I have a 1986 20hp mercury outboard motor that runs only at half throttle. I replaced all the fitting from the fuel tank to the motor.Replaced the bulb in the fuel line checked and cleaned the fuel filter. I now get a good fuel flow to the carb. the motor now starts fairly easy, but only runs at half throttle. I am now going to get a carb kit. I am not much of a mechanic,is it a difficult to rebuild the carb or should I send to a repair shop?