I saw fountain Express with exhaust tips turned down. They look like they are definitely under water with boat just idle.
I imagine this is to keep it quiet when off plane but wouldn't this be water reversion waiting to happen???.

Guessing they have internal flappers, also solid water actually helps with revision as it doesn't allow air to be pulled back in, acts like a damper of sort.

My 35 fountain lightning came with underwater exhaust, reversion not a problem as the tubes are submerged at idle and open when on plane.

My understanding is that reversion is more likely at idle.

Turn downs will not cause reversion.

Well dammit turn them up!

so the water is harder to pull up the exhaust when submerged??? . It would be a great way to quite my rig down. I have longer cam 246 at .05 lift.

What if engine diesels