1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 122Get this manual
Bleeding Air from Oil Injection System IMPORTANT: If air exists in either oil pump hose (inlet or outlet), the air MUST BE bled from the hose(s) before operating engine
Oil Pump Test
NOTE: graduated container is required to perform this test1Connect engine to remote fuel tank containing 50:1 fueloil mixture (25:1 if during break-in period)2Attach flush device to outboard or place outboard in test tank3Remove top cowling4Disconnect oil outlet hose from fuel pump fitting5Plug fuel pump fitting6Remove link rod end from oil flow regulator7Rotate oil pump regulator full counterclockwise and hold it in this position, (wide-open pump position)8Attach an accurate service tachometer to engine9Place end of hose into graduated container
Bleeding Air from Oil Pump Inlet Hose
1With engine not running, place shop towel below the oil pumpLoosen bleed screw three to four turns and allow oil to flow from bleed hole until no air bubbles are present in inlet hoseTorque bleed screw to 25 lbin(2.8 Nm)This procedure also allows oil pump to fill with oil