1995 Johnson/Evinrude Outboards 50 thru 70 3-cylinder Service Manual, Page 234Get 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 (50 amp-hrs)
Deep-cycle batteries are suitable IF they meet or exceed the minimum CCA requirementsInstalling 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 post
rn When connecting overthe battery, begin by placing largeto the threaded battery post, then stack surface star washer