Re: mercury 150 hp recharging
Assume you've checked the water in your battery? Fully charged battery should measure 12.65 volts (at 80ºF, varies slightly with temp). Hydrometer, $10 at autozone, let's you check each cell to see if one is weak. Wait a few hours after charging to allow "surface charge" to dissipate.
Test of the charging system: measure the battery voltage with the engine running, should be a volt or so higher than battery open circuit voltage at idle...to upwards of 14 at WOT (depending on the motor). Charging system output low, most likely suspect = rectifier...might as well inspect the wiring for corrosion first.
