Kohler Command Pro 27 about to head to the scrap yard LOL

I had another thread posted here about this motor. It wouldn't start and was spitting back fuel. I've solved the previous issue (fuel spitting back was from throttle getting stuck, I forgot to transfer over one grommet from the old carb). It will start now, reliably, every time. Little bit of choke and it fires right up. Idles good. As soon as you start mowing under load, it hesitates, bogs down, almost stalls. Pops/backfires on occasion.

Here's what has been done so far:
1) New...

Kohler Command Pro 27 about to head to the scrap yard LOL