Throwing expensive parts at it is obviously not the answer. Have you run a compression or leak down test? A valve could be sticking when it gets hot. Are the modules properly grounded?

In accord with canguy. Do a "poor boy" leakdown test with the valve cover of the affected cylinder removed so you can observe if the head gasket might be defective into the pushrod gallery. Might also want to check the crankcase breather per the instructions in the Kohler Service Manual.
Another note of possible interest in regard to crankcase breather malfunction: Looking at the CV engine (vertical crank) it appears that the intake manifold may be oriented with a "bit of tilt" toward the lower cylinder (Cyl # 2 according to Kohler). If this is the case and the breather was allowing too much crankcase blow-by to be channeled into the intake system, there could be a tendency for the oil mist to settle out of the draft and then trickle in a fine stream along the intake manifold toward the cylinders. If the branch of the intake manifold serving #2 cylinder is slightly downhill, the small amount of oil would make the diet of #2 cylinder richer in hydrocarbons than cylinder #1. Of course, this is all conjecture on my part! So far neither person (in this forum) with the problem has declared WHICH cylinder is "rich", only that one is richer than the opposite.

Here is a link that might be useful: CV manual

It is the side with the dipstick tube that is rich. I did not buy all the parts I do have another mower and swapped the coils and carb. The compression in each cyl was 120. I just pulled the head off and it is hard to tell if the gasket was bad. It is not really using any oil, it is rich with fuel. The piston and conbustion chamber is loaded with carbon. There was another post on here and the guy had the same problem and never posted the answer to his problem if he figured it out. http://forums2.gardenweb.com/forums/load/tractor/msg0818294426861.html?

***"It is the side with the dipstick tube that is rich."***
Well, that blew my theory of "stuff" runs downhill! The cylinder near the oil dipstick is cyl # 1, and it is at a higher altitude than cyl # 2. At this point, you can only clean up the head and hope a new head gasket solves the issue. While you are in the inspection mode, take a good close look at the intake valve stem area that is visible looking into the intake port of the head. If the valve stem and inside surfaces around where the valve stem meets the valve guide have a heavy, gummy looking crud on them, you need to replace the valve guide seals. As to the other guy not ever posting back with results......it happens all too often on forums.

I took the head off and the gasket appears to be good. Valves and guides and seats look good as well. Any other ideas would greatly appreciated before i put it back together and hope the new gasket fixes it. Thanks....

I rebuilt a CV624S yesterday (grenaded both rods) and found one cylinder quite rich due to a leaking intake gasket. This would produce a vacuum leak and the results you reported.

***"found one cylinder quite rich due to a leaking intake gasket."***
OK, possibly we might be going in the right direction here. Which cylinder had the leaking intake gasket and how did you determine it was leaking "after the grenade exploded"?

I just picked up a gasket kit and 2 lifters for the heck of it because im in there, plus they were only $9 each. No sense doing it twice, hopefully one of the two will do it. I will keep you posted. Cross your fingers!

Well its done and guess what...... Same problem????? What else is left?

Does either this engine or the donor engine have smartspark? Were the breather reeds inspected when it was apart? Model spec numbers?

Model cv23 spec 75582. No smartspark... and the reed on the side that is fouling was checked and cleaned.

So to recap- you pulled the 1 head only, checked the reed and cleaned plus swapped various components to no avail- correct? The module installation verified by the manual? New intake valve seal installed? My other thought goes back to the breather system not working well and this cylinder is the weak link so to speak. On the breather cover if a new gasket was installed or sealant, dipstick seals in place and try swapping the breather canister. It would be worth a call to Kohler to see if they have seen similar cases.

Here is the deal. Lets start with how it runs. It idles perfect, does not use any oil. As soon as you throttle up you can hear that it sounds like it is holding back just a little, as soon as you give it throttle quickly it sounds like the choke was thrown on (but it is not), it also will pop out of the carb and run rich and smoke black. #1 cyl plug was black... I immediately thought module, spark plug, so i replaced, same thing no change I then replaced the carb and still no change. So i pulled that head and the piston and combustion chamber is loaded with carbon. I cleaned the piston and head and inspected everything visually and it all seemed good. So I picked up a head gasket new nuts and washers also while I was in there I decided to just eliminate the lfters so I bought new ones (cheap enough), I got it all back together and same thing. I dont get it, I am mechanicly inclined as I worked on cars for years but this has me stumped. I really dont see whats left. Also both cyl have 120 psi. Ar you talking about the breather on the valve cover?

