Scanlon recorded his second straight double-double and Mahoney only missed three of his 10 attempts from the field.
Javante McCoy scored 10 points off the bench for BU (11-12, 4-6 Patriot), which also snapped Bucknell's 15 game home winning streak earlier this season. Jonas Harper made his first career start and finished with four points and two steals.
Alex Vilarino scored on a contested layup in the closing seconds of the first half to extend BU's lead to 38-25. Scanlon had 10 points at the break.
Colgate, which never led, was within 67-64 with 4:18 remaining but didn't make another field goal.
Teske takes out ref while saving the ball
Jon Teske knocks over the ref while saving the ball from going out of bounds leading to a Jordan Poole layup.
Georgia St. tops UTA 73-64 in Sun Belt final for NCAA bid
Malik Benlevi hit four 3-pointers and finished with 16 points, and Georgia State advanced to a second straight NCAA Tournament with a 73-64 victory over Texas-Arlington in the Sun Belt Conference Tournament final on Sunday.
Georgia State captures the Sun Belt and NCAA tourney bid
Georgia State tops UT Arlington 73-64 for the Sun Belt Tournament Championship and a NCAA tournament berth.