Kuchar has made only one bogey through 54 holes at Waialae, and he only came seriously close to one bogey until saving par from a bunker on the par-3 17th.
"I loved the fight", Spieth said.
Keith Mitchell surged into joint third place after making seven birdies in a round of seven-under 63, and joined Chez Reavie on 14 under overall.
"Andrew was tough. He was battling me, took the lead.it was nice to have that pressure, to have come through and to make some birdies coming in".
Kuchar ended a three-year drought by winning the Mayakoba Classic in Mexico last fall.More news: Professional Tennis Players Investigated In Match-Fixing Scandal
Kuchar ran off four birdies in five holes to start his second round on Friday, handled the par 5s at Waialae again and finished with another round 63.
Putnam's birdie at the third and a series of solid pars proved enough to take him into the lead, which he maintained at the turn when he matched Kuchar's birdie at the long ninth. "I wanted to do better on the back nine", said Imahira, whose second round also included a bogey on No. 2. He won the Match Play Championship and the Memorial in 2013.
He never looks to be under stress, though Kuchar says looks can be deceiving. Thanks to a round-opening bogie and a double bogie on the 4th hole, Reavie began the round 3-over and needing a miracle to keep up with leader Matt Kuchar, who posted back-to-back 63s in the tournament's first two rounds. Swafford got off to a slow start but heated up with four birdies in a seven-hole stretch to entertain thoughts of potentially chasing down Kuchar and Putnam. "To win two out of three is insane to comprehend".
Davis Love III (7th): Love III beat the following golfers he 1) is almost 30 years older than and 2) vice captained at the 2018 Ryder Cup in Paris: Bryson DeChambeau, Justin Thomas, Jordan Spieth and Patrick Reed.More news: Iran protests to Poland over Iran-focussed summit
The Sony Open is more about work than play, and he's having just as much fun.
Marc Leishman (T3): It was a great two weeks in Hawaii for Leishman, too.
DIVOTS: Gary Woodland, who didn't shoot worse than 68 last week and still had to settle for runner-up at Kapalua, was among 10 players who missed the 54-hole cut because more than 78 players made it to the weekend.
"Didn't feel as easy as the first two days", Putnam said.More news: Parts of Austria, southern Germany sink deeper into snow