You have the "cause & effect" sort of backward (or at least, not in the proper order. I looked at the images (at photobucket link). For referrencing the images and matching the heads and cylinders, find the 6 character string in the image file name that includes XX.jpg (e.g. 68.jpg). In the images, 68.jpg and 69.jpg are matching parts. 70.jpg and 71.jpg are the other matching parts. The cylinder and head "68 & 69" show the worst carbon accumulation of the two. All 4 images indicate that the "majority" of the carbon build up is due to engine lube oil entering the cylinders via the INTAKE VALVES. The intake valve seals are likely worn out or cracked. The valve stems and valve guides probably have wear as well. When I started off stating that you "may have it backward", I mean that the carbon build up is caused by oil from the intake valves. Subsequent "flaking" or shedding of some of the carbon.....is the CAUSE of the very minor scoring in the cylinders. The carbon build up is NOT the RESULT of the scoring. Look into the intake passage (you'll need to have the intake valve open) and you will probably see a good bit of build up of "gunk" on the valve and around the valve guide. It is also possible that you do have an "over-rich" mixture. If the mixture is excessively rich, your intake valves and passages "MIGHT" be somewhat "washed clean" of the expected gunk (solvent washing from the gasoline in the intake draft), so the build up of gunk could be less than I think you will see. Whether you actually "FIND" a lot of gunk build up in the intake valve passages or not........the "wet tracks" leading FROM the intake valves "tell the story" of the root cause of the carbon source. You say the engine "was overhauled" about 4 years ago. Was the valve train addressed then or just pistons (rings) and cylinders (honed)? The scoring in the cylinder walls is so slight that I doubt the scoring itself is adding to the problem. I would bet though, that the piston rings may be so "carboned up" that they are not "free to inflate" as they should and that the oil control rings have also become ineffective from carbon clogging them.

The pictures do not show the scoring and apologize for that. I did think the carbon came first and scored the cylinder which is why it may be burning oil. I think the engine just had new rings and was honed, will check on that. On the intake side of the valve it is carboned up pretty bad too, can the valve guides be fixed and if so how much work is it?

Pics 68 and 69 are the problem, I dont believe the other side is burning oil yet.

"can the valve guides be fixed and if so how much work is it?"***** That is something that you will need to ask a small engine shop that is near you. I don't think you would have much trouble finding valve guide seals, but valves and valve guides may be a problem (if needed) because the Kohler site has this engine listed as "retired". I believe that means Kohler no longer supports this engine with replacement parts. But, "New, old stock" parts might be available, or aftermarket parts may be available, but you would have to beat and shake the bushes to scare them up. Your valves and guides may be "OK" and new seals may be able to end that problem. There may be problems in the cylinders themselves (and pistons) due to the abrasive nature of the carbon particles shedding after building up. Having this much carbon, and a "renewable source" of carbon, is similar to running the engine without an air filter in dirty/dusty conditions. Because the crankshaft (by nature) imposes a lateral load on the pisto and cylinder walls during a portion of each revolution. This cause the cylinders and pistons to wear more at the bottom of the cylinder and the bottom of the piston skirts. This is called "Taper wearout". Tapering of the cylinder makes the cylinder larger at the bottom but it makes the piston skirt get smaller. All this wear means that eventually the piston is sort of wobbling in the cylinder instead of gliding straight up and down. All this extra movement (and in the wrong directions) makes it impossible for good compression and oil control to take place. Looking at all the things that can plague an old engine, you may find it cheaper to replace the engine, than to address and restore/replace all the problem areas on an old engine. Or you could take the engine completely apart and have everything cleaned out good and put in new seals, gaskets and rings. If you decide to go the "cheap route", I stress that the cleaning out of all parts should be done "professionally" using powerful solvents. Piston cleanliness is a step that often gets "skimped on". If reusing old pistons, they need to be cleaned in a dip carburetor cleaner. If the pistons are not cleaned this way and thoroughly, carbon particles in the ring grooves and oil holes are right there where they will do immediate damage. I have thought about your engine and I think that it is likely the valve seals leaking oil could well have been the original issue 4 years earlier. Couple that with the typical shade tree re-ringing procedure, and the effort put into that "repair" may not have solved anything. It just delayed and prolonged the inevitable.

"I dont believe the other side is burning oil yet."***
With the amount of "oil slick" leading from the intake valve on "the other side", you can bet that cylinder is burning oil also. It just may not be to the extent of the side shown in pics 68 & 69.