83.5 WBXR  Normally runs strong, starts easily.  Last week was unseasonably high temps. Started fine. Drove in from the RC Field via highway at 80 to 100 KmPH no problem. In city traffic it started to "flutter when coming off idle. ( Press accelerator and it would not rev- not firing- Work the gas pedal  out and in and it would catch. Finally stalled and would not re-start. Waited ten minutes and started easily, ran strong until it got hot again and started stumbling again. Repeated the wait ten minutes and ran strong again. Temp gauge read normal. Fresh fuel. Baffled...
Any ideas as to what may be causing this???
 TIA
Don
"Try to learn something about everything and everything about something." -Thomas H. Huxley