Re: 1963 Satrcraft Gale IIII?
Many of the commonly-needed parts are the same as the same period's 40hp models of Johnson and Evinrude. Stuff like coils, etc.
You can find common parts listed under Gale in the Sierra Marine parts catalog at any NAPA Auto Parts Place. They have things like points, plugs, impellers, carb kits, and the like.
If you can find the model number on your Gale, we can give you some more information on the engine, but you'll find that it's much the same as the 35 and 40 hp Big Twins from the late 50s and early 60s. There are some differences, but most commonly replaceable parts are the same.
Gale part numbers are the same as OMC part numbers, so many other parts can be obtained at your nearest Evinrude dealer. Just don't tell them you have a Gale.
As for service and parts manuals, I don't have a source, but I have seen them on ebay.