I'm going to ask for some help from the collective, but with a preface that it's not my boat and I might not have all the info. My father in law has a 1998 270 DA, single 7.4 L mated to a Bravo III. It has a leak in the transom assembly; he's electing not to fix that for now. The bilge pumps can keep up - except that there is also some type of oil leak that stops the pumps. If there is any oil at all in the bilge is keeps the pumps from activating. The issue is no one can seem to figure out the source of the oil leak. He thinks it looks like some type of hydraulic fluid (he would know - after years in the hydraulic value business). The mechanic has been all through the boat and can't seem to find anything. He focused on the drive - raising and lowering the drive and running the engine. He also checked the power steering for leaks and the hydraulic trim tab system. With nothing found the plan for now is the splash the boat and see if for some reason the oil leak occurs only when in the water. I don't know if any systems were low on oil / fluid. So my admittedly broad question is - are there any systems known to leak oil / fluid? What should my FIL look at to try to find and fix the oil leak? This problem drove him bonkers last season and I want to help him.