Why does my 25hp yamaha 2 stroke bog down at full throttle? should I bypass oil injection system?

I have a new tank, gas lines, rebuilt carbs, and new plugs... The symptoms are full throttle for 10 seconds then boggin & smokin for 10 seconds and then back to full throttle again. Back and forth, back and forth... Could this be the oil injection system? If so how do I byapss and just add oil to the tank?