Jsun,
I know you are in a small market out there in Key West and I am sure everybody knows everybody (locals anyway) but I could not resist going back to the initial mechanic and having a conversation with him. The eventual solution seems like it's something he should have known and certainly wasted your money and valuable time. He should offer some free labor if you would ever let him touch your motor again that is... I had a bad experience with a mobile mechanic that was actually referred to me by a friend when I first purchased my Osprey. I have had to replace or fix everything that guy touched. Fuel lines, water pumps, starter.. what a douche that guy was! Sad thing is... he prob is still working in the Pinellas area hosing up other peoples boats.
Glad you found the issue and it was a simple one.
Tight lines,
B