visual is OK, but a moisture meter would be better. What do you mean by "foam delamination in the engine compartment". If it has foamed in floatation, and that is coming out, no big deal. I just pulled all the old foam out of mine when I took the deck off to replace the gas tank. I did find cracks at the end of some gussets that was covered by foam. Check out this thread: http://www.donzi.net/forums/showthre...highlight=deck