Legal Question in Civil Litigation in Oregon

You can sue him, probably in small claims court, where he lives. You can tell the court that he represented that the motor was in working condition but that it actually was not.

Did he deliver the motor to you in Oregon? Then you can sue him in Oregon. But you have to serve the summons and complaint upon him where he lives. He may not show up to court, so you win. You will get a "money judgment" in your favor. Then you file the money judgment in the courts of the state where he lives and try to find his assets to seize. Or you hire a "collections attorney" in the state where he lives to collect on the judgment.