Fowlie scored twice and added an assist for the Rockets (44-15-4), who also beat Victoria on Friday night, and Goulbourne had a goal and two assists.
Jesse Lees, Colton Sissons, MacKenzie Johnston and Tyson Baillie each scored once to round out Kelowna's offence.
Jack Walker and Jordan Fransoo scored for the Royals (32-24-5), who are winless in six games.
Jordon Cooke made 26 saves for the win as Patrik Polivka took the loss after allowing three goals on six shots in the first six minutes of the game. Coleman Vollrath replaced Polivka and stopped 27-of-31 shots in relief.
Kelowna went 3 for 7 on the power play while Victoria scored once on five chances with the man advantage.