Kohler Command Smart Spark Ignition.......
 

The Smart Spark ignition system was used on some 22 and larger HP Kohler V-Twin engines. This system is known to be flawed and problematic. Can these engines be retrofitted with the ignition systems used on the 18-20HP engines?

Seems that I read, that could be done.

Sam in the SME on this....

Tim

I did a CH22 SAM to regular swap a few years ago. All I did was to replace the Mags with the standard type. I was under the impression that you would also need to replace the flywheel to make it run properly but I just looked up the part numbers for the flywheel for a regular CH22 and they are the same as the SAM engine. If I was going to do another one I'd probably buy a new wiring harness and a couple Mags and have at it. The mags bolt in the same place as the SAM stuff. Just for kicks I'm going to dig into this a little more.

Sam,I would be interested in what you find out on this. I have a CH20 in my 782 that came with the Sam system and the guy I bought it from changed it over to standard but did not change the flywheel. When you start it up it acts like the timing is advanced and wants to kick back on the starter. When I questioned him on this he said that Kohler had three different flywheels and the difference was the location of the keyway. He sent me a different flywheel but I have never installed it as I learned that if I start it at an idle and do not choke it until it is spinning it will start ok. I have noticed that it seems to have much better throttle response and lugs better than my other CH23 in 1872 #1. Reminds me of advancing the timing on a small block Chevy and having trouble starting it when hot.
Tom

Looks like Kohler has a lot of combos. I would need the info off the engine to try to try to find the proper combination of flywheel and mag. :beerchug:

Thanks for your replies. Sam, my CH25 ID numbers are as follows:
Family SKH725U1G2RA
Model CH25S
68515
Serial# 2611502677

What research I've done leads me to believe most Smart Spark engines use a different flywheel. I'd bet they are keyed with more advance than a normal mag ignition Command. Hope we can figure this out.
I think it's possible to use 18-20HP flywheels and coils to eliminate the Smart Spark. This is just an assumption on my part so I hope we can confirm a retro fit that will work.
Thanks in advance.
Tim

Tim

Did a little research. Your engine was built for Bunton.

https://www.jackssmallengines.com/ja...25-hp-18-61-kw

I looked at a bunch of different CH25 flywheels and ignitions, they all seem to use the SAM ignition. So then I looked at crank shafts between CH25's, CH23's and CH22's trying to find on that has the same crank as what you have. Figured if I could find one that didn't have the SAM but used the same crank it would tell me what flywheel to use. No luck so far. I'm concerned that if you use something like a CH18 flywheel you could end up with a balance issue.

If you want to continue digging maybe you can find something.

https://www.jackssmallengines.com/ja...5-ch-cv620-750

You may want to contact dvogtvpe, pretty sure he has some experience with the V-Twin Kohler's built for pulling

the smart spark unit is a ignition delay unit ( which works reverse of its wording ) , at low speeds its about 5* advance and advances the spark slowly till 15* at 3600 . the more advance makes the more top end torque , cleaner emmisions and runs cooler . in theory its supposed to be like a weight advance unit .. kohler has a section on it in some of there manuals . some of the ones I have converted back to standard mag units , we seperate the starter from the ignition , spin the motor over , then turn the ignition on . and the motor fires . I haven't tried to use a offset key like we do with cars yet .

Interesting way to deal with it. I wonder if it's worth a call to Kohler to ask if they have a recommended swap? My guess is they do but won't tell. I'm sure if you could mount a degree wheel on the flywheel of a properly operating SAM equipped engine you could find the point that it fires at 3600RPM and then compare it to the time it fires without the SAM then determine where to cut the keyway in the flywheel. Maybe Mid West Super Cub has played with them. :bigthink: