No throttle while running 1996 200 hp Johnson

We have a 1996 200hp Johnson Ocean Runner. It does not have any power when throttle is applied. Early last year (2019) we replaced the stator, the timer base, rebuilt all 6 carbs, put a new ignition switch, new power pack. It starts good, idles good, but when you put it in gear and go to get on it, it will not go full throttle and runs at less than half power. Has new fuel filter, water seperator, bubble, fuel pump.Does anyone have any ideas on what to check next. We've been told by a mechanic that it is not fuel related (just can't afford the mechanic again, that stuff gets expensive). Wanna fix the issue ourselves. Does anyone have any suggestions or have you gone through this before?

Check for spark.-----If you only have spark on one side then check shift interrupt switch.

Do a cylinder drop test on it.