Yahmaha F200txra Misfires No Topend

I am new here and wanna give it a try. I have a 2002 yah. F200 The problems all started when fuel was 4+ per gallon and I decided not to fill up one day at the end of my trip like I always do. Since I have cleaned and flushed fuel system added a racor had the fuel injectors rebuilt V.S.T. cleaned new screens installed new fuel pumps $$$$ O2 sensor water tested for vaccume and fuel preasure and computer comes back negative no faults. My certified yamaha mechanic and I are @ our wits end. The boat will still not get up on plane it backfires out the carbs. I HAVE NO POWER. for a 21 foot sailfish with a 200 on it that boat flew. Also at the house or in a test tank the boat runs great but as soon as you put a load on it it fails.
PLEASE HELP!!!!!!!!!!!!!!!!!

[jaycough]

maybe blockage in the line. i would start at tank and move forward, also use air compresser to blow out line

[boats.net]

Check the cam timing and run a leak down test on cylinders to check valves.

I would have to say the fuel system is 100% new lines and all and its been gone over 3 times end to end i have done a comp. test but i will do those others the leak down and cam timing i will let you know over the weekend
THANKS