1971 Johnson 40HP outboards Service Manual, Page 43Get this manual
DISASSEMBL OF POWER HEAD aRemove lift bracket, cylinder head and cylinder head gasketRemove by-pass covers and gaskets, and inner and outer exhaust covers and gasketsSee Figure 5-6
If pitting exists on the inner exhaust plate,
be certain to install new plate upon reassembly
bLoosen clamps and remove oil return hose from crankcasecDrive out taper pins from back to front of crankcaseSee Figure 5-7Remove eight small and six large screws attaching crankcase to cylinder blockSee Figure 5-8Tap top side of crankshaft with rawhide mallet to break seal between crankcase and cylinderLift crankcase from cylinder blockFigure 5-8Crankcase Screw Locations dRemove oil drain valve from crankcase for cleaning and inspectionSee Figure 5-8