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The 73 I just purchased has a couple of issues with the fuel lines and venting.
It has the main line from the tank to the fuel pump connected, but the secondary line is there but not connected to anything by the fuel pump, it
has a rubber line on it with a bolt inserted.The line does go back to the plastic box on the side of the tank as shown in image below.
There is a line that does run down the drivers side from the plastic box to the front which is not connected to anything, I assume this would have gone
to the Cannisterif I had one.
My question is can I block off the lines coming from the tank in the image and then get a VENTED fuel cap for the tank ?
Should I be looking at changing the fuel pump to one with 3 lines one in, one out to carby and a return line
to the tank and getting a vented fuel cap ?
Is this a better option wit the Holley ?
While the motor and fuel tank are out this is the best time to get it right
At the moment the motor is out getting a new cam and timing gear, replacing large cam and Peter Jackson Idler.
Transmission is also out getting changed back from manual shift kit and high speed converter.
So I am doing other jobs and looking at my options for improvement.
I have pretty well decided to change the fuel pump to one with a return and re plumb the line back to the tank and
block off the line to the roll over valve and Cannister(which is not there)
Will replace fuel cap with a vented cap
That black, plastic boxy looking thing on the side of the tank is a fuel separator. Based on how it’s plumbed, I’d guess it was leaking. Amazing how brittle plastic gets after 45 years of exposure to gas fumes
if if you’re going to redo the return line, I’d suggest changing all of the rubber hoses and the separator too.
Last edited by CA-Legal-Vette; Jul 10, 2019 at 09:59 AM.
Not really a roll over valve, at least in the stock configuration. It allows the charcoal canister to capture fumes from the tank but separates liquid fuel.
The plastic thing on the tank stops raw fuel from entering the charcoal canister. It allows vapor to go to the canister. and vents the tank.
I would try to get the return line hooked up, always better to have it with the correct pump, but some C3's did run without the return line from the factory.
If you are not using the canister a vented cap is a must.
My 73 BB did not have a return line at the filter or the pump from the factory.
When I purchased it the fuel separator was cracked and the garage smelled so bad with gas fumes, I left the side door open for ventilation.
Once I replaced the separator no more fumes.
It runs fine, no issues and no smell in the garage even when I tried a vented cap.
The line does go back to the plastic box on the side of the tank as shown in image below.
Just an FYI in case you decide to keep the fuel separator valve. Per your photo, it is installed upside down and won't function correctly in that orientation.
73 Fuel lines and venting
