火咀:cold- for the fuel that with high percent~! eg:30%,35%
hot - for the fuel that with normal percent~! eg:10%-25%
and brother,i think that the normal engine temp is aroud 100 degree~!
i can only answer some of your question because i am not professional,i am only
12 years old~!
if you are free,you can play with me,i play FW-05T~!