Re: 1973 50hp rude made for salt water?
Although there is plenty of disagreement on the various boating forums as to which company came out with the idea of "saltwater "outboards, there have been a few models that claim to be exactly that.
Depending on who you want to believe, the differences relate to better paint and greater use of stainless steel parts. To the best of my knowledge, OMC has been using all stainless fasteners for a very long time. I believe that they have also been using stainless driveshafts and propshafts too. Supposedly, one of the main differences in the "saltwater" OMCs is that they have stainless tilt tubes in them.
Other than these items, however, there isn't any substantial difference between a "saltwater" outboard and a regular outboard. As I mentioned before, I don't think OMC had a "saltwater" engine in 1973 (I think they came up with the idea in the 90s), so your motor is the same as any other OMC 50hp motor of that year. As TD mentioned, if your were to start using your motor in a salt water environment, it would be advisable to pay closer attention to lubrication schedules, etc.
That said, keeping your motor lubed, no matter what type of water you use it in, is always a good idea. Its cheap maintenance and eliminates a lot of headaches.
