You might want to do the test as described in the manual.
Completely drain all oil first.
Pressure Test
1 Attach pressure tester to oil level hole.
2 Pressurize sterndrive to 3-5 PSI.
3 Rotate propeller shaft and u-joint shaft to check
sealing. Wiggle,push,pull and do the shifter to.
4 If pressure loss is indicated, use a soapy water
solution to find source of leak. Make necessary
repairs then repeat test.
5 If pressure loss is not indicated, increase
pressure to 16-18 PSI.
6 If pressure loss is indicated, use a soapy water
solution to find source of leak. Make necessary
repairs then repeat test.
7 Drive must not lose more than 1 PSI in
3 minutes.
8 Drive must pass pressure test before making
vacuum test.
Vacuum Test
1 Attach vacuum tester to
the oil level hole.
2 Pull vacuum to 3-5 inches of mercury.
3 Rotate propeller and U-joint shaft to check
sealing. Don't forget the shifter.
4 If drive does not hold vacuum, apply gear oil to
seal surfaces to find source of leak. Make
necessary repairs then repeat test. No loss of
vacuum should occur on low vacuum test.
5 If vacuum loss is not indicated, increase vacuum
to 14-16 inches of mercury.
6 Rotate propeller and u-joint shaft to check
sealing.
7 If drive does not hold vacuum, apply gear oil to
seal surfaces to find source of leak. Make
necessary repairs then repeat test.
8 Drive must not lose more than 1 inch of mercury in 3 minutes
Yes, drive off of boat. Kind of hard to rotate input shaft when still on boat.
