1975 Johnson 4HP 4R75, 4W75 Outboards Service Manual, Page 45Get this manual
bUsing new gasket, secure iriller exhaust housing and lower motor cover to power head with the six attaching screwsInstall water tubecPlace new gasket on the exhaust housingApply oil or liquid soap to end of water tubeAssemble power head to exhaust hOUSing, and torque attaching screws to specifications outlined in Section 2dCoat driveshaft splines with mixture of one part molybdenum sulfide to forty parts OMC SeaLube Anti-Corrosion Lube (measured by volume)Do not coat top surface of shaft as lubricant here may prevent seating of driveshaft in crankshafteInstall gearcase on exhaust housing making sure water tube enters grommet of water pumpfInstall leaf plate assembly, intake manifold, and carburetor as described in Section 35