1975 Johnson 4HP 4R75, 4W75 Outboards Service Repair Manual P/N JM-7503, Page 50Get this manual
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REASSEMBLY OF GEARCASE
Figure 6-9AGearcase Pressure Test GEARCASE PRESSURE TEST To test gearcase sealing, proceed as follows: 1 Remove drain plug and screw in pressure test gaugeSee Figur