it sounds like the engine is going to blow up while its idling....thats scary.
A rotary engine can stand much higher heat temps then that of a piston engine. When u start the engine its usually lost the heat and very cold, therefore most rotary's (besides the rx8) have a pull start aka manual choke.
I bought my rx7 for dirt cheap because the auction guys i bought it from said it wont idle. Little did they know about the car. I started it right up. They thought i was King Arthur from the Sword in the Stone.
skip to 1:25--VVV
YouTube - RX7 START UP
YouTube - REW '85 RX7 first startup