Need Help! 235 Rochester BC Leak

Please see photo, can anyone tell me what this plunger is? When I press the throttle it pops out is leaking out fuel or starter fluid? How do I fix it?

 

throttle plate worn?? it the throttle shaft end plug, see if the shaft has proper fit???
usually most fuel leaks on these are bad floats

 

Is it normal to leak a little from the throttle shaft?

 

mine did that, had to get the carb rebuilt due to a pinhole in the float that caused it to fail.