Bob's problem could be a number of things, I was just sharing my experience with similar symptoms.
Yes, it was 2003 282 Sailfish Twin F225 1100 hours. In 2017 had the dealer do the scope as was frustrated with performance. Upon further inspection the port outboard dry exhaust stack actually had a hole through it on one side. When inspected the base of the power head it has been damaged by the corrosion and would have needed replacement. Similarly, the starboard outboard showed corrosion on the upper portion of the dry exhaust stack.