Craig Stadler fired a 6-under 65 and is tied for second place with John Harris, who carded a 5-under 66. The pair finished 36 holes at 6-under-par 136.
Two-time U.S. Open champion Curtis Strange was closest to Wadkins most of the second round, but a triple bogey-8 on the 17th dropped him down the leaderboard. He shot an even-par 71 and is tied for fourth place with three-time winner and leading money winner, Loren Roberts, who posted a 3-under 68. The pair is knotted at minus-5.
Wadkins established a new course record on Friday with a 9-under-par 62, but he started slowly on Saturday. He parred his first five holes, then collected his first bogey of the tournament at the sixth.
Wadkins took advantage of the par-5 seventh. He knocked his third to 2 feet and kicked in the short birdie try. Wadkins made it two in a row at the eighth when his 30-footer found the bottom of the cup.
He dropped another shot at the par-5 11th after he badly hooked his drive. Wadkins parred his next three until he hit a mammoth drive at the par-4 15th. He skipped his second to 8 feet and converted the birdie opportunity.
Wadkins bogeyed the 16th, when his 5-iron tee ball missed the green, but his slip down the leaderboard hardly mattered. His closest competitors made a mess of the par-5 17th hole, starting first with Stadler.
Stadler, who has not won on tour since 2004, recorded eight birdies over his first 16 holes. He even let some slip away as he had only 5 feet for eagle at the seventh, but missed.
Stadler found water at the 17th and eventually double bogeyed the hole.
'I hit a lot of good shots,' acknowledged Stadler. 'Yesterday, I didn't think anyone could have shot 62, but today I could have very easily - without butchering 17.'
Strange got within one of the lead when he reached 17. The 1998-89 U.S. Open winner dumped two balls in the water at the hole en route to a triple bogey-8.
Wadkins parred out and is in position to collect his second win on the Champions Tour. He captured the 2001 Lightpath Long Island Classic, his first event on the elder circuit.
Mike McCullough shot an even-par 71 and is alone in sixth place at 4-under-par 138.
Tom Watson, D.A. Weibring and Bruce Summerhays all shot matching rounds of 4-under 67 on Saturday. They were joined by Scott Simpson and Wayne Levi, who both posted 70s, in seventh place at 3-under-par 139.