Possible fixes for fuel draining back from carb

[Calif240]

I've been doing some research on fuel draining back out of the carb, as my engine takes a few starts to kick if it has been sitting longer than 2 days. However, once it has been started, she fires quickly and easily. I've heard you can fix this problem with an electric fuel pump. I've also heard some newer carbs are better at keeping fuel up. My question to you guys, is A) are there any simple fixes or improvements to the current setup of mechanical pump and older edelbrock carb that could help, and B) are there any new mechanical pumps that are better at not allowing fuel to drain? I figured there has to be some product(s) out there that could help that I'm unfamiliar with.

Any thoughts or suggestions are very much appreciated.

Thanks guys,
Terry

[mauve66]

 

[John_Kunkel]

Fuel can't drain "back" from the carb, there is an air gap between the top of the fuel in the bowls and the inlet line so there can be no draining or syphoning from there. Fuel can leak from the bowls externally (pretty obvious) or into the intake manifold.

The problem is more likely simple evaporation, gas nowadays is more volatile than in the past.

[resq302]

Fuel can't drain "back" from the carb, there is an air gap between the top of the fuel in the bowls and the inlet line so there can be no draining or syphoning from there. Fuel can leak from the bowls externally (pretty obvious) or into the intake manifold.

The problem is more likely simple evaporation, gas nowadays is more volatile than in the past.

I agree that your problem is probably the evaporation issue.  Ive noticed anymore that I have to crank over the car a little while before I stop it, give it two pumps to set the choke, and then it fires right up.  Same with the challenger.

[mudda_hunchie]

Evaporation makes sense.  My 70 chager does the same thing.  Still don't know what to do about it.  It's hell on my starter!

[FLG]

I notice a lot of guys are having this issue?? When the charger was running i went a month without running it whle i was on vaca...came back and few cranks and she fired right up...when i used it regularly shed start up no problem. Is this an issue with certain carburetors maybe?

[charger Downunder]

You could always put a check valve in the line.

[resq302]

A check valve will be a waste of money.  Think of water in your garden hose.  If you bleed off the pressure in the hose and then coil up it up, you leave the nozzle on you have no where for the water to go.  When you coil up the hose, water will still be inside the hose and will be sitting at the lowest possible point before there is a bend or high curvature in the hose.  Now think of your fuel set up.  Gas tank is a certain height, then the rubber flex line comes either out and up or out and down causing a point where fuel will be trapped, now the fuel line up to the fuel pump is probably lower than the fuel tank, so that should have fuel in it also.  Fuel pump going upward to the carb might have fuel bleed back through into the lower portion of the fuel lines causing some to get pushed back into the tank.  However, the carb is now the highest part of the fuel system and there are bowls inside the carb which are again lower than what he inlet is for the carb.  There is no way for the fuel in the bowls of the carb to get out and go back downstream towards the fuel pump.  There can be a leak in your carb which could cause the fuel in the bowls to drain out also which would be the only reason why they would leak out.

[Just 6T9 CHGR]

Took off my crap Carter AVS & put back on my Holley.... The Carter would always give me hell even after 1 day....Guess what?  Starts right up after days.... I even have the chokeless HP main body as well!

[mudda_hunchie]

I got to thinking and i don't know about the evaporation deal.  I also have a '80 chevy truck.  350 4barrel.   It doesn't get as much service as the charger.  Pat the gas three times and it cranks on the second turn.  Also had a '78 ford that did the same.  Maybe it's my eddieflop carb.  That's a whole nother story. :think

[y3chargerrt]

My edelbrock 750 seems to need to be cranked a while after sitting say a week or more. A guy that stores his Chevelle in the same garage doesn't have that same problem. He is running a Holley carb. He says his will start right up after sitting for months. I don't think he is running an electric fuel pump. So I don't think its just the gas thats the problem.

[resq302]

Ive noticed the same with the Quadrajet on our 70 el camino SS396.  The elky would fire right up after sitting for days.  I guess it has something to do with the bowl vent set up in the Carters which allows the gas to evap.  I don't think the holleys or Quadrajets have that type of set up.