I have a Hustler 42" ZTR with a 17HP Kohler. I recently noticed that the mower would barely turn over if I waited 6 or 7 days between cuts. I figured that it was the battery, so I had a new battery installed. The same thing is happening. If I wait more than a couple of days without starting it, it will barely turn over. What could be draining my battery when the mower is not in use? Thanks!