Re: Looking for a repair/service manual for a 1983 Evinrude 70HP
If your engine has power trim: the major difference between the two years is the power trim unit. The trim electrical systems are different. The 81 uses a 3 wire motor, the 83 uses the newer two wire motor. Their electrical trim control box internals are different, too. (the 83 has two relays inside.) The 83 uses the newer "plug-in" ignition coils, a minor difference. Some of the plug ends on the ignition system may be different. However, if you can get the manual at a good price, it should cover everything close enough to make it worth your $.