Ah a rotary clone with built in primer. It could base either the Walbro WY series or the Zama RB series. That may be a problem depending how true they were to the original design. It does sound like you are having a problem fitting of the primer bulb to primer problem, I have seeing a lot of Chinese clones showing here too on many of the engines here. I just got through with a Haulong HQ-2 replacement as the carburetor was only a few dollars less than the whole carburetor.
