That gave the 24-year-old Perth native, starting his rookie year with a European Tour card, a one-stroke advantage over a trio of players in second place that includes Sergio Garcia.
Kulacz shot 11 birdies and two bogeys and fell one shot short of equaling the Abu Dhabi Golf Club course record set by the Swedish Ryder Cup player Henrik Stenson four years ago.
Kulacz played late on the second day after a strong lunchtime breeze that had been blowing in off the Arabian Gulf subsided.
The late calm confirmed the view of Garcia, who also played in mild early morning conditions, that the shifting local weather could have an impact on who eventually wins the $390,000 winner's check.
Garcia who shot a 67 said it was no coincidence that he, Ireland?s Shane Lowry and Sweden’s Peter Hanson, who all reached 11 under, did so after receiving early morning start times.
Players blown into the thick rough at the Abu Dhabi Golf Club by the wind were also trying to cope with new clubs that comply with the recent groove regulation changes of both the European and PGA Tours.
“The weather really helped me because in the morning it was pretty calm. And playing on firm greens it is pretty hard getting fliers out of the rough with new grooves.”
Garcia still feels pain from a right hand injury sustained at the Dubai World Championship in November and receives daily ultrasound treatment.
“With the hand problem and bad weather at home I have not been able to practice as much as I would have liked, so getting into the lead has exceeded my expectations here,” said the Spaniard before Kulacz overtook him at the top of the leaderboard.
“I feel I have played nicely but there were shots where I could have been a bit more positive. But when you have been unable to practice as much as you want doubts do creep in.”
The injury did not prevent Garcia from making six birdies and only one bogey in his round, while Lowry had seven birdies in his.
Until Kulacz made his late run playing in the second last group of the day, Lowry was enjoying his first appearance at the top of a European leaderboard since turning professional after his victory, as an amateur, in the Irish Open last May.
The highest-profile victim of the windy conditions – and the new groove regulations – was England?s Lee Westwood, who on his last visit to the Arabian desert won the Dubai World Championship to reach the No. 4 ranking.
He missed the cut after shooting a 78 for 3 over and complained about having to start the year using new clubs.
“What a time to have to change your clubs when you are playing your best golf ,” he said. “I need to do some work with my irons. I don?t know whether they have put the wrong shafts in them or whatever. They just don?t feel right, they don?t feel the same. They feel like fishing rods.”
One of the three first-round leaders, England’s Ian Poulter, was unable to repeat his 7 under start. He had a round of 70 and was three shots off the lead.
Italy’s Francesco Molinari had a hole-in-one at the 174-yard fourth hole with his 7-iron tee shot.