I'm in agreement with Mr. Reivers. There seems to be a bit of confusion here between poor tuning and engine heating. You cannot use the mixture as the primary means of carrying away waste heat. It cannot be done in our applications without tremendous volumns of fuel passing through the engine, and fule of a different type at that.

Make sure you have positive airflow through the engine and ample exit area for the heated air to escape. A baffled engine stays cooler than one without, and an engine tuned on the lean side will over heat faster than one properly tuned..