)
Actually, bad idea. That regulator needs airflow across the unit at all times when it is running. The older Kohler regulators that were designed to sit out in the open have fins on them. The hole in the engine shroud where it came out of gets cool air from the blower blowing across it.
 

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Actually, bad idea. That regulator needs airflow across the unit at all times when it is running. The older Kohler regulators that were designed to sit out in the open have fins on them. The hole in the engine shroud where it came out of gets cool air from the blower blowing across it.
Yeah, it's not such a good picture to show the cooling aspect, but that location is inside the cooling plenum leading to the transmission cooler. It is also the source for carburetor air and comes in thru four good sized screened vents in the hood. It should be plenty cool in there. Certainly way better than the original spot on the Kohler sheet metal.
 
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