Re: 1969 Evinrude 85 hp won't shut off.
First. Don't disconect the battery when the engine is running! <br /><br />I think this goes for all boat motors in general with full electrical systems, but especially ones with early electronic ignition. In your case, that ignition amplifier module is almost $400 to replace. I know, because I've got the same motor as you, although I haven't had it very long. <br /><br />Regarding your shutdown problem. Get a good manual that shows the wiring diagram for your year and make of motor. You'll be totally lost without it.<br /><br />Start you troubleshooting at something called a "blocking" diode. I beleive it has two purposes. One, to pass electical current from the battery to the neutral shift solinoid during engine starting, and two, to prevent the engine from running when the ignition key is turned off. If this diode has become shorted, is will allow electrical current that nomally goes straight to the shift solinoids to pass back into the ignition system.<br /><br />You may also have some shorted wires in the harness somewhere causing the same problem. Do a really good visual inspection on all of the electical wiring starting at the engine and working you way up to the control box and ignition switch panel. Because you have hydroelectric shift, the wiring surounding the control box and the ignition key are especially important.<br /><br />From my limited experience with my own 1969 85hp Johnson, this is where I'd start.<br /><br /> Good luck.
) Been checking the wiring, even the key switch most of this holiday, had no idea to check or replace the diode. I have several of these motors desembled for parts. <br />Thank you gardian452 for this info which is appreciated.