1991 Johnson/Evinrude EI 60 thru 70 outboards Service Manual, Page 230Get this manual
Battery Specifications All batteries should be of heavy duty, marine constructionThe battery must be vented, refillable typeA battery that is not fully charged or less than recommended capacity may not crank the engine fast enough to produce ignition component output60 thru 70 For 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 (2JO e)Battery Testing