I just bought a used 1650 that's in pretty decent shape. in the future, I'm sure I'll have many questions, but one popped up the first time I mowed with it this weekend: While mowing, the ammeter shows a current drain. I assume this is due to the magnetic clutch, but my 1610 doesn't show this. The 1650 battery drained pretty good over an hour long period. Any clues? I don't think this is normal.