+1. Buddy had a 2000 Dominator with the angle-cut Corsa tips with internal stainless flappers. No external rubber boots. Took a lot of waves into the transom on anchor at LOTO and never had a problem with getting water in the motors.

Just had same happen to me .... Still have not figured it out. Aft exhaust valve full of water after engine ran fine... Could not turn...