This OMC Upper Outdrive has only been used in fresh water and can easily be rebuilt by replacing the upper gear as shown in the picture.  The gear has some chipped teeth and requires replacement.  This outdrive is being sold as-is with no warranty  ,Once rebuilt it promises to deliver an efficient and reliable performance. The manufacturer part number is 985685, ensuring that you get the right fit for your 4.3L boat.  Replacement parts for this outdrive are widely available.