1990 Johnson Evinrude "ES" 40 thru 55, P/N 507872, Page 240Get this manual
1Visual Inspection The first step in determining the condition of battery should be visual inspectionLook for conditions such as damage to the case, loose terminals, evidence of electrolyte seepage, etcThese signs may indicate improper care, installation or application of the batteryLook for excessive corrosion on the battery terminals and cablesCheck the battery cables for worn or frayed insulation Replace cables, if necessaryCheck the electrolyte level in each cellIf electrolyte level is below the plates it is possible the battery is permanently damagedAlso look for dirt, oil or other contaminants floating in the electrolyte r:tl _' LJ
2Hydrometer positive battery cable whenever charging battery