See the brass washer around the pin? Behind that brass washer is an o-ring. The o-ring is leaking. To get at it, pop out the welsh plug on the opposite side of the connector, and pull out the pin & spring. Now stick a punch in the brass washer and rock it back and forth to remove the washer. Now you can replace the o-ring and put everything back together. You will need an o-ring, and a new welsh plug. The brass washer is held in by staking with a hammer & screwdriver.
Note: There are two sizes of the o-ring, according to year. Yours looks like the newer version from the picture, but I can't tell for sure. There also is an o-ring around the pin's valve seat, which you might as well order also.
EDIT: O-ring, pin is 307858. o-ring, valve seat is 305857, welsh (core) plug is 305243
EDIT, EDIT: Pretty sure you have the newer version (307858)
EDIT, EDIT, EDIT: Yeah after looking at it awhile, it is the newer version.
When you connect the hose you push in the 2 pins.----One is a valve that lets air in ( vent ) and one lets fuel out.--------A quality tank used in the 1960's and 70's ----- Far better quality than the plastic ones sold today.
OK I might have messed up then :/. Gas was only coming out and making the sucking noise when I would LET GO after squeezing the bulb. Maybe the tank was ok? And on the other hand maybe gas isn't supposed to leak at all? Because it was leaking. We went to high altitude yesterday and by the time I got back I could see gas on the tank.
Re-read my instructions. Stick a punch in the brass washer and rock it out. Yes, the little "divits" are holding it in. You will create new "divits" when you re-stake it.
Ok. So am I sticking the punch in from the inside where the orings are and rocking it out to the out side or rocking it in to the inside past the orings? Sorry I'm not the most savy at do mechanics.
OK, sorry but I gotta ask is it in the water and in gear? And shear pin not broken?