Re: How much water if any?
In my opinion, you are definately taking on more water that you should. The 15 sec of drain would not be too alarming (considering wet kids climbing in and out) IF you had not also stated you are running the bilge pump from time to time and getting water out that way as well.
With my I/O, it can sit in the water for an entire weekend and have several hours of use, with 5-6 adults getting in and out (wet) and I have stopped even trying my bilge pump (cause there is never any water---if it werent for getting caught in a rain storm two weeks ago---i would have suspected it didn't work)
At the end of a long weekend and a thousand beers later, when I pull the boat from the water, put the bow HIGH, and pull the plug, I get maybe 8-10 seconds of drain thru a small drain hole.
You got a leak somewhere man! Find it, fix it!