1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 109Get this manual
CLEANING AND INSPECTION
1Carefully inspect carburetor body and fuel bowl for cracks, stripped threads, plugged or restricted passages and passage plugs that show signs of leakage2Thoroughly clean all carburetor parts with mild cleaning solution (that will not damage rubber or plastic) to remove dirt, gum and varnish that may have accumulated3After washing parts, blow parts dry with compressed airBe sure to blow air thru all passages, orifices and nozzles4Check float hinge in the float pin area for wear and check float for leaksReplace parts as necessary5Examine inlet needle for wearIf worn, replace with new inlet needle
S Install mixing chamber cover and gasket as shownS Install low speed mixture screwS Install bowl vent jet (back drag) (3-Cylinder Models only)