I have a Briggs & Stratton motor model no. 406777-0128-E1. It will start but when I try to make the engine go faster it will not. I have checked the speed cable and it will turn the arm coming out of the carburetor. When I move the choke lever the engine will go faster but does not run very smooth. Do I need to work on the carburetor or is the fuel pump bad? :confused2: