318 fuel line empties after running hot. Why???

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cudaracer

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I have a mechanical pump with a fuel line hugging close to the block/intake, and a rubber hose (approx 3 ") connecting it to a cheap clear fuel filter, than another rubber hose (approx 12") that runs up to the brand new 600 eddie carb inlet.

So once the engine warms up, or gets hot, and I shut it off, it takes about 5-10 min and all the fuel runs out, as evidenced by the clear filter being empty, and I have to pump it all back in with the starter motor. Pain in the freaking arse.

Anybody know why?
I am about to reroute everything, eliminate the cheap filter and add a new fuel pump and replace the filter just prior to the pump. Should take care of everything, right?

And which pump do I want exactly? I will eventually be at about 350-380hp. Currently at about 250.

Thanks
 
My guess is a leaky diaphragm allowing fuel to drain back in the return line. As for flow later, you'll be more than fine with a stock pump.
 
cudaracer said:
I have a mechanical pump with a fuel line hugging close to the block/intake, and a rubber hose (approx 3 ") connecting it to a cheap clear fuel filter, than another rubber hose (approx 12") that runs up to the brand new 600 eddie carb inlet.

So once the engine warms up, or gets hot, and I shut it off, it takes about 5-10 min and all the fuel runs out, as evidenced by the clear filter being empty, and I have to pump it all back in with the starter motor. Pain in the freaking arse.

Anybody know why?
I am about to reroute everything, eliminate the cheap filter and add a new fuel pump and replace the filter just prior to the pump. Should take care of everything, right?

And which pump do I want exactly? I will eventually be at about 350-380hp. Currently at about 250.

Thanks
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I have the same problem with my 318 and mechanical pump. After I turn the engine off, you can actually see bubbles coming up the fuel line into the filter for a long time after the engine is not running. My filter is between the pump and the carb so it's easy to see. Then when I try to start the engine it takes a while and I have to pump the accelerator!!

Treblig
 
My guess is the fuel is vaporizing or boiling away. Most of us have a rubber hose somewhere that could be clamped shut with needle nose vise grip. That would prove or disprove drain back or boil off.
 
RedFish said:
My guess is the fuel is vaporizing or boiling away. Most of us have a rubber hose somewhere that could be clamped shut with needle nose vise grip. That would prove or disprove drain back or boil off.
Click to expand...

Now that you mention it......I guess all I would have to do is start the engine cold and only let it run for few minutes so it doesn't get hot. Then shut it off, if the bubbles still occur then I guess it the pump, RIGHT???

Treblig
 
Treblig said:
Now that you mention it......I guess all I would have to do is start the engine cold and only let it run for few minutes so it doesn't get hot. Then shut it off, if the bubbles still occur then I guess it the pump, RIGHT???

Treblig
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You wouldn't even need to run it. Pull the coil wire and allow the starter and pump to fill the system.
 
You will go through all that and waste your time and money doing it.
Depending on your intake style the fuel is simply evaporating away, and the best solution for it is an electric fuel pump.
Eddie carbs are horrible about fuel evaporation, especially with todays fuel.
(Think about this) How is it possible for the fuel to climb back up the needle and seat out of the lower fuel bowl?
It doesn't, and contrary to popular belief it's not physically possible.

A bunch of us have been there, done that, and have the T shirt. :)

The absolute BEST solutions to the problem are to reroute your fuel line, an electric pump and a constant running fuel return system. (heat blocking plates help, as well as insulators between the manifold and carb) but don't solve it.

The electric pump insures the carb bowls are refilled before startup, and the return system keeps the fuel temp down in the lines so the carb gets cooler fuel.

Also, a fuel filter that has air in it is zero indication of fuel flow.
(Another myth people will argue about, but true none the less)

Take it or leave it, but this just how it is.

Oh, and before you ask the question everyone else does.
"What changed if it was originally designed this way?"

Ethanol blended fuel boils way sooner than fuels used to, and eddie carbs are one of the worst carbs for heat soak.

