The American duo combined for seven birdies and two eagles.
"I was teary-eyed when I got the call to play in China, representing my country," Weekley said. "To us it's like the Olympics. It's a dream for me to play in this."
European Tour Rookie of the Year Martin Kaymer teamed with Alex Cejka to put defending champion Germany in second place at 10-under 62, while a group of six teams, including England's Justin Rose and Ian Poulter, the pre-tournament favorites, share third at nine-under 63.
Thursday's round featured the four-ball format which allows each teammate to play his own ball while the low score on each hole is counted.
Friday's round likely will tighten up, as one ball per team can be played on each hole.