not a problem, you want the ammeter to indicate a 'neutral' condition, the battery is charged and the generator is keeping up with demand, what the ammeter is telling you is the amount of current being sent to [drawn by] the battery ... what should happen is the ammeter drops minus while you're cranking the engine, once started, it should move back to neutral, fast or slow depending on how long it cranked - might take a jump up to plus at first and fall back to neutral, all good
Bill