1994 Yamaha Century lower unit help

Hi, I have a 1994 Yamaha Century 21ft. Yesterday the lower unit went out on it. Does anyone here have a repair manual or know where I can get one or has experienced rebuilding a yamaha lower unit or even were I can get parts for it at? I was told Yamaha only made this boat for two years...it has a yamaha 5.7 motor (looks like a car engine) in it and the lower unit was built by yamaha too..any help would be greatly appreciated. up until yesterday the boat ran perfect..
chuck

[boats.net]

Here is the link to parts list http://www.boats.net/parts/search/Ya...e/0/parts.html
Most of the parts are no longer available.