Mercury 200XL Verado Gearcase Pressure Test
Any time you remove the lower unit from your outboard for repairs, it gives you the perfect opportunity to perform a gearcase pressure test. This test tells you whether the lower unit is capable of holding in oil under pressure and/or preventing water from entering the gearcase.
Watch the video above and follow the steps below to learn how to do a gearcase pressure test on a Mercury 200 outboard.
NOTE: We pressure tested the lower unit on a Mercury 200XL Verado, but the method is the same or similar for virtually all outboard makes and models.
Tools and Supplies – Mercury 200 Verado Gearcase Pressure Test
How to Pressure Test a Mercury 200 Lower Unit
Step 1. Drain the oil out from the lower unit.
Step 2. Remove the lower unit vent screw and attach a gearcase pressure tester.
Step 3. Using the tester, increase the pressure within the lower unit to 12 PSI, and let it sit for about 2 minutes. If the lower unit is properly sealed, the pressure will remain constant. However, the pressure will drop if there’s a leak somewhere.
Step 4. Release the pressure, then remove the pressure tester and reinstall the lower unit vent screw.
Step 5. Refill the lower unit with gearcase oil and you’re done.
Speaking of 200XL Mercury Verado gearcase oil, watch the video below to learn how to change the lower unit oil in a Mercury 200 outboard.