Re: High speed flooding over transom
Well, once I Googled Apex A-11, I found out that it's an inflatable. We don't know the models of all boats instantly, I'm afraid. It really helps if you describe your craft a little more when you ask questions.
This is more of a boat question than an outboard question, but I'll take a stab at it.
The usual reason for flooding under way is an outboard that is running too deep in the water. On your inflatable, does the stern hang low in the water when you're running it at high speed. If so, then the outboard may be running deeper than it should. Also, is this a short shaft outboard? If it's a long shaft, I guarantee that it's running too deep. Is there anything else at all attached to the transom?
What position is the outboard trim set at. You might try changing the trim angle to see if that helps.
There are a bunch of folks who run inflatables here on the forum. You might try posting your question in the Boat Topics and Questions section. Someone who also runs an inflatable like yours might have a better idea about your problem.