I have an XDP B Volvo outdrive in my 28' Fourwinns with a 5.7 EFI engine. What might cause water to leak in only when the outdrive is down.
Are you noticing the water after running the boat and so saying it leaks only with the drive down? If that's the case it may be a leak from a raw water hose so check out your cooling system plumbing while the engine is running. ( Use a flashlight and be careful)
The obvious answer is of course the U-joiint bellows gasket. But typically these would tend to either leak all the time, or leak when the drive is up--since when up the corrugated bellows is extended. But check that as well, plus your shift bellows and the transom seal.
Another possibility. The rubrail at the transom of many boats--this covers the hull-to-deck joint, where the deck and hull are screwed together. Aboard many boats with integral swim platforms, this is carried low to the water aft. It could be leaking and could be caused only when the drive is in a given position, since the trim rams and the drive are pressing on the transom differently at different angles of trim.
In any case, you gotta get back there and look.
Thanks Kevin. It leaks even when sitting without the motor running or had just been running. Think I'll need to get a little camera under there.
Hey Chris check all your hose clamps,and while you are there check all of the engines drain plugs,and the "frost plugs" look for RUST around them and for some kind of "GREEN" thats a sign that they are starting to leak, on the drain plugs sometimes the rubber "O" ring will leak and it will do it only when the engine is hot and running because of the pressure from the water pumps and temperature, good luck :-)