1988-1992 Mercury Force 5HP Outboards Service Manual, Page 151Get this manual
2 Install power head on motor leg Lubricate driveshaft splinesAlign driveshaft splines with splines in crankshaftMake sure spline seal is in place in crankshaft
NOTE: Do this by shifting into gear and slowly rotating the propeller Apply sealant (Special Tool NoT-8983) to threads of six screws securing motor leg to power headInstall screws (A)Torque to 70 inlb(7.8 Nm)