My battery does not charge when I use my Troy Bilt 2146 Yard Tractor. Someone suggested the problem could be the 'stator' or 'regulator'. Neither item is in the parts list. Are they part of the alternator or solenoid?

I am not familiar with your model, but some alternators have a built in regulator. This is a common problem with these tractors and usually indicates a need for a new alternator. When the tractor is running you should have 14 volts or at least 13.6 volts. If not, replace the alternator. You should replace the battery also because a bad alternator is caused by a bad battery and vice versa. DrTom4444