The best way to determine if your engine or gen charges your batteries is to test it with a Volt-Ohm Meter, VOM.
Just because someone says it should doesn't mean it's so.
Check the voltage befor you start your engine, then while the engine is running.
If you see a rise in voltage, around 14.1v- or so, you are charging. If it's the same, no charge is present, but you may not be low, so use some battery power, then start your engine again, check once more.