The Canadian lefthander's two-day total of 12-under 130 tied the Riviera Country Club record set by Davis Love III.
Five days after ending a nine-year victory drought, John Daly is another shot back after a 64.
Players who hit the course in the morning escaped threatening skies, but there was the sound of thunder and some rain in the afternoon.
Tiger Woods fought his way back into contention with a 66 and at 4-under is assured of making his 117th consecutive cut.
Stuart Appleby birdied six of his nine final holes to finish a 64. He is four shots back at 8-under 134.
First round co-leader Shigeki Maruyama dropped into a tie with Appleby through seven holes after opening with three birdies and a double-bogey.
Swim Week Miami Beach 2014 [PHOTOS]