Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 78Get this manual
Float Level Adjustment 1With carburetor turned upside down and depth micrometer seated on inner ledge, check float level from top of float to float bowl flange as shown
1Turn pilot mixture screw in (clockwise) until LIGHTLY seated then back out to an initial setting of turns
aPilot Screw AdjustmentCarburetor
Float Height 1.00 0.04 in(25.4 1.0mm)