1975 Evinrude 2HP Model 2502 Full Factory Service Manual, Page 45Get this manual
6-5 GEARCASE PRESSURE TEST To test gearcase sealing, proceed as follows:
1Remove drain plug and screw in pressure test gauge613
See Figure
Stevens Experimental pressure test gauge illustrated
2Pump pressure up to 3-6 poundsGearcase must hold 3-6 powldsIf pressure gauge indicates leakage, submerge gearcase in water to determine source of leakage as eVidenced by bubblesIf gearcase pressure gauge does not indicate eakage, increase pressure to 1618
pounds Pressure shoUld also hold at 16-1 poundsU pressure
does not hold, submerge gearcase in water and check for source of leakageMake necessary repairs and repeat testGearcase must hold within the range of 3-6 pounds and 16-18 pounds pressure
REASSEMBLY AND INSTALLATION OF EXHAUST HOUSING
aIf removed install vibration dampeners