Maybe the o-ring at the top of the bowl if you put it in the bowl and not on the carb.? easy to misalign the bowl while tighting the bowl bolt. You should be able to see the 0-ring if it is protruding which would cause the gas to dribble down side and off the bottom of the carb.

O-rring is in the groove where it belongs. This was assembled off of the motor, while upside down. I just RE-reassembled it & RE-reinstalled it. We'll see in the morning.......

There can be several reasons for these to overflow out the venturi, but if the worse you are getting is seepage at the bowl- it is likely the bowl itself on these. Does yours have the baffle in addition to the o-ring?

yes it has the baffle gasket & i've tried different float bowls.

The baffle is below the oring? Inverted, they will leak. You could also try it with the baffle out. I assume that it isn't leaking when the engine is not running? If I recall, new bowls aren't available for these. I carefully tweaked one once to rectify the leak. Below is a link for free parts and service info. The olden days were nice that they actually had carbs you could service and the manuals were pretty good.

Here is a link that might be useful: kohler

Start checking small details.
Use a good light source and a magnifying glass to check the O-ring groove for small pits (commonly due to corrosion).
I have saved similar carbs from the going to the scrap heap by restoring a smooth "floor" to the groove using JB Weld and have instructions for that procedure if you want or need to try.
Another thing that might have occurred is that the bowl may have "caved in" a bit (at the mounting screw location) and is not now compressing the O-ring enough to affect a tight seal. If this seems to be the case you can "straighten" the dimple by placing the bowl on a flat surface and gently striking the interior of the bowl bottom with a bar shaped drift the same diameter as the "footprint" of the bowl mounting screw head.
It is very hard to actually tell precisely WHERE the leak is occurring because gasoline is transparent until enough of it collects to form a "tear drop".
A method for pinpointing leaks of motor oil or fuel that I learned working at a motorcycle shop is to clean off all traces of the leaked liquid using strong detergent or solvent and then dry the surfaces thoroughly.
Then spray the entire suspected area with any brand of aerosol deodorant that uses a "talcum powder" formula.
The white talcum powder will darken at the spot that is leaking as soon as any liquid touches it. The change of color is less obvious if gasoline is the liquid, so you have to observe carefully, and in the case of this carb, you may need to use a small inspection mirror to see all points around the edge of bowl.
Spray the powder well above the bowl base so you will be able to see if the leak is coming from a defect that is higher up on the carb than the edge of the bowl.

Also, the Kohler service manual illustrates and instructs to check the clearance between the float body and the float "hinge towers". Says there must be a minimum of .010" clearance between float and towers using a feeler gauge to measure. Any rubbing of float to the tower could cause the float to push on the needle with too little pressure to affect a tight seal, regardless of the condition of the needle and seat.
Good luck!

Rober49:

I've just gone through a couple of Kohler "N" carbs # 26 myself.

If you did use the same needle seat & needles, try to clean the needle(s) better with a q-tip and rubbing alcohol. Sometimes the gas deposits cause varnish you can't see or barely feel. This helps cause the needle to stick and cause an over flow condition.

Also, when you seat the needle in the seat, use your fingers and twist it several times (rotational wise) in both directions. This will help to burnish the needle to the seat better.

As Mownie said, check your float level and also do the dunk test to make sure your float isn't taking on gas.

That should help a good bit.

Mownie's description of how the bowl can "cave in" on these is good and real accurate with these bowls. Yes, one would think that the fuel level is going too high if it is leaking at the seam. Once the bowl seam is fixed, they tend to stop. If they don't- then one certainly needs to go further. Double check the bowl vent as well.

Hey, quick follow up question, my bowl screw will not tighten all the way up, seems the threads are messed up inside the carb, can i go to a slightly longer bowl screw to take advantage on the good threads at the top of the shaft? Thanks in advance.

In theory you could do that.
But, if you do go to a longer screw, it would have to be the "Goldilocks" length.
Too long and the screw bottoms out leaving the bowl floppy loose.
Too short and........well, that seems to be where you are right now.