have just purchased a xlt 1200 and has been rebuilt and only done 28 hrs,mechanics disconnected the oil injection,so am running on 40:1 premix with premiun fuel,only new to skis but cannot get it to run clean of the bottom,applying the throttle ,bit by bit gets it to go but dont want that in the surf ?where should i start looking first power valves,carburation,starts and runs alright,untill you accelerate,any ideas,cheers denzel