Bidding to land the title for a first time, Torphins Golf Club-attached Hutcheon carded eight birdies in total in the penultimate circuit as he moved to 16-under-par following a 65 on the Lansdowne Course.
O’Hara, the 2017 winner, is his nearest challenger, sitting two shots behind after a 69, with another former champion, Irishman David Higgins, two further back in third spot following a 68.
Hutcheon, a three-time Scottish PGA champion, had started the day four shots behind the halfway leader, Welshman Toby Hunt, but he was quick out of the blocks with birdies at the opening two holes.
Three further gains and one bogey saw him reach the turn in four-under 32 before the journey home yielded birdies at the 13th, 16th and 17th.
“I’ve never won this one, so there’s a little bit of added pressure tomorrow to try and put that right,” said Hutcheon.
In-form O’Hara had four birdies and two bogeys going out before coming in one-under with eight pars and one birdie.
Having signed for nine pars on that stretch in the second circuit, the North Lanarkshire Leisure-attached player will be hoping it can deliver some birdies on the final day.
Waterville pro Higgins, who is bidding to repeat his 2016 success, signed for seven birdies to sit one ahead of Englishman Matthew Cort, who was out in 31 in his 67.
Craig Lee (70) sits eighth on nine-under, two ahead of Graham Fox (68) and three better than 2019 champion Alastair Forsyth (71).