Futaba 10J - Manual (Page 147)

This mixing sets the mixture by a 5 point curve in relation to throttle
stick movement when the engine is equipped with a mixture control
system (needle control or other mixture adjustment). Normal condition
(NOR) idle up use (ID2) and idle up 3 (ID3) can be set independently.
The needle servo connects to CH8 of the transmitter.
7+5 ڀ 1(('/