Jason Dufner and Terry Hatch share fourth place at 9-under-par 135. Fran Quinn and Bubba Watson are two strokes further back at minus-7.
Couch, who was one of four first round co-leaders, opened on the back nine with three consecutive pars. He got going with a short birdie putt on the par-4 13th. He came back to birdie the 16th from 15 feet out before closing his first nine with a birdie at the 18th.
On the front side, Couch jumped well out in front before stumbling down the stretch. The 2001 Florida Classic winner moved to minus-10 with a birdie at the first. He continued his strong play with a birdie at the third.
Couch then climbed to 12-under with a birdie at the par-5 fifth. However, he stumbled into the clubhouse. He three-putted for bogey at the sixth and a poor chip shot led to another bogey at the eighth to fall back into a share of the lead.
'It was brutal out there,' said Couch of the windy conditions. 'I think we had the tough end of the draw. It was tough Thursday afternoon and then it was blowing about 30 m.p.h. this morning. I'm just happy to be playing on the weekend.'
Wurtz, who opened two shots off the pace, fell further back with a bogey at the par-4 10th, his first hole. However, he closed that side in excellent fashion. He rolled in back-to-back birdies from the 15th then dropped in another birdie on 18 to make the turn at minus-6.
Around the turn, the 1997 Shreveport Open winner birdied the second and fourth to move to 8-under. He jumped into a share of the lead as he sank a five-foot eagle putt at the fifth.
'Today is the best I've putted all year long,' said Wurtz, who needed just 23 putts during Friday's round. 'I have more confidence on faster greens. I was just fortunate the ball was going in the hole.'
Bohn also opened on the back nine. He birdied the 11th before matching Wurtz' consecutive birdies from the 15th. On the front side, Bohn sank a birdie try at the second and followed with another at the next. He capped his round with a birdie at the fifth.
'I played real well today,' said Bohn, who carded a 58 in the 2001 Bayer Championship on the Canadian Tour. 'I believe a little bit of luck was on my side today too. It was definitely a challenge out there.'
The cut line fell at even-par 144 with 79 players moving on to play the final two days. The 79 is one shy of the most players to ever make a cut on the Nationwide Tour. Eighty players advanced to the final two rounds at the 2001 Boise Open. Nick Cassini and Bobby Gage, the runner-ups the last two weeks, survived on the number.