Purchased a boat that has a new Mercruiser Bravo 3 outdrive which was installed in August 2008; the unit had been used for only 2 hours with the new outdrive at the time of purchase. The gear lube container emptied from the point of purchase to my dock, approximately 1 hour. I was told there may be air voids in the line and this was normal. After adding 3 quarts of lube oil, I had the unit pressure and vacuum tested for leaks and the tests indicated the unit was okay. There is no oil in the bilge, and there was no oil in the gimbel housing when the outdrive was removed for testing. Also, there is no sign of oil in the water. I only lose oil while underway. After the test, I am still continuing to lose gear lube. Where is the oil going (through the prop perhaps), and what is the fix?