Ok, Really stupid question...a friend of my gave me an older Johnson 3hp motor. It ran for about 5 min then stopped. I would like to get a repair manual, even found a web page that might have one, I just don't know the year of this engine, neither does the person who gave it to me. How can I find out? 
Where would the Serial number be? Any help would be nice. Thanks.
Where would the Serial number be? Any help would be nice. Thanks. 