newbi needs help, please!

[rancher75440]

i have a craftsman rider, was grandads, now mine, has a kohler 26hp on it, model CV25S, spec 69526, serial 2735104591, i think its a early 90s model, it will start and idle, however it pops through exhaust, if i try to throttle up, it does not, just pops worse, sounds almost like timing is off or its missfiring real bad, it almost stops poping if i pull choke just a hair, so far i have put new plugs, checked push rods and rockers, i checked for chewed wires, compression is great, i pulled engine, pulled oil pan, thought mabye compression release was stuck, nope, it dont have one, or atleast on the cam, camshaft is nice looking, mower only has 260 hours on it, i changed voltage regulator, and oil, both cylinders are sparking, just dont know if its right, i am so lost, there is a little black box on passenger side of motor, thought it might be a cdi unit but i dont see anything anywhere that says anything about a cdi, i am a diesel mechanic by trade, just cant figure this one out, please help, thanks in advance!

 

[Rivets]

I would check the carb, sounds like a lean running condition, which clears when closing choke. This manual may be of some help. https://www.mymowerparts.com/pdf/Ko...d-CV17-CV18-CV20-CV22-CV25-CV22-CV23-CV26.pdf

 

[StarTech]

1995 model. It appears you still have an ASAM ignition system. These systems are NLA. If you suspect ignition problems use the following.

For 25 hp Engine Specifications 68XXX, or 69XXX
Order kit 24 755 308-S from your source of supply.
This kit converts the engine from ASAM ignition to MDI (magnetic discharge) ignition.

 

[ILENGINE]

That little black box would be the spark advance module. aka, SAM Could be malfunctioning causing a timing issue.

 

[rancher75440]

That little black box would be the spark advance module. aka, SAM Could be malfunctioning causing a timing issue.

is there any way to bypass the SAM and make it run like a normal small engine, just when magnet goes by coil it sparks?

 

[ILENGINE]

is there any way to bypass the SAM and make it run like a normal small engine, just when magnet goes by coil it sparks?

You have to use the kit recommended by Startech. It gets rid of the box and a few wires from the harness. It replaced the current ignition modules to ones with the spark advance that is built into the module. The modules will go from 2 or 3 wires to just the one white kill wire connected to them.

 

[Gord Baker]

If you have a removeable fuel/air adjustment needle Or 2, remove them one at a time and shoot some carb/cleaner brake cleaner in the hole and put the needle back in barely snug. Back out 1-1/4 turns and try it. Adjust this needle til it idles nice or runs WOT. Try adjusting the needle on the bottom of the Float bowl if you have one. Sounds like a very lean condition to me.