Kohler CH22 starving for gas

Some on this forum will disagree, but if Op doesn't want to pay for an oem carb, he can always try amazon and ebay for about $15. If it works, then bingo, if it doesn't you have lost little.
I know Chinesium carbs are controversial on this site, but 20 out of the last 20 I tried worked fine. Others have had a different experience, true enough. But if price is a big concern for Op, then this is merely an option for OP, and no one else!
 
For the most part, the Chinese carbs have been fine for the last several years. I used to buy the cheapest listing, had issues in the past. Now I buy one that is say $10-15 bucks more than the cheapest listing. No issues since. I still go through each one looking for deficiencies. Float heigh set proper and so on.
 
I went back through most of the posts, and this is pointing toward the fuel tank having to be removed emptied, then flushed out and left sit to dry for a couple of days. While it is drying, go back through the lines, elbows and pick up tubes.

You are chasing a globule of trash and bad fuel likely mixed with water. This stuff moves at random at the bottom of the fuel tank and will drive you crazy.

The other possibility is a cracked plastic pickup tube. Think of a bent/cracked defective straw when you are trying to drink from a soda cup. Cracks in plastic tubing expand with time and heat on riders.
 
I'm late to the party, and have not read the whole thread, but for what it is worth to the OP:

I have the CH22 (1995) too. And have had the same problem several times. Over the decades I replaced the carb, filter, hoses, checked the fuel tank's dip tube for cracks or holes, cleaned out the tank, and replaced the fuel cap to make sure it was venting.

Things that definitely helped were using the clear OE/OEM replacement filter (seems sensitive to pressure loss across the filter). My filter is factory-mounted horizontally and higher than the tank and carb, and it never seems more than half full. It is also fairly near the engine, so decades ago I made and added a shiny aluminum heat shield between, hanging from the nearby frame (to not be hot, by conduction, from the engine), and with air gaps on both sides (engine and filter sides).

The engine is also sensitive to the fuel pump, which I have replaced several times. One pump did not last very long. I'm using aftermarket ones.
 
Referring to your compression readings now, have you checked your valve clearances? Engine needs to be cool for checking and adjusting. .003"-.004" on intakes & exhaust.
 
That is a real head-scratcher. Sounds like you've already done everything but replace the whole mower! Super frustrating.

The way it runs for a while and then dies sounds a lot like a classic case of the fuel tank building up a vacuum.

I know you said the gas cap vents are clear, but here’s a super easy test - the next time it starts to sputter and die, immediately go and loosen the gas cap. If you hear a "whoosh" of air rush in and the engine smooths out, you've found the culprit. Sometimes those vents can look fine but still be clogged up inside.

Another thing I've run into on those Kohler engines is the little pulse hose that goes from the engine block to the fuel pump. That's what makes the pump work. If that hose is old, it can get soft when it gets hot and collapse on itself, or it might have a tiny crack you can't see. When that happens, the pump doesn't get enough of a pulse to keep up with the engine's demand.

Since you've been so thorough with everything else, my guess would be on one of those two things. Hope this helps you finally track it down!
 
OP admitted to having good fuel flow AT the carb inlet. Rules out the pump and filter.

OP admitted to venting the gas cap. Per OP not a vent issue.
 
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