One more thing. I just figured out how to get a close up of your carb pic. I think that fuel bulb is missing lines!
The fuel bulb is normally plumbed inline with the fuel tank pickup line. The plumbing looks like this:
Fuel pickup in tank --> Primer bulb input barb --> Primer bulb ---> primer bulb output barb --> carb fuel inlet --> carb excess fuel outlet --> tank return line
When you push and release the bulb, it creates a vacuum in the line to the fuel pickup in the tank, which sucks the fuel into the bulb and forces it down to the carb fuel intake. There's a fixture in the carb that allows fuel to be siphoned off by the venturi created by the carb's air intake. Additional fuel under excess pressure from the bulb flows back to the tank via a return line.
The fuel bulb is normally plumbed inline with the fuel tank pickup line. The plumbing looks like this:
Fuel pickup in tank --> Primer bulb input barb --> Primer bulb ---> primer bulb output barb --> carb fuel inlet --> carb excess fuel outlet --> tank return line
When you push and release the bulb, it creates a vacuum in the line to the fuel pickup in the tank, which sucks the fuel into the bulb and forces it down to the carb fuel intake. There's a fixture in the carb that allows fuel to be siphoned off by the venturi created by the carb's air intake. Additional fuel under excess pressure from the bulb flows back to the tank via a return line.