Chez Reavie (65) and Stewart Cink (62) were four behind.
Kuchar has been one of the steadiest golfers on the tour this season and said the key for him is keeping the ball in play and limiting his mistakes.
On the par-4 fifth, Putnam's 155 yard approach to 9 feet set himself up for the birdie on the hole.
"I anticipate needing another good score tomorrow", Kuchar said. 18, 1-3) with three of those birdie makes coming from outside of 12 feet.
The Australian shot a two-under 68 third round to get to 11-under at Waialae Country Club in Honolulu on Saturday. The veteran continued to limit mistakes (he's carded just one bogey in 54 holes and missed only two greens in regulation in Round 3) and turned in a bogey-free, 4-under 66.
Matt Kuchar shot a 66 to add to his scores of 63-63, gaining a two stroke advantage over Andrew Putnam, who made 67. But he had a good session with his swing coach in Dallas, and it paid off two weeks later on the Gulf side of the Mexican coast.
"I loved the fight", Spieth said. "It's always a surprise when I it disappears".
"Honestly, I didn't think about it at all until after the third one went in", Reavie added. For now, he has to figure out how to make up four shots on Kuchar. Marc Leishman (64) and Ted Potter Jr. He went one lower at the Sony Open at 18-under 192. He likes it better when he can play a few tournaments. Teryn Schaefer presents the best social media posts from around the world of golf in "Good, Bad & Unusual" and after each day's play brings you the biggest talking points in "The Takeaway".
Clearly, the 40-year-old is in a better spot than when he had gone more than three years without winning and was left off the Ryder Cup team for the first time in 10 years.
Kuchar has also been in fine form after ending a three-year title drought by winning the Mayakoba Classic in Mexico late last year. He felt as though he was grinding too hard, and that's not a trait he wears well.