Help Please, I purchased a 2002 Yamaha XL-2000 in June and it has been in the shop every since. The boat ran great on the port engine 7000 RPMs. The starboard engine will not run past 3000-4000. The mechanic has rebuilt the carburetors twice and all I know is it sure seems fuel related. Starts perfectly, runs smoothly but will not go past 4000 RPMS.

Work Completed todate
Carbs rebuilt
New engine
New stator
Spark plugs
New fuel lines
New fuels pumps (6 fuel pump carburetor kits)
#1 coil
Tanks cleaned
All filters replaced
Inline fuel injector pumps

Any help would be appreciated.