Cub Cadet ZT1 50 with Kawasaki FR691V engine that won't run right after its warm. Sputters, surges and dies

[testdepth]

The engine started surging after running and cutting for about 10 minutes. RPMs up and down and then had to engage choke to keep it running but RPMs would still hunt and then it would die.
I installed:
New carburetor
New air filter
New fuel lines
New fuel pump
New fuel filter
New gas
Removed and cleaned out the gas tank
I just installed a second brand new carburetor and same symptoms. Engine barely running and limped back to my backyard and died. Its spitting and surging and dying. WTH!!

Any ideas please help and thank you.

Engine: Kawasaki FR691V DOM 0320
FR691V J 22205
FR691V G505-R

Cub Cadet ZT1 50
MDL 17RIEACL010
DOM 01/2021
Ser # 1A05MH50046

 

[testdepth]

I just removed the gas cap and pulled it apart to clean it. The vapor hole is clear and the cap is clean so I reinstalled the cap and ran the mower. After 5 minutes with blades engaged the engine spit and sputtered and rpms dropped so I pulled the choke up to keep it running until I could park it at which time it died. It will start back up but the engine acts starved for fuel and sputters and then have to engage choke to keep it running. If I try to push the choke lever down the mower RPM drops and it sputters until it dies. This happens after the engine is warm.

 

[testdepth]

FIXED! Always the simplest thing that you check last and ends up the problem. I removed the pick up tube from the gas tank and disconnected the other side attached to the entrance of the fuel filter. I blew in the hose and watched a chunk of small grass pieces about an inch long that were acting like a plug in the tube blow out the other end. I hooked everything back up and went for a test run. Its running very smooth now and no choke needed. Thanks for the other ideas. A grass piece plug the size of a caterpillar would have and was my less guess.