As w8ye said over 300F is getting too hot and my Hyper 50 in the Raptor runs between 190 and 210 on 30 percent fuel when properly tuned. You can comfortably hold your finger on the backplate immediately after landing from hover for about 3 to 5 seconds. (engine still idling) If you can hold it on longer it is probably too rich, less it is probably too lean but that is not written in stone. It is more of a get you in the ballpark type thing. It takes a little patience and it helps to have an experienced heli pilot to show you how to get it tuned just right. Good Luck getting her dialed in. [8D]