Mercury Electric Outboards 222 Thruster Service Manual, Page 10Get this manual
ELECTROLYTE LEVEL Check electrolyte level in battery regularlyA battery, in use in hot weather, should be checked more frequently because of more rapid loss of waterIf electrolyte level is found to be low, then colorless, odorless drinking or distilled water should be added to each cell until liquid level rises approx316" (4.8mm) over plateDO NOT OVERFILL, because this will cause loss of electrolyte and result in poor performance, short life and excessive corrosion
To ensure good electrical contact, cables should be clean and tightIf cable terminals are corroded, cables should be disconnected and terminals cleaned separately with soda solution and wire brushAfter cleaning and installing clamps, apply thin coating of petroleum jelly on cable clamps to retard corrosion
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