1996 Johnson Evinrude "ED" 9.9 thru 30 2-Cylinder Service Manual, P/N 507122, 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 (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
When connecting to the battery, begin by placing largesurface star washer over the threaded battery post, then stack cables from accessories, then cables from the motorFinish the connection with hex nut, tightened firmly with wrench