Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 77Get this manual
Idle Speed Initial Setting (cont NOTE: Before adjusting idle speed, make the full throttle link rod adjustmentSee procedure precedingREMOTE CONTROL MODELS 1Disconnect the remote control cable from the throttle armPosition the throttle lever to idle position2Back the idle speed screw off of the throttle lever so idle speed screw does not touch lever
Pilot Mixture Screw
(NOT APPLICABLE TO BODENSEE MODELS)
NOTE: The pilot mixture screw is set at the factory and normally should require no adjustment1If adjustment to the pilot screw is requiredadjust screw as follows: aTurn pilot mixture screw in (clockwise) until LIGHTLY seated then back out to an initial setting of turnsbAdjust pilot mixture screw for best performanceWith engine running at slowidle speed in "Forward" gear, turn mixture screw "In" (clockwise) until engine starts to loose R.P.M then back out 14 turnaIdle Speed ScrewThrottle Lever