1998 Mercury 9.9/15HP 4-stroke outboards factory service manual, Page 179Get this manual
CYLINDER HEAD
5Insert rocker shafts until fully seated
a-Rocker Shafts
Oil Pump Installation
1Install oil pump using new gasket and O-Ring
a-Gasket (New) b-O-Ring (New) c-Oil Pump Assembly d-Bolt-Oil Pump Oil Pump Bolt Torque 70 lb-in(8 Nm)