Paul Gow, David Hearn, Scott Gump and Mike Sposa tied for third place at 7-under-par 137. David McKenzie and Scott Petersen were one shot further back at 6-under-par 138.
Schultz started on the back side at Shadow Hills Country Club and found trouble early with a bogey at the par-3 12th. Schultz was able to counter quickly and picked up a birdie at the par-4 13th to get back to minus-7.
'The way I played on the front nine and to be even-par felt like I stole something,' said Schultz. 'I feel guilty. This course is not fun if you're playing from the rough.'
The 31-year-old ran off a string of pars around the turn until he tallied another birdie at the par-5 fifth.
Schultz, whose best finish on the Nationwide Tour this season was a tie for sixth at the Pete Dye West Virginia Classic, added a birdie at the par-5 ninth, his last, to maintain the lead heading into the weekend.
'It was raining, cold and windy,' Schultz said. 'That is as uncomfortable as I've felt in a long time. Today wears you out while yesterday came pretty easy.'
Long made an early run with three consecutive birdies starting at the par-4 third to climb to 5 under. He then birdied the par-3 eighth, but stumbled to a bogey at the ninth.
The New Zealander put together a strong finish with a birdie at the par-5 15th and back-to-back birdies from the 17th to close out his round.
'It was a good day for me,' said Long. 'I wasn't that far away yesterday. I got away with a 70 yesterday which gave me some momentum today.'
Casey Martin shot a 68 to move into a tie for ninth place at 5-under-par 139 along with Scott Gutschewski, Brad Elder, Tim Conley, Richard Massey and Tim Simpson.
The halfway cut came at even-par 144 with 66 players surviving for the final two rounds.