There are Clymers and Seloc both have "manuals" which cover this vintage Merc. They are somewhere between an owners manual and a shop manual--usually enough to do the routine and replacement maintance. This vintage motor is fairly simple to work on, and you should have no problems, short of a complete rebuild--then you may want to send it off. I had a 1986 25 hp Merc and it was a good work horse. I put over 1000 hours on it and it was still going strong when I sold it.