I have 3 tanks….1 I bought last night on CL for $30 bucks, and it’s like new, another that I bought last year that’s in "OK" shape which I used last summer, and a 3rd that’s a rusty specimen. I’ve never really looked at any of the connections very closely at all & now come to realize that I don’t even understand how they really work.

3 questions come to mind:

– The 2 pins: one is clearly a shut-off valve for the gas pickup tube, but what does the other one do? I press it and can neither blow nor suck air through the pickup tube. If it does something, I can’t figure out what.

– The hose connector: when I snap it on to the tank, it doesn’t seem to sit face-flush to the tank connector on any of my tanks; the connector is being "pushed away" by the pin that activates the valve. Is that normal?

– Lastly, When I squeeze the bulb on the hose, am I simply sucking from the tank & pushing to the engine, or is there more to it than that?