Wiebe shared the lead after Friday's first round and grabbed its sole possession Saturday, finishing 36 holes at 11- under-par 133 at En-Joie Golf Club.
A three-time Champions Tour winner, the 53-year-old Wiebe last tasted victory in a playoff two weeks ago at the Greater Hickory Classic.
First round co-leader John Huston posted a 2-under 70, dropping into second place at minus-9.
Alone in third place at 8-under 136 was Jay Don Blake (68).
One shot further back were Joey Sindelar and Bobby Wadkins, who both shot 3-under 69s.