1985 Mercury Outboard V-300 V-3.4L Shop Service Manual, Page 34Get this manual
lOor (3.3 C) above BOor, add specific gravit po int (.004) to ydrometer readingExa mple: hydro meter reading of 1.260 at ll or (43 C) would be 1.272 corrected to BOofindicating full charged batteryf or every 10 below BOorsubtract points (.004) from the readingExampleydrometer reading of 1.272 at OO (- IB C) would be 1.240 corrected to BOor indicating par tially charged batter y SPECIFIC GRAVITY CELL COMPARISON TEST
Th is test may be used wh en an instrumental tester is not ava il ableTo perform th is test, measure speci fi gravit of each cellregardless of stat of charge, and int erpret res ults as followsspecifi gravit read ings show differe nce bet ween ighest and lowest cell of .050 (50 poin ts) or mo reba tt ery is defecti ve and shou ld be replaced
Electrolyte Level
Check electrolyte level in batt ery regularl yA ba tt ery in use in hot weather should he checked more fr equ entl because of more rapid loss of water If electro lyte level is fou nd to he low, then colorlessodorless drinking or di stilled water should be added to each cell until liquid level rises approx3 16" (4.8mmove plateDO NOT OVERFILL, becau se this will cause loss of electrolyte and result in poor perform ance, short life and ex cessive corrosion