1981 Johnson/Evinrude 4HP Outboards Service Manual, Page 66Get this manual
INSTALLATION OF STANDARD GEARCASE aIf powerhead has not been removedremove powerhead screws See Figure 6-29Lift powerhead from exhaust housing Remove set screw retaining bellcrank and shift leverSee Figure 6-21Pull shift lever outward just far enough to release bellcrank and remove shift rod and bellcrank assembly from exhaust housingc Install shift rod and bellcrank into the shift rod bushing in gearcaseCheck for function by pushing down on the shift rod Propeller shaft should be in neutralPull upward on shift rod and propeller shaft should be in gear dInstall gearcase with shift rodguiding water tube into water pump grommetSee Figure 629a
GEARCASE PRESSURE TEST To test gearcase sealingproceed as followsaRemove drain plug and screw in pressure test gaugeSee Figure 6-30 Stevens Experimental pressure test gauge illustrated Pump pressure up to 3-6 pounds (21-42 kPa) If pressure gauge indicates leakage, submerge gearcase in water to determine source of leakage as evidenced by bubbles If gearcase pressure gauge does not indicate leakageincrease pressure to 16-18 psi (110-124 kPa) If pressure does not holdsubmerge gearcase in water and check for source of leakage Make necessary repai rs and repeat testc Screw in vacuum testerPump out to 3"-5of mercury and see if vacuum holdsThen pump out to 15" of mercury and check If gearcase fails to hold on either test, put oil around suspected sealIf leak then stops or oil is drawn inthat seal is defectiveWhen gearcase checks out OKrefill with lubricantSee Section Lubrication ChartCOA3004