510 evap system questions

[Stitebunny]

I have a 1970 510 wagon that seems to have some parts missing from the evap system. The flow control valve, (mounted under the hood on or near the left fender, thanks Mike) is missing. Does anyone know where the vapor seperator is located? Under the hood I have 2 fuel lines entering near the right headlight. One is the supply to the filter and carb. The other one is attached to nothing. I was thinking this is the one for the evap system. When I fill my gas tank full, fuel runs out of this hose. Scary! If the seperator is located upstream of this hose, does that mean it's bad and not doing it's job? Or is that missing too and suppposed to be under the hood? I have located a flow valve to install but need more info on the seperator and it's location.

Thanks for any help. And pictures of a funtional system would be great if anybody has an original setup.

[DanielC]

This is a wild guess from knowing where things are on a 521 truck. The vapor separator on a 521 is located pretty much directly above the gas tank. in is in the bed of the pickup, just ahead of the left rear wheel, and close to the fuel filler.

 

I am going to guess you look in the trunk, on the same side as the fuel filler on the outside of the car, up under the rear deck.

[ggzilla]

Vapor separator is number 23 in this diagram (reservoir tank). The critical thing is that the vent line (to crankcase) is supposed to go up over the reservoir then down and up to the front of the car. This loop up is to prevent siphon effect.

 

[Stitebunny]

That's great info guys! Thanks. Looks like maybe it's in the right rear quarter area? I'll check it out tonight and see what I can find.

 

 

[Stitebunny]

Well I just had a look around and I don't think my car had this system from the factory. There are 2 fuel lines from the tank. They go to the engine compartment. One other line is the vent from the tank to the filler neck. All I can think of is that the hose that leaks is a fuel return line. Since it's not hooked up anywhere (I have a Weber 32/36) it's leaking fuel when the tank gets topped up all the way. So I'm wondering now if I just cap this line, will there be a venting problem? I can't find any other info on this. How did the tank vent during orginal operation? I have a locking fuel cap which looks original and can't tell if it vents or not.

[ggzilla]

Two lines go to the front:

* Fuel feed line

* tank vent line

 

Question is why is fuel leaking out the vent line?

[Stitebunny]

I found a Haynes manual and it shows an "old" system, up to 69 and a "newer" system from 70. The old one looks like what I have without the seperator. The car is a 12/69 production and must be on a split. My 72 wagon, 7/71 production has the system that is shown here in this thread with the seperator.

So now that i have that info, I just need someone to tell me how it is supposed to work. 'Im thinking the hose that is leaking is a return line still. And when the tank is full it's filling up that line and spilling out. That is my only guess as to why it's leaking.

[ggzilla]

The old system is non-EVAPO. The new EVAPO started in 1969 mid-year, supposed to be before December.

 

Is your line going up in a loop above the level of the tank?

[Stitebunny]

The lines exit the tank next to each other from the top and run parellel down the car to the engine compartment. There is about 18-24 inches of the open hose coiled under the hood.

 

 

[ggzilla]

If that is a return line, then you can plug it. Return line is not needed. Just make sure your tank is vented.

[Jester]

It's leaking because the line is a return and is lower than the fuel level when your car gets a fill up. Once the fuel level is bellow the top of the tank, it's fine.