In attempting to adjust the throttle friction on my Yamaha 704 remote control (single binnacle(?), circa 2000), I found two apparent adjustments: (1) a pair of slotted, threaded shafts each with a jam nut on top of the unit and (2) a single, slotted "knob" at the base of the unit (all found after removing the unit cover held in place with four screws). Can someone please tell me the function of these adjustable items?