fuel issue after car sits.

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dmopar74

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Kennewick WA
73 scamp, stock 225 /6

car runs great, the issue is after the car sits for a couple days the gas syphons back to the tank, only way to get the car started is to pour gas down the carb. once fuel is to the carb it will start no problem.

what is letting the fuel drain back to the tank? the fuel pump?
 
theres not much gas in it, the car more or less has sat for 3 years. every month or so it gets moved around and tinkered with, this started about a year ago.
 
Well rubber go's bad after time, check the hose from the sending unit to line and replace if necessary, and really it sounds like the fuel bowl just dries up.
 
Pump, filter, fuel "sock" in the tank.... Could be nothing at all.

Fuel simply evaporates out of a carburetor over time.

I see you are 29... Is this your first car without fuel injection. This may sound funny but many in your generation really don't know how to start a non fuel injected car.
 
My old truck will sit for about two week's, and I spin the starter for about 5 seconds and pump the heck out of it :-D then hit the key again for about another 5 seconds and pump the heck out of it again :toothy10:And then she fires right up, Yep I am old school :-D
 
it even drains out the in-line fuel filter. are there no check valves anywhere in the system?
 
Im also having the same problem in the other post Starting Problem my car does the exact same thing. Don't see how the fuel is evaporating overnight or in one day on my car. Maybe the rubber fuel lines need replaced, cause this is a real pain in the a$$ to deal with a few times a week!!!!
 
1968FormulaS340 said:
Pump, filter, fuel "sock" in the tank.... Could be nothing at all.

Fuel simply evaporates out of a carburetor over time.

I see you are 29... Is this your first car without fuel injection. This may sound funny but many in your generation really don't know how to start a non fuel injected car.
Click to expand...

haha no. this happens after 2 days, i could pump and crank on the starter for a half a damn hour and nothing. ive owned close to 20 vehicles, 2 of em were FI. i know how to start a car.

i can let my 73 dodge truck sit for months and not have this issue, its not evaporation.
 
Have you swapped in a new fuel pump? I have had a few with pin hole leaks that would allow every thing to leak back to the tank. Just a thought,
Frank
Afterthought do you have the charcoal canister? If so i have seen them cause this. Plug the line going up to the canistor from your fuel pump. Short term fix just over night.
F
 
I blame it on the modern gasoline. Gas is not what it used to be! I have found a new fuel pump check valves leak after about one month of use. The check valves keep the fuel from going back to the tank. Small leaks let the engine get fuel to run, but do not hold back when parked for long periods.

The low vapor pressure of modern gas forces the fuel back when hot. It also evaporates and goes sour easily. The fuel solvents and ethanol kill seals. I have given up, and just prime an engine with a spray of WD40 in the carb. It has only been about 5 years that this has been a problem for me.
 
KitCarlson said:
I blame it on the Al Gore gasoline.quote]

We have a politics forum... please don't post stuff like here. We don't want people thinking it's OK to include their political views in diagnosising
a hard start issue.

Trust me, Al Gore has nothing to do with his problem.....
Click to expand...
 
i have not put in a new fuel pump but will try that. i didnt want to buy a new one until i heard that could be the problem.

no charcoal can.
 
My 67 Barracuda with a 318 does the same thing. It has a new fuel pump and filter. It's the gas, it does evaporate! The only way to fix it that I know of is a electric fuel pump at the tank. A lot of work and expense to fix a minor problem. They make the fuel more volatile for FI motors. It sucks for carb'ed motors.
 
my duster does the same exact thing. the fuel filter can be bone dry after one day sometimes. i do have the charcoal canister but im pretty sure i dont have a line from the pump to it?
 
i had an issue simmilar to this with a 78 trans am (i know im cussing already) was an olds 403 with a rochester q jet. i got tired of pumping the petal all the time so i came up with an okie fix and added a check vaulve and primmer ball like a desil motor actualy worked perty good. though all i really needed to do was rebuild the carb to fix the problem lol.
 
My 69 Cuda with a 318 used to do this too until I changed the 2 bbl carb with a better/newer one. If it sat overnight it would take a lot of cranking to start it due to lack of gas in the carb. Now it starts better but if I let er sit for a few days I have to crank it a bit to get gas to the carb. I never did find an answer.
 
A friend of mine owns a junk yard and there has been more cars over the last few years come in and the only thing wrong with the car was the fuel system was messed up from the current gas.

The current gas is garbage and eats the rubber in the fuel lines and carb gaskets when it gets about 2-3 weeks old. If you drive your car often the fuel don't have a chance to attack it because you are constantly adding fresh fuel but if your car sits or you don't drive it much you will start having problems. You will also have valve trouble if you try and run the gas after it has been sitting for 3-4 months. The temperature and what part of the country you are in will also contribute to this.

As far as the fuel lines, the gas does drain out of the fuel line on most older cars but most of us don't notice it because the car will run off the fuel in the carb till the fuel pump refills it. If the carb is dry after a few days, you need to replace the gaskets and seals. Most of the time this will fix the problem.
 
My car has the same problem and when I get to half a tank the car starts to misfire then I top up the tank and it runs great. I think it might be pin holes in the fuel line.
 
Mine does the same thing. Doesn't bother me much because I know to expect it.
It can take over half a minute or so of total cranking time if it's been more than a week. No worries about the battery since it's on an automatic charger. I always plan on needing a little extra time.

With all that cranking, I know the oil is circulated by the time it does start. So at least there's something good about it...

If you do change the rubber fuel lines, the Gates SAE-30R9 works well. It's diesel rated and marine grade. Does a good job holding up against the methanol.
 
The correct answers was the one about the fuel pump check valve failure. Also about rebuilding the carb. If your choke and everything else is working correctly the starting procedure is; pump gas fully twice (This primes the engine and sets the choke on the cold/fast idle tab)..... start er up. If the vehicle sits for more than 4-5 days between driving; follow memike'''s instructions. It has been this way since I started driving mopars in 1970. I am a purist on my slant 6's; all choke assemblies are used and the heat riser tube is used. Now having said all this if you have choke issues all changes!

Later,
Bruce B.
 
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