I agree with Mark, if it feels normal and starts normally when you pull the recoil starter, failing to crank properly or to start when you use the electric starter is a problem in the electric starting system. It has nothing to do with the carburetor or fuel system.
There are both mechanical and electrical things that can go wrong with the electric starter. As Mark said, you always begin by checking the voltage - right at the starter motor as well as at the battery.
