I would go for an older OMC 15. Bulletproof and easy to repair when they do have trouble. I know they don't have all the whistles and bells of the new ones BUT SO What? Fuel economy, noise and pollution. I would rather set points than have to order a CDI box. In my boat box I have a flywheel puller, points, water pump impeller and a temp gun. The flywheel puller can also be used as a wad knocker(right Paul?). Good luck, too bad you don't live closer, I have several that are going together one at a time and out the door, none right now though
I am with tom... except I just like the newer ignition. CDI all the way!!! Anything from the mid 80s on, depending on what money affords you. I have a 1993 mercury 15 that is by far the best running motor out of my fleet, so take that for what it's worth as well. I have an OMC 60 on my big boat and an omc 30 on the pontoon as well, and all of them are great. Condition and maintenance are key.
I never had ANY issues with my E-tec.