1969 Evinrude Water Pump Replacement

Ok, so I know it's not exactly a classic and probly not even worth fixing but... Well my grandfather left me this boat, a 1969 Evinrude Sweet 16 W/100hp motor, (purchased boat motor and trailor as a package, new) and I spent a lot of summers on it, now that I have kids of my own to take out, I cant deny them the thrill and pleasure of being on the water. I took it to the repair shop because it was overheating and not pumping water, and they quoted me 3 hours @ $85, and $50 for the impellor kit. The kit I can swing but the $255 labor is way out of my range right now.
My question here is, can any of the experts here give me a walk thru on replacing these parts, or direct me to a repair manual (not parts manual) so I can do it myself. I've never worked on a boat moter, but I do have an associates in auto mechanics, so i'm not exactly blind.
Any assistance here would be greatly appreciated...
...thanks Gary

There are not any online manuals that I know of, maybe someone will come along with more information on that.
I would go ahead and get the OEM manual, it will be worth it's weight in gold if you need to repair your engine. The water pump replacement is not hard if you have the manual to help you.