I think I may have isolated the reason my carb refuses to not-flood...

... So I replaced fuel lines quite a while ago due to breakage/decay and as a result *BROKE* the plastic-breather thing that's attatched to the body above the fuel tank. I, being a dumbass, instead of finding out exactly what it did or how it worked and so on, capped the line.

Now; my tank is developing positive pressure, and (here's the kicker) is developing that pressure in such a way that fuel is coming from the tank by way of the RETURN line.

So... All that meddling with the seats, taking the carb apart four hundred thousand times and so on was for naught; as the fuel was finding its way into the device from the vent.

tl;dr: What do I do now, and do I have to drop the fuel tank (again) to do it?

Thanks

 

Fuel cannot flow to the carb via the return line because the restricter in the rubber line between the carb and the hard line at the firewall is also a one way valve. Unless you removed the restricter. Also the return line terminates just inside the tank ceiling, so fuel can't be forced back into it.

Most likely fuel is being pushed past the needle/seats on the supply line due to the pressure build up. If you don't wish to drop the tank, drill small hole in the gas cap.

 

I was looking at the (bad) diagrams and pictures in my Haynes manual and came to that same set of conclusions. The one-way valve doesn't fully work, so I may have the hardline-> tank plumbing screwed up... Film at eleven.

 

Watching this thread with interest... As I'm still trying to overcome my after-driving flood condition. & I've got a smog check coming up in March, so it's moved up the priorities list.