Question:

[THEFERMANATOR]

Lets say your running along and get some grass on your lower unit, not enough to cause you to come off plane, but just enough to allow the water pickup to suck air in. With a rubber impeller no big deal as it will continue to pull in the aerated water mixture, BUT your centrifigal pump could stop pumping all together as soon as some air hits it. I understand your way of thinking, but I still feel there is a reason for sticking with a tried and proven design. And it comes down if it aint broke, don't try and fix it. I'm willing to bet others have tried running centrifigal pumps on outboards, and I would bet they found out real quick they didn't work well on engines that can ingest an air water mixture at speed.