The routing of your fuel line adds to the problem by preheating your fuel before it ever gets to the carb, by running through an engine heated aluminum fuel pump and following right along a hot engine block to the carb.
 
Remove the filter from the tank side of the pump. Reroute the lines away from the engine and/or insulate them. Make sure the floats are set properly on the carb (both of them). Us ehte insulating carb base gasket. My truck runs 190-195 and I've never had a heat soak issue. That's with 10% ethanol here. It does go away if the truck sits for a couple days but anything shorter than 48 hours and it will fire with a bump of the starter and a pump of the pedal.
 
Something beyond the thicker carb spacer to try that will cost nearly nothing. Slip a 3/4 split loom over the metal fuel line(s). The dead air space is insulating and
It'll look a heck of a lot better than wooden close pins LOL
 
RedFish said:
Something beyond the thicker carb spacer to try that will cost nearly nothing. Slip a 3/4 split loom over the metal fuel line(s). The dead air space is insulating and
It'll look a heck of a lot better than wooden close pins LOL
Click to expand...

Tried that with split 1/2 heater hose. didn't help
 
Lots of good ideas!!
But the electric fuel pump idea I'm sure about. I've bought three Holley (the nice ones, Holley RED fuel pump) in the last 4 years for my son's '46 Chevy (350 CI, 700R4, carbureted) so I don't trust them anymore. The ones I've bought aren't cheap but they only have a 90 day warranty.....I wonder why???

treblig
 
Keeping the heat away from the fuel lines is the first step to avoid vapor lock. Reflective foil shields are the key; the heat gets into the fuel line mainly via radiation from the engine, exhaust manifolds and pipes, etc., not by conduction. Black stuff like hose and wire loom absorb radaated heat and hold it in so don't work well if at all.
 
after years of this problem I agree that volatile new gas simply evaporates from old style carbs remarkably fast. I solved the problem with a relatively cheap Mr. Gasket vane type electric pump. just use it to prime the carb, otherwise the mechanical fuel pump pulls fuel right thru the electric pump. It took a while to find a flow through pump like this, but it works great and needs no return line or screwing around with what's in the tank. just wish they made them for a larger diameter fuel line, this works great for the warmed over 318 in that car but I think it would restrict the flow into my dual quad 340.
 
Will this work?

[ame="http://www.amazon.com/Airtex-E8011-Electric-Fuel-Pump/dp/B000DT7Y70/ref=pd_sim_sbs_auto_9?ie=UTF8&refRID=12CPYGBDVDXS1TZJ52EM"]Amazon.com: Airtex E8011 Electric Fuel Pump: Automotive[/ame]
 
So I went to the Airtex site and looked up E8011 - appears to be for a 6 volt system, but I found E8090 that has 3/8 hose fittings, 12v 30GPH and 5-9 psi. Now all I have to do is see if it will work in line with a mechanical pump...
 
Don't run the mechanical pump. Just use the electric.
 
RustyRatRod said:
Don't run the mechanical pump. Just use the electric.
Click to expand...

In my own oppinion, if you are not a purist this is the one and only best solution to a lot of fuel issue's people have.
I wouldn't have it any other way on my own car, because there are just so many advantages over a mechanical.

The carb is always full before the engine ever even turns over.
If you happen to run it out of gas it fires right back up without cranking for fuel.
You can use a recirculating system to help with heat soak.
It's comforting to hear your fuel system pressurize before starting.
If the pump is where you can hear it the sound changes if you are about to run out of fuel.
 
After reading the OP, then the suggestions, then the OP again, I'm not convinced it's an evap issue. If the fuel is running back into the pump, it could be a bad pump.

Have you checked for fuel in your oil?

Of course I've only had one cup of coffee, so..................

I could get on board with the evap issue if the carb was going dry, but the filter is a closed circuit. It seems as though evap would be more difficult when there is no air vent.

Get the filter full, clamp off the rubber line between the pump and the filter and see if the fuel stays there. If it does, then unclamp it and see if it disappears, if it does then I would start looking at the pump.
 
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