I've not personally had my hands on one of these to "inspect and comment".

In theory.... as long as the air intake (at the back/top of the cowling) is not restricted, this cover could be utilized while running the engine.

I would NOT, however, recommend it be left in place for long runs (more for trolling, fishing, brush-areas, or that pesky back seater that can't keep his lures off the cowling).