Where can I find a manual for a Poulan Weedeater, 12.5 HP, 38" riding mower? The Poulan site doesn't show it, and the customer service doesn't recognize what I am talking about.

You will need your model and serial number before you start User Manuals (http://www.poulanpro.com/node7975.aspx)

There should be a tag under the seat with the numbers you need .
Probably built by electrolux or Ayp.
Luck