I was recently given a jon boat with a Merc 200 motor (I assume it is a 20 HP but I know very little about boat motors). The serial # is 2433082 which I assume dates it in the 70's. I would like to purchase a tech manual or whatever I would need that would have capacities, etc. so a friend can help me get the engine running smoothly. Can someone tell me where I can order this manual? Does it have to be specific to my motor or will it cover numerous years/models like some Chilton car manuals (am I mixing up repair and tech manuals?). Any assistance would be greatly appreciated.