1974 Spider 124
I do not have much to go on since Gas Sending unit, and pump hoses were all disconnected.
Sealed gas tank is in place with a new sending unit and new pump is purchased.
- - Need to know what hose goes where?
I can Identify the fuel inlet to the carb by the hose with the fuel filter. Directly on top of the fuel inlet hose is another hose connection that leads to the trunk next to the inlet hose.
The hose from the main carb inlet goes where? (Sending unit out?, Pump out?)
The second hose connected to the carb directly above the main inlet goes where? (Sending unit? Pump?)
There is also a line that is disconnected in the engine compartment that goes to the "Vent" mounted the drivers side wheel well.
Any help is appreciated.
Fuel Lines 1974
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18Fiatsandcounting
- Posts: 3798
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Fuel Lines 1974
Do you have an electrical or mechanical fuel pump?
I can't say whether this is exactly true for a 1974, but a typical installation (mechanical fuel pump) is the larger tube from the sending unit connects to a rubber hose that goes through the bulkhead in front of the gas tank where it connects to the metal tube that goes up to the fuel pump. This is the fuel supply line, and the rubber tubing is usually 5/16". From the fuel pump, it then goes to the carburetor inlet, sometimes with a fuel filter in between.
The smaller tube from the sending unit is the fuel return line. It follows the same route as the fuel supply line, and it ultimately connects to the smaller outlet on the carburetor, usually with 1/4" hoses.
Some carburetors have a vent on the float bowl that connects to a charcoal canister, part of the EVAP system. This canister also has a third metal line that goes back to the gas tank, to collect vapors from the tank rather than having them vent to the atmosphere. A third hose from the charcoal canister goes to the intake manifold through a small restrictor port.
-Bryan
I can't say whether this is exactly true for a 1974, but a typical installation (mechanical fuel pump) is the larger tube from the sending unit connects to a rubber hose that goes through the bulkhead in front of the gas tank where it connects to the metal tube that goes up to the fuel pump. This is the fuel supply line, and the rubber tubing is usually 5/16". From the fuel pump, it then goes to the carburetor inlet, sometimes with a fuel filter in between.
The smaller tube from the sending unit is the fuel return line. It follows the same route as the fuel supply line, and it ultimately connects to the smaller outlet on the carburetor, usually with 1/4" hoses.
Some carburetors have a vent on the float bowl that connects to a charcoal canister, part of the EVAP system. This canister also has a third metal line that goes back to the gas tank, to collect vapors from the tank rather than having them vent to the atmosphere. A third hose from the charcoal canister goes to the intake manifold through a small restrictor port.
-Bryan
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Bobfla
- Posts: 29
- Joined: Sat Nov 21, 2015 11:01 pm
- Your car is a: 1974 Fiat 124
Re: Fuel Lines 1974
- Carb image has green line that is gas inlet. Blue line that returns to the trunk
- Trunk image. Corresponding green and blue lines. To the right is the pump showing flow from left to right.
Which lines go to the tank/sending unit/pump hookup line. (electric is straight forward, only need fuel line info.
-thanks
-
Bobfla
- Posts: 29
- Joined: Sat Nov 21, 2015 11:01 pm
- Your car is a: 1974 Fiat 124
Re: Fuel Lines 1974
How about a specific question.
If the Green line connects to the pump out, The blue line connects where? Small line of sending unit?
If the Green line connects to the pump out, The blue line connects where? Small line of sending unit?
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18Fiatsandcounting
- Posts: 3798
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Fuel Lines 1974
I'm not sure I'm following you here.
On the fuel tank sending unit, there should be two tubes coming out at an angle. The larger one is the fuel supply, and that would connect to the input of your fuel pump. The output of the fuel pump would run all the way up to the engine bay and connect to the inlet of the carb (larger brass fitting).
The smaller tube on the fuel tank sending unit is the fuel return line. It would run all the way up to the engine bay where it connects to the outlet of the carb (smaller brass fitting).
Does that help?
-Bryan
On the fuel tank sending unit, there should be two tubes coming out at an angle. The larger one is the fuel supply, and that would connect to the input of your fuel pump. The output of the fuel pump would run all the way up to the engine bay and connect to the inlet of the carb (larger brass fitting).
The smaller tube on the fuel tank sending unit is the fuel return line. It would run all the way up to the engine bay where it connects to the outlet of the carb (smaller brass fitting).
Does that help?
-Bryan
-
Bobfla
- Posts: 29
- Joined: Sat Nov 21, 2015 11:01 pm
- Your car is a: 1974 Fiat 124
Re: Fuel Lines 1974
Brian
Yes that answers everything. The return line was confusing and made me doubt how the rest was connected.
Thanks
Yes that answers everything. The return line was confusing and made me doubt how the rest was connected.
Thanks