Chrysler 20 and 30 HP Outboard Motors Service Manual OB 3435, Page 103Get this manual
The hydrometer test should be performed firstIf specific gravity indicates less than 1.225, the battery must be charged before further testing can be done battery which does not accept charge is defective and no further testing is required HYDROMETER
DISREGARD CURVATURE
t-1'""1'- EYE LEVEL
Hydrometer TestPrior to testing, inspect the battery for any damage (broken container, cover, loose post, etc that would make the battery unserviceableTo read the hydrometer correctlyposition the top surface of the electrolyte in the hydrometer at eye levelFigure 4Disregard the curvature of the liquid where the surface rises against the float due to surface tension Draw in only enough electrolyte to keep the float off the bottom of the hydrometer barrel with the bulb releasedThe hydrometer must be kept in vertical position while drawing in liquid and taking the reading
CAUTION
Care should be taken when inserting the tip of the hydrometer into the cell to avoid damage to separators Broken separators could result in premature battery failureHydrometer floats are generally calibrated to read correctly at 80 FWhen taking reading at any other temperature, correction factor must be used The correction factor is approximately 0.004 specific gravity, referred to as points of gravityFor each 10 below 80 F, subtract pointsAlways correct the readings for temperature variationTest the specific gravity of the electrolyte in each battery cellFigure 4Reading Specific Gravity with Float- Type Hydrometer