challenger 1

Hi  i am new to this site so i dont no if i am in the right area but I have a 2000 seadoo challenger with twin 717 rotax engines in it my problem is my right engine will no go to full rpm at full throtle until the boat gets on plane it will just rev to 4500 rpms until the boat get moving  i have cleaned the carb  installed new plugs checked compression and even took apart the fuel selector valve and have not found a problem.  I dont no what to check next any help would be apreciated thanks Luke 

Also the motors do not have rave valves