After setting the course record at Spyglass Hill Golf Course on Thursday, Mickelson continued his record setting on Friday. His two-day total of 129 sets a new 36-hole record. Matt Gogel (2001) and Pat Perez (2002) each posted two-round totals of 131, however neither went on to win the title.
Mike Weir matched Mickelson's 67 to move into second place at 11-under-par 133. Paul Goydos and Andrew Magee each carded rounds of 4-under 68. They were joined in a share of third place at 9-under-par 135 by Kevin Sutherland, who posted a 2-under 70.
During the first three rounds, play rotates over three courses - Spyglass Hill Golf Course, Pebble Beach Golf Links and Poppy Hills Golf Course. Pebble Beach will host the final round.
Mickelson, who torched Spyglass Hill for a 62 on Thursday, opened the second round on the 10th tee at Poppy Hills. Lefty got off to a quick start with back-to-back birdies from the 12th to move to minus-12.
The reigning Masters champion rolled in a 6-foot birdie putt at the par-3 15th. Mickelson then sank an 8-footer for birdie at 17 and made it two in a row when he two-putted for birdie at the par-5 18th.
Mickelson, the 1998 winner here, cruised through the front nine with five straight pars. He tripped to his first bogey of the tournament at the par-3 sixth but the 34-year-old closed with a birdie on the par-5 ninth, his last, to move four shots ahead of Weir.
Weir began his round on the first tee at Pebble Beach and he was on fire right from the start. He converted a birdie try at the first to move to minus-7. The Canadian then sank back-to-back birdies from the third.
The 2003 Masters champion jumped to 10 under when he drained a birdie at the par-5 sixth. Weir, however, stumbled to bogeys at eight and nine to slip back to 8 under.
Weir parred the first six holes of the back nine. The seven-time winner on the PGA Tour then flew up the leaderboard to end his round.
He birdied the 16th from 10 feet out and made it two straight when his 10-foot birdie try at the par-3 17th found the bottom of the cup. Weir made it three in a row to end his round as he birdied the par-5 ninth to move to 11 under.
'It was much tougher then yesterday,' Weir said. 'I think playing Pebble Beach, when you are close to the coast, I think the weather affects that golf course more than any. And so, the little bit of wind and rain out there played a big factor on the ball. The course played a little bit longer.'
Kent Jones used a 7-under 65 to jump to 8-under-par 136. He was joined in a tie for sixth place by Greg Owen (69), Charles Howell III (71), Arjun Atwal (68) and Darren Clarke (66).
Olin Browne (65), Jeff Sluman (66) and Arron Oberholser (66) lead a group of 11 players at 7-under-par 137.
Vijay Singh, the World No. 1 and defending champion, posted his second straight 1-over 73 on Friday. He stands at plus-2 in a tie for 129th. He is in danger of missing his first cut since last year's Buick Invitational. If Singh misses the cut, he would be the fourth straight defending champion to do so at this event.