Re: Pulling a Bravo3 off.
The seal for the input shaft keeps oil in but is not designed to keep water out (maybe it should be!) so that is certainly possible. At the least he should have been cracking the drain plug to see if he got water out before gear oil. If you want a low maintenance marine power source you should not bother with sterndrives. Outboards, while they are very complex in the power head area, are definitely less work in the drivetrain area. No u-joints, bellows, gimble, etc. If you buy one new and run it 10 years, your maintenance will be much less than an I/O. But the eventual repairs can cost even more due to parts prices and complexity.