1993 Johnson Evinrude "ET" 60 thru 70 Service Manual, P/N 508284, Page 227Get this manual
Battery Specifications All batteries should be of heavy duty, marine constructionMaintenance-free or sealed batteries are acceptable for use ONLY with engines that are equipped with fully regulated charging systemRefer to Specifications, Section 1Deep-cycle batteries must not be used as the engine's cranking batteryA battery that is not fully charged or less than recommended capacity may not crank the engine fast enough to produce ignition component outputFor best performance, OMC recommends you use 12-volt battery with minimum rating of 360 amps cold cranking (eeA) at (72 amphrsat -18 e) and 115 minutes reserve capacity rating at 80 (27 e)Battery Testing