Yamaha 25esh fuel problem?

[BANDEDJESTER]

I have a 2006 model yamaha 25. Starts and idles fine, take off from stop and runs perfect for 25-30 sec then slows slightly for 1-2sec then runs normal for 6-8sec and then slows for 1-2sec this happens constantly for as far as you wanna drive. If u stop and idle or kill it and restart it, its the same routine 25-30 sec normal then slows, i can here and feel it. Ive cleaned carbs (dual carb) replaced diaphragms in fuel pump and replaces all fuel line and tank thinking it could be sucking air or tank creating a vaccum, (ran motor with fuel tank cap off) still nothin changes. My air adjustment screw on top carb is broke off flush and i cant budge it, but it is still at factory setting. What is wrong with my motor?