1995 Mariner Mercury Outboards Service Manual 50HP 4-Stroke, Page 61Get this manual
#4 Carburetor Adjustments NOTE: #4 Carburetor Adjustments are only necessary when;
CHOKE CAM ANGLE ADJUSTMENT
1Measure gap "a" and refer to the thermal gap graphif out of specification adjust
#4 carburetor has been replaced andor Screws #1, #2, #3or #4 have been loosened or tampered with
2Adjustment steps:
aLoosen cam angle adjustment screwbFind the gap for the temperature on the graphcAdjust and tighten the cam angle adjustment screw with the specified gap "a"