LX 50 4 running problem (2007)

Would appreciate ant help or ideas.

Scooter starts and runs fine for 5 to ten miles.

If I slow and idle, engine will cut out. It will re start if I hold throttle open, but not enough power to run.

If I keep throttle open after three to four minutes the engine will pick up and run fine again, then the pattern will repeat.

Exhaust feels very hot.

New Battery.

Changed vacuum and fuel lines.

Cleaned air filter

Cleaned carb

New Spark plug , new CDI unit and HT lead

Thanks for any suggestions