The title is "Johnson/Evinrude Outboards, 1971-89 repair Manual" by Seloc Publications (www.selocmarine.com).
Unfortunately you'll find a lot of information on other outboards you don't care of, but that's all you can find. I bought it few years ago and I'm quite happy.
Send me a private message and I may help you on specific topics - if you are not in a hurry.
I take the opportunity to ask another question: where on the net can I find spares for the same engine? In particular the cooling water impeller.