I have an extra lower unit for my 1979 15 hp Evinrude. I am using the drive shaft and shift rod. I am going to keep it for parts and want to know how to store it. Should I keep oil in it and keep it up right? Should I buy a threaded rod to put where the shift rod goes so I can keep everything in place. What about the opening for the drive shaft? Should I drain it or is that bad for the seals? My plan was to insert a threaded rod where the shifter goes and leave oil in it and keep it upright. Any advise would be great. Thanks.