Sounds like a baffle in the muffler let loose and might be restricting the one side.

I actually did that too. I unbolted the exhaust that is what i tried after the module carb and plug

If you are saying you have hard carbon deposits in that cylinder, you have oil burning itself to a crisp I would think. How does it get in there? Past an oil ring? Internal pressure pushing oil into the combustion area through the reed and intake valve seal? I'm not huge on twin engine breather theory with what exactly happens if the canister doesn't function or extra air is being drawn in to the crankcase. The breather cover I was refering to is between the two heads. Some had used sealant, yours supposedly came with the print gasket-which is what they want you to use anyways. Maybe that's why Kohler likes the manometers. How long does this run for before it kills the plug?

I am pretty sure I figured it out. I looked up the specs on the cam and it appears that both my exhaust lobes are worn. I ordered a new cam and I will have it saturday. I will have it done by saturday night and will keep you posted.

It seems the tenacious Doctor Mopar has dug deep into his bag of knowledge here.
I found the camshaft lift specs listed as, Intake and Exhaust Valve MINIMUM lift- 8.07mm (0.3177") or, roughly speaking, "about a hair over 5/16", if you like fractions.
Doctor, what did your cam lift measure out to? And what instrument/tool did you use to get that?
This, and some other threads in recent past, seem to lend creedence to a notion posted by a member regarding the reduction of "Zinc compounds" in the formulae of motor oils that was done when the latest API designations were put into effect. I don't recall every detail of the post but the concern was that camshaft wear might become more common following reduction of Zinc in the oil additive pack.??? Are the chickens coming home to roost? or is it just another example of "cheapening" of quality in components, or a little of both?

After I looked up the specs on the cam and saw that both intake and exhaust shared the same lift. So when i pulled the valve covers and pulled the plugs I rotated it and it was obvious that they were not even close to the same. I measured it with a dial indicator and my intakes were just at 8mm and the exhaust were at 3mm and oddly enough i was relieved. As far as the oil theory goes I am not sure although i have heard that myself. All I know is I have 2 23hp kohlers one a 2001 and this one a 2005. I change my oil in both machines at the same time with the same oil and filters. My older one has 2500 hours and never had to do anything to it accept a stator. This one has 1000 hours and always smoked on start up and never seemed as good as the older one. Maybe its one of those Monday morning or Friday night built motors?? (LOL) If i was to guess im gonna say lack of quality parts. However it is not fixed yet so i will post what happens when i am done with it. Thanks

I did not know it has a compression release. I remeber them from quads with a kick start, these are only 8.5 compression why would it need that? The build up was hard leaning towards oil.

***"Compression release is on the exhaust side on these. I wonder if you will find lobe wear or damage on the release."***
From your use of the dial indicator, your measurements should be very true. You should also be able to "detect" the ACR pin on the exhaust valve cam lobe as you roll the engine over by hand. This will show up as a "bump" on the dial indicator. The ACR pin protrudes from the cam shaft in the "base circle" region of the cam lobe (actually the base circle center is opposite the peak lift point of the cam lobe). Using that bit of info, your "real measurement" of the exhaust lobes should be made off of that "bump" to make sure you are not just measuring the max point of the ACR pin, and thinking you are on the base circle. The difference in height of the exhaust lobe might actually be only 3mm more than the ACR pin max height. Just something for you to confirm maybe.

GOOD NEWS!!! It is running good now..... FYI it does NOT have a ACR. But the good news is that the cam was wiped on both exhaust lobes and the intakes were slightly worn. The only issue now is that it has a slight bog on throttling up and on a fast deaccel it will backfire out the exhaust with a flame but if go down slow its fine. Other then that she is fixed....

Thank you doctor. Good info.

i have a command pro 26 fuel injectors and it running to rich can any body help me with that