Small Engines (Lawn Mowers, etc.): Kohler engine doesnt run great, crank case, little holes

Question
Hello John,
A few months ago I informed you about A Kohler engine CH20S Spec# 64547 with a oil pressure problem. You advised to change the oil pump because the relief valve probably was stuck and you had it right that problem is solved. Now I put the engine back in the mower it's a Deines Magnum mower with a 72" mower deck in the front, but the engine won't run great it looks that it makes not enough RPM with the throttle full open and it sounds like a short of fuel. It start perfect but with low RPM and you turn on (Electric) the mower deck, it shut down it has not the power anymore to run the mower deck or to keep the blades turning. you can drive with it hydrostatic no problem. When I look in to the carburetor a lot of fuel is coming out of the jet and the fuel is splashing out of the carburetor on top where the air filter has to be. I changed already the 2 little O-ring in the carburetor those are around a sort of a jet with al little holes in there (advise from the manufacture)for changing the oil pump you don't have to take the engine apart only one piece of the crank case so I didn't take cylinders or the timing apart. I checked compression, ignition and I have a strong spark, do you have any idea what can be wrong. The customer told me before it runs great.
Thanks for your time.
Fred

Answer
It was another John a few months ago, and the first assumption would be a carb problem.

  Just bear with me though, unplug one plug wire, then try to start.

See if it runs, then try the other side.  If it runs one way and not the other, then you know which way to look.

Let me know what you find.