carb question chevy, but not on a Z

[SBC_400]

if this does not belong here, I am sory and ples move to the appropriate forum.

 

I am working on a 1960 impala, and I just rebuilt the carb, a carter wcfb and it is running like a top, when it runs. it seems to be draining all the gas out when it sits for a couple days and will not start again unless i poor gas down the carb to get it going. this was a problem before I rebuilt the carb as well, but it runs much better now after the rebuild, but it is still dry after it sits for a little while. if it run one day, it will start the next, but not 2 or 3 days later.

 

i replaced the needles and seats, the gaskets, set the floats, the bowl vent and the throttle plate, and after that reset the idle jets, but in the kit there was another needle (no seat for it) and a small steel ball that i could not find anything about them in the carb, or in the diagram that cam with the rebuild kit. could these have anything to do with the float chamber draining?

 

is there any thing else it could be?

 

again it is a carter wcfb on top of the 348 in a 1960 impala.

 

thanks in advance

[Lason]

The problem may be with the fuel pump as well. I dont think you mentioned if you were running a electric or mechanical pump but I have always had this problem with mechanical pumps. After a couple of days the line pressure bleeds off and you need to crank it quite a bit to get the pressure back up. You should still have fuel in the bowl though so that has always had me a little stumped. I can tell you that in my expirience a switch to an electric fuel pump has fixed that problem for me everytime.

[Mike kZ]

I have a 1962 409 impala convertible, and does the same thing. It sounds like a common problem.

[veritech-z]

My SUs used to do this if the car sat for any length of time. It was cold starts really that would do it. Anyway, my theory was that the fuel was evaporating out of the bowls through the vent holes at the top. I have my electric pump on a switch to come on whenever I want, so I would just leave it running for a few seconds before I started the car.

[SBC_400]

what ever the problem with the fuel draining, it started just this summer, and strangely enough right after a fresh fill up and using a lead substitute that we have never used inthe car before because track was out of the stuff that we normaly put in it. i dot realy think that this has anything to do with it, but it is a strange coincedance.

 

i was hoping to avoid putting in an electric pump becasue the car is an all original survivor car, but it seems like that may be the thing to try.

 

does the mecanical pump have a check valve in it that could have gone bad, or would it just be the diaphram itself?

[Lason]

If your worried about originality then I would try swapping over to another mechanical fuel pump like a edelbrock or holley pump and see if that helps. I always gave up on them and just threw a electrical pump on them at the first signs of trouble.

[Pyro]

Try pulling off the carb, fill it with fuel, let sit on the work bench a few days to see if it is leaking out.

[dustin280zx]

i agree with veritech-z....your gas evaporates out of the fuel bowl. but it would take more then a couple days to do that. i know in our wood truck after sitting over the summer i just dumped alittle gas in the carb and it took right off rather than cranking and cranking to fill up the bowls. check to see how much gas you got in your bowl after you let it sit. you might have a small leak somewhere. cause if it runs fine after you start it then i wouldnt think it would be the mechanical.

[John Scott]

I know the old Q-jets used to do this due to leaks in main well. I agree with last two. Take it off and see where its going.