Hi Joe, Almost certainly it was carb icing, the evapouration of gas in the carb cools the throttle body dramatically, - even on a warm day.
In UK it is probably number cause of in flight engine stops, and the circumstances of your stop are exactly consistent. I have had it happen to me twice, the first time on roll out - only 50 yards from the hangar, the other time I was doing a practice forced landing. It all became very real, and I ended inverted in a muddy field, luckily my Luton Minor being a sturdy old girl took only minor damage. Tight cowlings are an old wives tail, the only way to stop it happening is fit a carb heater, or fuel injection. There is a very good article on carb icing here http://www.caa.co.uk/docs/33/SRG_GAD_WEBSSL14.PDF Pete Diffey St Albans, UK