spud02ie

in a gas engine doe you have to leave the filling line or the overflow line open in order for fuel to flow to the carb.

pettit

My Feedback: (23)

Some sort of vent to the atmosphere is needed, normally done with the vent line being left open on a 2 line system.

If you use a third line in the tank for filling or draining, it should be plugged with the vent left open.

Flypaper 2

I have the fill going to the bottom, inside the tank, and and fill it at the top of the firewall. The vent line goes to the top inside the tank, and vents out the bottom of the firewall. I leave them both open. You could plug one if you like, as long as one is left open.

DGrant

My Feedback: (4)

If you leave your fill/drain line(one that's attatched to a clunk) unplugged it will drain back out. That line has to be plugged if it's going to the bottom of the tank(so it can be drained as well). The vent line goes to the top of the tank for overflow/venting, that way it won't drain back from being in the fuel/gas. The vent does not need a plug.

Flypaper 2

Only one clunk, going to the carb. Fill line goes from inside the bottom, front of the tank, outside to the top of the firewall.

DGrant

My Feedback: (4)

Clunk, or no clunk...that fill line has to be plugged if it exits "below" the lowest portion of the end that's in the tank. Unless you do have your filler-end exiting near or at the top of the fuselage it will drain. I like my filler's tucked a bit under the fuselage, so I guess the cap is price to pay..don't know that I'd do it any differently.
I do run 2clunks....and it does work both ways I'm sure. With the 2clunks though, I'm more assured I can get ALL that fuel out of there if needed. Just me though...and I usually have a few clunks around anyways...if you don't have the extra clunk though....without it will work fine too .

Flypaper 2

As you say, the fill line is at the top of the firewall, outside the cowl.