• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Drain back

Roger63

Well-Known Member
Local time
1:50 PM
Joined
Aug 7, 2013
Messages
5,629
Reaction score
11,103
Location
Skiatook ok
So I'm trying to tie up my loose ends on my 440 install. One of my problems is that after sitting for a day it takes forever to get fuel up to the carb. I have a new mechanical fuel pump,new carb and fuel lines. Any suggestions?
 
It's probably not drain back but fuel evaporation. Edelbrock/Carter carb? They seem to be worse for it. Many have installed a small electric pump to charge up the fuel system after setting a few days
 
Install a check valve in the line, I had the same issue with my 70 Challenger (440) because it would sit a lot (still does) but I changed it to EFI which solves this issue due to the electric fuel pump.

The other option is to install an electric fuel pump in the rear that will allow you to prime the system. Just make sure its a flow through or allows flow through if you are not going to run it all the time.
 
It's probably not drain back but fuel evaporation. Edelbrock/Carter carb? They seem to be worse for it. Many have installed a small electric pump to charge up the fuel system after setting a few days
Yes edelbrock carb
 
Install a check valve in the line, I had the same issue with my 70 Challenger (440) because it would sit a lot (still does) but I changed it to EFI which solves this issue due to the electric fuel pump.

The other option is to install an electric fuel pump in the rear that will allow you to prime the system. Just make sure its a flow through or allows flow through if you are not going to run it all the time.
Where do install the check valve? Close to the carb?
 
Also won't hurt to look for evidence of any leaks. Check it right after shutting down because the gas evaporates pretty quick and won't leave drips or puddles for very long.
 
That's where I buy all my gas, just how well do you know skiatook?
Not at all, but you have your town listed so I looked it up on the link I posted. I do this when I go on road trips so I can get the benefits of ethanol free fuel: better mileage, more power, engine runs cooler because it’s not lean, easier hot starts.
 
Take your car out for a brisk run to operating temp and when you shut it off you can usually hear the gas boiling in the carb. Ethanol boils at 173°
 
Last edited:
1/2" thick phenolic spacer fixed mine of that problem but I didn't have hood clearance issues. I drive mine way to much to be looking for ethenol free gas.
 
So I'm trying to tie up my loose ends on my 440 install. One of my problems is that after sitting for a day it takes forever to get fuel up to the carb. I have a new mechanical fuel pump,new carb and fuel lines. Any suggestions?
Are you positive that fuel does not come out of the discharge nozzles before a cold start within 24 hours, or could it be an incorrect choke setting and not fully closing? Also, verify that your fuel pump pushrod is 3.22" or as close as possible.
 
Last edited:
Are you positive that fuel does not come out of the discharge nozzles before a cold start within 24 hours, or could it be an incorrect choke setting and not fully closing? Also, verify that your fuel pump pushrod is 3.22" or as close as possible.
Yes positive, after the 1st time that was the 1st thing I checked.
 
Yes positive, after the 1st time that was the 1st thing I checked.
Something doesn't seem right. I had my car at a show yesterday and had to get gas on the way with 10% ethanol. Got home over 24 hours ago and just checked it. Pumped it 5 times and got gas every time. Are your float levels set to specs?
 
Something doesn't seem right. I had my car at a show yesterday and had to get gas on the way with 10% ethanol. Got home over 24 hours ago and just checked it. Pumped it 5 times and got gas every time. Are your float levels set to specs?
Brand new carb, it done this on the motor I took our just not as bad.
 
Something doesn't seem right. I had my car at a show yesterday and had to get gas on the way with 10% ethanol. Got home over 24 hours ago and just checked it. Pumped it 5 times and got gas every time. Are your float levels set to specs?
No 2 motors are identical, simple things like a thicker base gasket, air flow under the hood, thermostat rating, whether or not the heat riders were blocked off in the intake, brand of carburator, type of intake, etc all play a factor.

If it's fuel boiling out of the carburetor the best thing you can do is insulate the carburetor from the source.. the intake.
 
Auto Transport Service
Back
Top