1997 "EU" Johnson Evinrude 5 thru 15 Four Stroke Service Manual, P/N 507262, Page 293Get this manual
Battery Specifications
For each motor, provide one battery that is: 12-volt, heavy-duty, designated "marine" Ventedrefillable or maintenance-free Rated 360 CCA (465 MCA) with 90 minutes reserve or 50 amp-hr
Deep-cycle batteries are suitable IF they meet or exceed the minimum CCA requirements
Installing and Connecting Batteries and Cables Place the battery so it is easily accessible for frequent checking and recharging and in hold-down systemInstall positive cable to positive post and negative cable to negative postWhen connecting to the battery, begin placing largesurface starwasher over the threaded battery post, then stack cables from accessories, then cables from the motorFinish the connection with hex nut, tightened firmly with wrench