1993 Johnson Evinrude "ET" 90 degrees CV Service Manual, P/N 508285, Page 208Get this manual
1301 31Before installing lubricant, pressure test and vacuum test the gearcase as follows: Remove the oil level plug, and screw in pressure test gauge Pump up pressure to 3-6 PSI (21-42 kPa)If pressure gauge indicates leakage, submerge the gearcase in water to determine source of leakage as evidenced by bubblesIf the gearcase pressure gauge does not indicate leakage, increase pressure to 16-18 PSI (110-124 kPa)If pressure does not hold, submerge the gearcase in water and check for source of leakageMake necessary repairs and repeat test Screw in vacuum testerPump outto 3-5 in (76-127 mm) of mercury and see if vacuum holdsThen, pump out to 15 in(381 mm) of mercury and checkIf the gearcase fails to hold on either test, put oil around suspected sealIf leak then stops or oil is drawn inthat seal is defectiveWhen the gearcase checks OK, refill with the proper lubricant !] 32Fill the gearcase with lubricant as follows :