trapped water in '93 OMC Cobra drive
 

When I removed the drive from the transom to replace a cable it
drained a lot of water as soon as the gasket seal broke at the
transom. The water leaked from a drain hole on the starboard side of
the horizontal fin. So is a vacuum being created by a plugged air
breather somewhere? The water should drain out after each use since it
has a hole for it to drain out of.
Thanks for any help,
Steve