Do you have access to a hand-operated gearcase pressure tester, OR a Mighty-Vac?

If so, disconnect the black line from the Crankcase Pressure Check Valve, and pressurize the hose to 6 psi. Watch to make sure it HOLDS the pressure.

If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!