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Intek Twin in a JD 140D Model 445577. Found that someone disconnected the coil ground wires so the mower would just shut off after the fuel solenoid cut off the fuel. I reconnected the ground wires to the coils and no spark. I disconnected the engine from the tractor harness, still no spark. SO what I have now is just the black wire from each coil, tied together and running back to the factory plug. Still no spark...Here's the funny part- If I unplug EITHER ground wire from any coil, I get spark. I only have no spark if BOTH ground wires are hooked to the coil terminals. The black wires have been checked for chafing, and are in fact held away from any metal surface all the way to the plug. Anyone ever seen this?

What you probably have is the steering diodes in the harness are shorted allowing each coil to kill the other coil. Replacement of this harness should solve the problem.

Thanks, I replaced that small harness to the coils/solenoid. It still won't kill spark when I turn the key off. I disconnected the engine harness again, got a jumper to keep the fuel solenoid energized. I went right from the black coil wire to ground, still had spark. I'm lost!

So you went from no spark with harness connect to with the new harness no spark kill then you have coils that have failed. Kinda rare that both would failed at the same time.

The coils are good, they spark all the time. If I short each coil individually, they kill out. It's when I have them hooked to the engine harness that they don't kill.

Would aftermarket coils not work properly with that diode harness?

Have you tried hooking the harness up both ways ?
Did you get the harness with a diode , you can see it as a thick lump in the wire ?
Does the ground wire actually go to ground when you turn the mower off ?
not unheard of t have the ground connection at the key switch fail .

Of it may just the way JD did their side of the wiring harness as I have seen a few JD done this way.

Not sure what you mean about hooking the harness up both ways? It does have the diodes. I've tried directly grounding the engine harness to ground with a jumper wire, and both coils still have spark. The key switch does shut the carb solenoid off as that's the only way the machine shuts off at this point.

Can you still kill the individual coils?

Each individual col will short out on its own. It's when I plug into the diode harness that there is always spark.

Something not right with the harness if you are ground the free end with two ends with diodes attached to the coils. It should kill them ; unless, someone put the diodes in backwards.

I got the harness directly from Briggs. That's why I'm stumped.

If you got a meter with diode check, check the diodes. Cathodes goes to ground; Anodes goes to the coils.

The sub harness from the engine plug to the coils on some mowers can be hooked up 1 then 2 or 2 then 1 .
I know this because I have done it .
The diode in the between only chokes in one direction.
So if you hook it up 1>2 in place of 2>1 then it might not work .
Some will fit either way & some won't .
Being a used mower there are all sorts of work arounds that can crop up.Obviously the DPO was having a similar problem which is why they were disconnected in the first place.
I will see if I have a wiring diagram for it on file .

Not sure what you mean by 1 then 2 or 2 then 1? The harness only goes one way, unless you mean order of connection? (coils then harness to tractor or vice versa). Do you think Briggs would mess up the diode direction?

If your s will only hook up t the coils one way then you are good.
Had some where the sub loom that had the coil kill wires & solenoid wires could go left coil the right coil or right coil then left coil

I measured the harness, .68 one way and 0L the other way on both diodes using the diode setting on my DMM.I don't understand why this won't shut off...

Okay check this. At the end that you normally ground put on the negative lead and each coil (one at a time) You be getting the .7 +- reading. reverse the leads and you should getting OL. IF you don't then the lead has the diodes backwards; otherowrds' if you get .7+- reading with the negative on the coil(s) terminal and red lead at the grounding point.

So I plugged the wires into the coils. I get .546 in diode mode on the DMM with the RED lead on the "ground"end of the harness, and the black lead on the coil terminal. Reversing the leads gives 0L. Thanks a bunch for the help so far.

That is your problem the diodes are reversed; never will ground the coils. I wonder what idoit put the harness together.

Mr. Briggs and Mr. Stratton! LOL. I'll reverse them and try it.

It worked! Quality control is a little off at B&S!! Thanks so much for the help!