You say your motor is a ’58. So someone has changed it over from a two line pressure tank? That happens anyway the only place it can leak is where the O ring is on the end of the hose connector. The two small pins vent the tank when the connector is hooked up. Make sure the O ring is there and not damaged or cracked.

dale

’58 Lark, right? Yes, they had a single line tank..Your fit probably is ok. See those two little pins that get pushed in when you attach the connector? One is a fuel valve and the other one is a vent valve. The one with a tiny brass washer around it is the fuel valve. There is a micro-sized o-ring behind that brass washer. I’ll just about guarantee that teensy o-ring is shot. That lets it suck air and slop gas out.

The o-ring is replaceable by knocking the core plug out of the backside. There are two sizes of the tiny o-ring. ’58 uses the smallest size. There is another o-ring in there too. Replace both.

• This reply was modified 3 years, 9 months ago by frankr.

By chance do you have the metric fuel line connector meant for Yamaha and some Mercury models? The hole is a little bit bigger and will fit sloppy. The connectors look the same.

If your tank is also a 1958 or slightly newer, it will leak out the vent when you connect the line if the tank is really full, because it’s a 2-way vent, activated by the pn that pushes inwhen you attach the connector. This was corrected a few years later by having the vent be one-way, which did allow the tank to build up vapor presure inside, but they no longer leaked gas if the tank was full. So if you have this early tank, either you don’t fill it quite all the way, or you get a newer tank.
Dave

I may have learned something here – I thought all the early single line tanks would leak there if they were full. I’ll have to look for #18 in the future.
Dave

1. Remove the core plug. Do that by poking a hole through it with a hammer and small punch, say about 3/32″. Now with the punch still in the hole, rock it to one side, which will lever the core plug out.

2. Push the valve pin out through the opening you just created. A spring will come with it. Pick the o-ring out of the hole.

3. Where the pin was, is a small brass washer. Lever it out like you did the core plug. With the brass washer out, you will see the teensy o-ring. Pick it out.

4. Put a new teensy o-ring in, followed by the brass washer. “Stake” the washer in by upsetting the aluminum around the washer with a hammer and screwdriver. It doesn’t take much, just enough to sort of dent it. You will see how it was dented (staked) originally.

5. Back to the core plug end, put in a new o-ring, followed by the pin and spring.

6. Now, the new core plug. Insert a new one, dome side out. With a hammer and suitable large flat-ended tool. flatten the dome till it is flat. Warning, don’t go beyond flat or it will loosen up again and fall out.

7. Replace the o-ring behind the air vent pin in a similar fashion. You know how to do it by now.

8. I could do the whole job in less time than it took to type all this.

• This reply was modified 3 years, 9 months ago by frankr.