1971 Evinrude 40HP outboards Service Manual, Page 50Get this manual
NOTE Re-torque cylinder head screws after motor test has been completed and motor has cool ed comfortable to touchg"Replace inner and outer exhaust covers, using new gasketsInstall all screws finger tight before tig.htening 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 .clampJ3 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 Accessory Engine Cleaner, as it is likely that gum and varnish 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 stopBend leaf stop for proper clearance of .040"