1992 Johnson Evinrude "EN" Electric Outboards Service Manual, P/N 508140, Page 20Get this manual
Battery Care Keep the battery charged at all timesCheck the state of charge by making specific gravity readings with battery hydrometerIt is suggested that specific gravity readings and checking for loss of water be made every two weeksIf the battery has been standing for 30 days, recharge the battery before putting it into service to ensure reliable starting Charge battery to the specific gravity recommended by the battery manufacturerCheck the specific gravity of the battery electrolyte with battery hydrometer, preferably one that has built-in thermometer and correction chartNo other method should be used to determine the charge condition of batteryNote also that hydrometer reading is not accurate if water has been recently addedbecause he water has not had chance to mix with the electrolyteThe proper water level should be maintained at all times If water is added in freezing weather, the battery should be charged to ull charge at onceOnly pure distilled water or water approved for battery use should be added to the battery to replace water lost through evaporationNever add acid except when acid has been lost by spillingInstall the battery near the motorMount the battery in ventilated case and attach the case to the boatA loose battery may shift in the boat, damaging itself or other equipmentTighten holddown nuts evenly until the battery is secureIf hold-down nuts are too tight, distortion and damage to the battery case will resultConnect battery cables, making sure clamps are tight on battery posts to ensure good contactApply coat of petroleum jelly to exposed areas of the battery posts and clamp connectors to retard corrosion Battery Cable Extension