1971 Johnson 40HP outboards Service Manual, Page 50Get this manual
NOTE Re-torque cylinder head screws after motor test has been completed and motor has cooled comfortable to touchg"Replace inner and outer exhaust covers, uSing new gasketsInstall all screws finger tight before tightening to specified torqueReplace bypass covers, using new gasketsUpper bypass cover has tapped holes to provide for mounting of fuel pumphInstall oil return hose on crankcase, and tighten clamps with pliersOIL DRAIN VALVE aThe oil drain valve ordinarily requires little or no attention; however, when the motor is being serviced, remove and clean the oil drain valve plate and screen assemblySee Figure 5-29bIf gum or varnish is found in the crankcase during servicing, clean the leaf valve in OMC Engine Cleaner, as it is likely that gum and varmsh have also been deposited therecMake sure that the leaf valve seats against the leaf plate, and that the screens are not cloggedReassemble and installSee Figure 5- 29Check space between leaf and leaf stopleaf stop for prope clearance of .040"
bPlace power head on exha ust housing, us ing car to avoid damaging the ends of the crankshaft nd driveshaftRotating the power head slightly clockwise as it is lowered onto the exhaust housing will engage the splinescReplace two nuts and eight screws tta ching power head exhaust housing assemblydReplace arma ture plate support nd retaining ring Replace port and sta rboard sta rter mounting bra cketse Replace shifter lock and shifter lock spring, and repla ce throttle control rmfReplace carburetor and other components of fuel syste described in Section 3