mmills023
Member
I had that exact problem. Drove me nuts for about a year. Turned out to be that the cheap plastic thruhull for the cockpit drains had cracked. Water was forced through the cracks when on plane. I replaced them both with 2" marelon and problem solved. I especially enjoyed wedging into the corners on my back to do the remove/replace.
By the way I also removed the transom rub rail and rebed that joint. It had some areas where the bedding was completely gone. It's pretty easy to remove and re-install that full rubrail.
As affirmation I just bought a 400 and it had that exact problem - was the cockpit drain through hulls. I my case I had the PO replace large in part due to write up ZZ13 did abot how much of a PITA they were. Love this forum!