Ryan or whomever ----quick jist here to make sure 100 percent your not leaking gear oil. Just because the reservoir stays full means nothing that the outdrive itself is not leaking. It does not take much to plug and or a small kink in the reservoir line or any oil paths restriction down thru to the outdrive. Not uncommon for this to take place - ( a restriction that keeps the oil level full in the reservoir ).

I would put the outdrive dead level and unscrew the vent screw completely out - does gear oil come out ? if so or if not - stick a thin straw or tie wrap thru the vent hole and see if you get gear oil on it. if not keep bending the straw or tie wrap down ward to see where the oil level is at.

The deal for phantom gear oil leaks a short jist of it ---- is when the prop spins it creates a vacuum, the faster the prop spins the more vacuum force is created - this actually can pull the gear oil out past the prop seal. You can pressure test all day long and will hold pressure 100 percent. . Pressure testing is a good test to perform but is NOT a 100 percent valid test for the phantom gear oil leaks especially without fast prop rotation.

Bravo 3 are more the norm for this exact phantom gear oil leak. actually all drives are but less common than the Bravo 3. That one is extremely common --- the Bravo 3.