I am not sure about the reason why, but that was the feedback from Jerry with Stainless Marine. A leak at the top riser joint will make reversion worse.

Griff we were on the trailer, I do agree that the angle in the water would make the riser angle steeper and most likely drain better. I plan to run it as soon as the weather cooperates and see how it does.

With all of the technology available and problems with reversion I’m surprised that water in the exhaust is still a thing. I know that it was the best solution at the time 50 years ago, but there has to be a USCG approved option available by now.

Update I was able to run the boat today, I put about an hour on it. After running I Idled for about 5 minutes then Pulled the riser, it was dry. Griff. I did notice the boat leans to the back more in the water than on the trailer that could lead to the riser draining slower than in the water too.