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I have a 78 El Camino that has an Edelbrock 1405 on it. Ever since I bought it, it won't start if I let it sit for a day. Gas seems to drain out of it. I took apart the carburetor and found a hole at the back of one of the gas float chambers that doesn't seem right. Is that hole supposed to be there, or could that be why the car is having problems starting? This is my first attempt at mechanics so I'm not quite sure.Attachment 64322
Your photo shows the accelerator pump well, so yes, there has to be an exit on the bottom of it. The accelerator pump rubber cup moves downward and compresses the fuel in the well, which then exits the carburetor via the pump squirters into the venturis.
As far as losing fuel from the bowls over a period of time, please read this article....
Techin' In With Fletch - June 2014
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Welcome to CHR:
We're a bunch of folks who love hot rods, engines and all such things as well as helping out! The hole you're referencing is supposed to be there (see picture below). Maybe a few answers will help us help you:
1. When you say it won't start after sitting for a day - are you pulling out the choke all the way when trying to start?
2. Once you get it started and warmed up does it run well?
3. Has this carb been on the car a long time?
4. Do you have a fuel pressure regulator in the line? If so, is it set to 4-4.5 PSI?
5. Do you have a new fuel filter?
Answer these and we can talk some more. Again, welcome to CHR!
Glenn
good questions glenn .. my pinto has an edlebrock carb and will absolutely not cold start without full choke .. atfer it runs a second it will start all day .. i have not looked into the why ..
Using any ethanol in your gas?? Dried accelerator pump rubber is possible if your using E10. I am not a motor tech guru like others on here but if you don't hear the squish of a shot of gas when the linkage is pulled back before cranking I have found these to be the problem (especially with ethanol in the mix)
I bought the car back in 2002 and it has been sitting at my parents house until this year when I brought it over to mine. The carb hasn't been touched until I removed it this week. Who owned it before me 'tweaked' the entire car quite a bit and its missing lots of stock stuff. There isn't a choke lever to be found inside the cab and there isn't an electric choke installed on the carb. I did buy an electric choke recently and as soon as I get my carb back together I'm going to put it on. To get the car going, we essentially had to put some gas down the top of the carb and shut the butterfly plate by hand, then start the car to get it to go. Sometimes it worked, sometimes not. Most of the time it would turn over and shut back off. Once it gets going, it runs fairly well. If it sits overnight, the gas drains out of the bowls and nothing is in the glass filter. I installed a new fuel pump (mechanical) and filter just before moving it. There isn't a pressure regulator installed that I know of. Ever since I owned it, it has not started right (except for the day when I bought it).
I will be checking into an electric fuel pump as the article suggested though.
I'd like to see you stay away from the electric pump as you're close enough to stock that the mechanical pump that was designed for the job is really the best way to go. You can try a rebuild - but if someone has been at it without documenting what has been done you may be throwing good money after bad. If you can return the electric choke, I'd buy a new 1406 so you can start with a known good part. Unfortunately, the 1405/1406 tend to run a bit rich out of the box and I can not tell you how many times I have installed .095 jets and 073 x 047 metering rods to lean things up a bit.
Let us know how you come out,
Glenn
Underneath the accelerator pump nozzle at the carb barrels, is a small ball bearing used as a check valve, this sometimes sticks when the motor has sat for a period of time, if the ball is stuck it will not let the gas squirt into the carb.
Unless there is a cracked bowl in the carb, the gas can not leak down out of the bowls, as the jets operate by ventury (pressure drop caused by the air pulling through the carb), and the jets are channeled above the bowl. If the motor gets hot, it can evaporate the gas in the bowls, but they can not leak down unless the bowl is cracked. Seeing the glass filter draining back is not uncommon, however it is not the carb bowls siphoning, simply the carb's bowl vent allowing the gas to slowly bleed down to the pump after the motor shuts off. There should be enough fuel in the bowls (if adjusted correctly) to run the motor until the fuel pump picks up the fuel to the carb.
Normally with Edelbrock carbs if the fuel pressure is to high they leak fuel around the throttle base shafts and sometimes the top of the carb. A fuel pressure test is easy to do and will confirm the need for regulation. Keep in mind, a fuel pressure regulator is always a good idea and cheap insurance.
MHO, the accelerator pump circuit is not working properly, and you need a choke and a tune up.
