Marchand netted both of his goals in the first period as the Bruins jumped out to a 3-0 lead and never looked back.
Dennis Seidenberg doled out three assists while Andrew Ference and Rich Peverley each added a goal and a helper for Boston, which recorded its fourth win in five games and pulled to within one point of Montreal atop the Northeast Division.
Rask stopped all 30 shots he faced over the first two periods en route to the victory.
Patrick Dwyer and Drayson Bowman each found the net for the Hurricanes.
Justin Peters started in goal for Carolina, allowing two goals on four shots to start the game before being pulled.
Dan Ellis relieved and turned aside 28 shots the rest of the way.