I am not 100% sure but I have used both methods and I think the primer bulb is attached to the carburetor so I would think that you would have to find a carburetor that will adapt to the engine that has a bulb on the side. It is my understanding that the primer bulb acts like the choke would in putting fuel in the carburetor for the start up. Why do you ask this question is there a particular reason in mind?
A primer bulb stuffs more fuel in via vacuum so that the cooler vapors on a cold start engine have a better chance of igniting; more raw fuel = more vapors. The choke shuts off or minimizes air so that more gas, therefore, vapors, is/are exposed to the initial spark. If you find a compatible carb, you will also need an additional line to go into the tank along with a new opening in the tank for the line. Some systems use both a choke and primer bulb.
