New AC1377sy. First run broke transmission belt due to stick. Replaced belt. Started, drove across yard, tested cut, no problems. Drove to garage. Stopped and shut down. Next morning, Placed throttle in choke and started engine. Only ran in choke. Stopped and restarted. Only ran in choke. Stopped. Checked all known considerations. Tried to restart. After numerous tries and many checks. No luck. 4 old farts checked every thing. From rear to front and under. Had gas, spark, no known seat, break, etc problems. When replacing the transmission belt, is there any thing I might have missed that would cause this problem. I am very old, but have had several tractors.