Gas vent tube?

[K10-Kansas]

Hi. Is this fuel line supposed to be like this?

[truckster]

There are no fuel lines that are open to the atmosphere...

[badpeanut]

Are these fuel lines on the underside of the gas tank?

I would guess one could be supply and one could be return, but I've never seen a return on the bottom.

[K10-Kansas]

Originally Posted by badpeanut

Are these fuel lines on the underside of the gas tank?

I would guess one could be supply and one could be return, but I've never seen a return on the bottom.

Yup the one closest to the tank runs through the floor and then into the front of the truck. The one going through the floor closest to the seat runs through the floor and is cut off. 8n the cab in the cab it runs to the roof in a cavity and then returns to the tank.

[ray_mcavoy]

That vent line (that currently ends off under the floor) originally ran up to a charcoal vapor recovery canister in the engine compartment. The canister stores up gas fumes that evaporate from the tank. A purge line ran from the canister to the carburetor to draw out the fumes (and burn them in the engine) when running.

The loop that runs up inside the cab is a liquid-vapor separator to keep any liquid gasoline from making it's way into the vent line / canister.

[K10-Kansas]

Originally Posted by ray_mcavoy

That vent line (that currently ends off under the floor) originally ran up to a charcoal vapor recovery canister in the engine compartment. The canister stores up gas fumes that evaporate from the tank. A purge line ran from the canister to the carburetor to draw out the fumes (and burn them in the engine) when running.

The loop that runs up inside the cab is a liquid-vapor separator to keep any liquid gasoline from making it's way into the vent line / canister.

Awesome, thanks. I'll see if LMC has those parts.

[PbFut]

I am all for pollution control but I think this venting system is some what over doing it relative to net gain in environment protection given how dirty these motors actually run. Unless doing a full restoration,I would cap the line, run a vented filler cap and call it a day. If you are already running vented cap then this system is worthless. If you are running nonvented cap you can convert by removing the spring and rubber valve. Though this mod to the cap may be an issue in a roll over as it could leak fuel.

[71CHEVYSHORTBED402]

Originally Posted by ray_mcavoy

That vent line (that currently ends off under the floor) originally ran up to a charcoal vapor recovery canister in the engine compartment. The canister stores up gas fumes that evaporate from the tank. A purge line ran from the canister to the carburetor to draw out the fumes (and burn them in the engine) when running.

The loop that runs up inside the cab is a liquid-vapor separator to keep any liquid gasoline from making it's way into the vent line / canister.

Exactly. First time I've heard someone say that loop (AKA vent pipe assembly) is in fact a separator.

That truck probably wasn't equipped with a RETURN line, they started that business in 72. Your vent line appears to be wide open, and perhaps a tad dangerous? I recall someone recommending a valve of sorts for that situation, though post 7 looks like a good idea.