My Generator Won't Start

[MikeBob]

I have a Kohler 12kw standby generator where the control board went out. The part cost over $850 to replace, plus labor. A new generator cost approximately $3000. It did not pay me to spend over 1/3 of the cost of a new generator to fix a 10 year old unit. I bit the bullet and bought a new one.

Your math is a bit off
  Then if you have to add disposal and install cost even more off.

[crokett™]

Dumb Q:  Have you tried starting the generator with the (cable) harness to the board disconnected?

Where to the leads from the harness go?

Also dumb Q:  Is there a schematic for the board available from the manufacturer?

Yes.  It didn't do anything.  The board is part of the ignition circuit.  FWIW, strapping across the starter solenoid the starter turned over 2 weeks ago.  I didn't do it for long enough to see if the generator ran.  

The leads from the harness go down to a wiring block, where the leads to a transfer switch would go.  Long story but I don't have the transfer switch and never intended to.   My intent was always to run this manually.  I have more in the propane tank and wiring back to the house than in the generator itself.  

Schematic is buried somewhere on page 3 or 4 of this thread.  
 Here's a screen capture from the PDF of the troubleshooting manual

   

[blackhat]

Could you?  Theoretically, yes, but, you would have no engine fault safeties and more importantly, no generator output fault safeties.  The first hint you might have of a generator fault would be the magic smoke coming out of whatever is connected to it.

[MikeBob]

Your math is a bit off
  Then if you have to add disposal and install cost even more off.

Well not maybe when you figure labor on the board install. I missed that.

[Phil Thien]

I agree w/ blackhat.

But can you trace where Pin-7/Wire-14 goes?

It seems from reading this this:

http://www.pmtech.org/document_center/Br...Manual.pdf

Especially p. 26, that once the control board is satisfied inputs are in-range, that this is the output that says "go."

But I could be entirely wrong.

Just curious if it is possible to see where that lead goes.

[Roly]

If it just that one part that is bad you may be able to get the part number off of the one directly below it.  Looks the same.     Since it is no longer available Briggs may have a schematic for the control module itself that they would share.   A electronics place may be able to repair it if that is all that is bad.    Can you see if the part itself failed or the smoke trail also goes to the connector on the board where something there may have failed.    Roly

[Phil Thien]

A lot of components look alike but are functionally different.

I tried looking at images using the supplied board p/n but couldn't find anything hi-res enough to read a component p/n.

Maybe Briggs could supply that.

If the component can be sourced form Digikey or Mouser or eBay, it would make sense to swap it and give it a spin.

[Roly]

I'll agree with Phil they can look alike but be electrically different   Looking at picture on page 20 of the manual the surrounding circuitry looks very similar.   Both appear to be SCR's that switch on and off.    While you did not have any line voltage nearby could a ground have hit it while the 12v battery was connected ?    It is item 04 on the circuit board with item 05 which looks the same next to it, however I cannot see any part number on the item.
 Suggest checking the back of the board for damage in that area.  
 It seems as the same board was used in various brands of generators but all seem to be discontinued.   I doubt if B&S has a list of component parts on the board itself but they may be able direct you.     Roly

[crokett™]

Could you?  Theoretically, yes, but, you would have no engine fault safeties and more importantly, no generator output fault safeties.  The first hint you might have of a generator fault would be the magic smoke coming out of whatever is connected to it.

Yeah. I thought about that, but I also know that my 5KW gas generator does just fine without all that, at least AFIK it doesn't have any of those.

If this doesn't work the wiring isn't wasted, I can still use it for my 5KW generator, it just won't run the heat pump in the winter. The old house this wasn't a problem since I had a woodstove. I could probably also convert it to propane and turn it into a semipermanent if I wanted to.

[blackhat]

You need some way to control fuel flow and shut it off if the engine dies. Remember LP is pressurized.