1995 Mariner Mercury Outboards Service Manual 50HP 4-Stroke, Page 58Get this manual
Carburetor Adjustments Idle Speed Adjustment
NOTE: The engine should be completely warmed up for the adjustmentCorrect adjustments can not be obtained in cold condition1Shift the outboard to neutral2Turn the idle adjustment screw on the #4 carburetor to attain the proper idling speed (750 50 RPM)
Carburetor Synchronization
1Remove M6 plugs on the intake manifold of each cylinder2Attach vacuum gauge adaptor to each plug hole