Help! Yamaha Zuma 2-stroke idles but dies with throttle

[yamahahaha]

2005 Yamaha Zuma 49cc 2T

Symptom: Starts and idles OK cold and drives just fine when giving it throttle for 45 seconds, then dies. Re-starts and idles fine, but opening the throttle at all kills it right away. If I let it sit for a few hours, it will run normally for another 45 seconds but giving it throttle kills it after that.

Checked: spark, fuel delivery to carb, fuel mixture, idle speed, vacuum line seal, oil level, fuel level, air filter, air box, intake manifold

Replaced: entire carbeurator, air intake box and filter

Now I don't know what to do. Ideas? Thanks.