No spark at plug

[VegetiveSteam]

Yep, I appreciate mankii's post about the DSAI unit available at "totalwireframe.com" for a cheap $66, but something seems fishy about that website. Even mankii pointed out that "totalwireframe.com" claims to have 250 units available. It just seems kinda crazy that they would have 250 units available.

It's a bogus website. About 6 months ago that same website was selling a 750ml of Blantons for $49. Yeah. Right.

 

[TobyU]

The most surefire way to test a coil is to take the shroud off to get to it and unhook the small push on wire from it which is the kill switch.
Note that this disables always of turning off the engine so if it does start be ready with a glove or a towel to pull the coil wire off the plug to stop it.

Very rarely though, is this the case but it's always worth a shot.

I had a whole slew of these coils going bad a few years ago and it was just because they were all coming up on 20 years old and while they were good coils, they were just old.
Most would not spark at all but some would spark about every third revolution but not nearly enough to run or even try to run but occasionally give you a little pop.

I don't recommend buying the genuine Kohler coil because it's probably made in mexico, India or China anyways and even if it is made in the us, I can almost guarantee you that a new coil you buy today in a cold box will not last as long as the coil did on your mower originally.
So get the part number from the coil or from the machine and look up the proper part number and order one from eBay or Amazon from the cheapest seller you can find.
I was buying all the ones I was getting for between 32 and $36 shipped to my door.
They're still running just fine.
Of course, first check with another known good plug and preferably a used plug because it's far easier to see spark on a dirty plug and than a brand new one.

 

[TobyU]

All this talk of safety switches and arguing back and forth..
Who cares at this point. The first thing to do is to test your coil and see if it's good or not.
I gave the method of doing that in my first post.
Also, keep the ohm meter put away because that test is worthless for a coil and it's just a very very basic one at best.
You simply can't trust a coil that owns out okay on a digital ohm meter to really work properly and real use.
You can find gross where you know for certain that coil won't work but there's too many of them that check fine but fail an actual operation so don't bother.

 

[Etbrown44]

I like TobyU's approach. Plus, be sure to test a new plug before you spend anything. Way too many guys have bought coils they didn't need, because often you can't see even a good spark in daylight.

 

[VegetiveSteam]

The best way to troubleshoot anything is to make sure you understand how the system is designed to work before you start.

 

[bertsmobile1]

Your module is gone
They are a great idea because they allow for a much better advance curve so you get better torque because when the engine sped drops, the spark retards .
However they do not last for ever because they do the advance / retard bit by tossing in some gates & resistors.
Remember electricity can not be made to travel faster, only slower.
So these bits eventually burn out.
Shame, but that is the way things go
So the conversion you have been advised to do is your only option other than replacing the engine .
Nothing you buy today will be any where near as good as the mower you currently have .

 

[closecut]

The rust and trash in the fuel cutoff solenoid can physically jam the solenoid and prevent it from working properly.The seat switch is a common problem.Put a jumper across the wires of the switch and see if that solves the problem.If so,replace the switch for safety.
Kohler had lots of problems with the DESAI ignition,and finally abandoned it and replaced it with the old fashioned grandpa version ignition system..back to the old reliable.
All the DESAI system did was delay the firing of the plug.The initial timing was set high, and the delay was long,so timing was low at starting, to allow easy starts,and as the engine increased speed,the system decreased the time delay on the timing,thus advancing the timing.If the battery is border line,you may have trouble starting due to the high timing with the old fashioned coil.AIso, advance the coil a bit by loosening the screws,and moving it in the direction of rotation as far as possible,thus reducing timing, then resetting the gap.There is not much clearance in the coil screws,but a lttle goes a long ways on timing.
There will not be a noticeable difference in performance from my experience.

 

[closecut]

The rust and trash in the fuel cutoff solenoid can physically jam the solenoid and prevent it from working properly.The seat switch is a common problem.Put a jumper across the wires of the switch and see if that solves the problem.If so,replace the switch for safety.
Kohler had lots of problems with the DESAI ignition,and finally abandoned it and replaced it with the old fashioned grandpa version ignition system..back to the old reliable.
All the DESAI system did was delay the firing of the plug.The initial timing was set high, and the delay was long,so timing was low at starting, to allow easy starts,and as the engine increased speed,the system decreased the time delay on the timing,thus advancing the timing.If the battery is border line,you may have trouble starting due to the high timing with the old fashioned coil.AIso, advance the coil a bit by loosening the screws,and moving it in the direction of rotation as far as possible,thus reducing timing, then resetting the gap.There is not much clearance in the coil screws,but a lttle goes a long ways on timing.A vaccum advance would have ebeen much better,IMHO,like in older cars.
There will not be a noticeable difference in performance from my experience.