# hard start after sitting



## colobronco (Jun 3, 2012)

After the car has been sitting for just a couple of days, it's very hard to start. I usually have to prime the carb with some fuel. Once running it runs like a champ. once started the accelerator pump is working good, after two days it don't squirt anything. Pulled the fuel line from the carb and it is empty. there is a metal filter just before the carb, behind the alternator, its empty. Down on the pump i get some fuel out of the line, but not much. 
Is there a check valve or something to keep the fuel from flowing back to the tank? Napa said there should have been a Mesh filter up in the carb, it had been removed. that i don't think would have done it. 
I did replace the rubber fuel lines yesterday, and will check the accelerator pump today or tomorrow to see if i get some fuel.
I haven't' pulled the top plate off to check the bowls or float levels yet, testing the fuel line replacement. 

guess my main question is about the check valve/ backflow preventer. what stops the fuel from draining?

Just updated the signature, the carb is the stock 4 barrel, AFB ( i think)


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## the65gto (Oct 9, 2008)

It "may be" nothing more than a hot engine/carb is evaporating the gas. Some have put a thermo isolation plate between the carb and intake. ???


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## Matthew (Feb 11, 2011)

OK, so the needle and seat I think you are talking about is controlled by a float. As the fuel bowl fills the float forces the needle onto the seat restricting the inlet. The fuel should stay in the bowl, but as the65gto points out, you could have a heat soak problem forcing fuel out into the venture. You should be able to see this immediately after shut down. Take your air cleaner off and observe the carburetor. You would see vapor rising from the air horn opening. 

The fuel line to the carburetor would kind of always appear to be empty when the car is not running - that is normal. You have a brass fuel filter at the carburetor inlet. What the guy from Napa is saying is there should be a paper filter there. It is one or the other - not both. Sounds like you have the correct one. Now, these things are cheap. Replace it and see if things improve. If not, you have eliminated one thing. 

You said you have some fuel run out at the fuel pump when you took the line off. That would tell me you are not pumping all the way from the tank when you try to start the car. It is completely possible you have a worn out pump. Do you know how to check it?

Matt


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## chuckha62 (Apr 5, 2010)

To piggy back a little on what Matthew is saying... If you decide you need a new fuel pump, be careful to get the right fuel pump (AC Delco, if you can find it). Aftermarket pumps tend to be calibrated MUCH too high in pressure and will unseat the needle and seat at idle. This will cause a rich condition that will keep you running in circles. The AC Delco pumps tend to be calibrated to 4.5-5 PSI, which is all you need, as long as you have the fuel volume.


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## jmt455 (Mar 26, 2012)

If you're running a Quadrajet carburetor, you might find that the plugs at the bottom of the float wells are leaking. It's a very common issue on these carbs.

The best "permanent" fix is to disassemble the carb and remove the pressed-in float well plugs, then drill and tap the holes for pipe plugs. Install the new pipe plugs with epoxy sealer (make sure you use the fuel-resistant epoxy).


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## geeteeohguy (Feb 2, 2008)

I agree with all of the above. My bet is that the only real issue here is today's highly volatile fuel evaporating away in a short time after a hot shut down. Both of mine do the same thing, my '67 Q jet and my '65 Tripower. But it takes about a week. The fuel in the float bowl(s) is what allows the engine to fire right up and the pump to start pumping at a good rate.....the only way fuel will leave the bowl is evaporation or leakage, period.


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## colobronco (Jun 3, 2012)

thanks for the replies, i will check to see if the fuel is evaporating out the carb. After i replaced the fuel lines, the one on the inlet side of the fuel pump was pretty dried out (tore in halve when trying to get off metal line from tank), I took if for a long drive and pretty hot day, the next day it did fire up right way with fuel squirted when pumping the petal. 
i'll let you know what i find. thanks all


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## skurfan (Sep 19, 2012)

Another option....over time, the rubber sections of your fuel line can develop small cracking. Gas does not leak generally, but will slowly evaporate. I replaced my rubber lines in my '55 Safari and the problem cleared right up. Fires right up now after sitting for weeks.


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## Richard Boneske (Jul 29, 2008)

All the carbs used in this era had large vent holes for the float bowls. The Tripower setups, single two barrel, Quadrajet have vents about 1/4" diameter that allow gas to evaporate within a few days. No matter what you do, this will continue. 

If you doubt what I've said above, take the top off your carb after the car has been sitting for 4-5 days and you'll find the float bowl empty or near-empty. The hotter the weather, the more evaporates. 

If hard starting bothers you, pour a few tablespoons of has in the carb inlet before turning the engine over. Better yet, turn it over until oil circulates, then pour some gas in.


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## Sal (Nov 9, 2016)

colobronco said:


> After the car has been sitting for just a couple of days, it's very hard to start. I usually have to prime the carb with some fuel. Once running it runs like a champ. once started the accelerator pump is working good, after two days it don't squirt anything. Pulled the fuel line from the carb and it is empty. there is a metal filter just before the carb, behind the alternator, its empty. Down on the pump i get some fuel out of the line, but not much.
> Is there a check valve or something to keep the fuel from flowing back to the tank? Napa said there should have been a Mesh filter up in the carb, it had been removed. that i don't think would have done it.
> I did replace the rubber fuel lines yesterday, and will check the accelerator pump today or tomorrow to see if i get some fuel.
> I haven't' pulled the top plate off to check the bowls or float levels yet, testing the fuel line replacement.
> ...


My 65 has the same problem. I was thinking about putting a electric fuel pump in line, your thoughts?


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## the65gto (Oct 9, 2008)

Sal said:


> My 65 has the same problem. I was thinking about putting a electric fuel pump in line, your thoughts?


My experiment, had a switch mounted on the end carburetor so that during WOT, the electric fuel pump would kick in and shut off when I got out of the throttle. (Used a pvc valve to bypass the electric fuel pump). The experiment ended when I kept having mechanical fuel pump inlet valve failures. To much pressure from the electric. :surprise:


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