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Anybody have an idea on how to stop fuel drainage from the carb?

76k5blazerr

76k5blazerr

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My blazer is my DD and it has a 350 with an edelbrock 1406 on it, electric choke has never worked and it has always taken about 10-12 seconds of cranking to get it started in the morning, hot or cold weather and even when I manually close the choke by hand it doesn't make a difference. It seems that when I go to do a cold start on it every morning the best routine to get it going is to not pump the gas first and just crank it for like 8 seconds to get the fuel pump pumping gas to the carb, then give it a couple pumps and it fires up... Is there any way to stop this fuel drain back into the tank overnight? Cause I'm also burning through a starter about every 3 months lol. Any ideas? I was thinking of converting to manual choke but will choke even help this issue?
 
The fuel pump has check valves built into it to prevent that...but today's ethanol gas evaporates much faster than the old leaded gas the truck was designed to use back 30+ years ago,and it's probably that which is causing your trouble,if in fact the carb bowl is empty when you go to start it after sitting a day or more..

An electric fuel pump will solve that,you will need to let it run a few seconds before cranking to fill the carb up though...seeing you've tried closing the choke fully,that ruled out the choke as the cause..
 
I have the Same problem with one of my 1406s on a big block in my 86 chevy. I tried adjusting the float and it helped but for some reason tge float has to be just right to prevent drain back.

Yet. I've had many 1406s work flawless with im proper floats. Maybe it is a fuel pump issue.
But i would try with thd floats 1st
 
A fuel pressure regulator between the carb and the fuel pump will stop "drain back" because a regulator is a one-way check valve. It will allow fuel to flow in only one direction, but not back the other way. Drain back of fuel happens when a mechanical fuel pump diaphram gets old and starts to wear out. They then let fuel drain back past it.
 
1-ton said:
A fuel pressure regulator between the carb and the fuel pump will stop "drain back" because a regulator is a one-way check valve. It will allow fuel to flow in only one direction, but not back the other way. Drain back of fuel happens when a mechanical fuel pump diaphram gets old and starts to wear out. They then let fuel drain back past it.
Click to expand...

Another hazard of a bad diaphragm is that fuel can leak into the crankcase and thin out the oil, resulting eventually in trashed bearings.
 
What's a decent regulator to run? And what psi? I think I'd like to try one on mine. My 1406 always is such a pain to start after sitting for a day or more.
 
(cough) TBI (cough)

All of my carb starting issues were solved by TBI. No more whanging the pedal and waving a dead chicken around the truck praying it would start. Just turn the key, and off she goes.

I know it's hassle and/or spendy, but a different take on the problem.

-- A
 
I wouldn't unless its old and you just want a new one for peace of mind,or it is showing signs of the diaphram failing (oil coming out of the vent hole in the casting),or its just not delivering enough fuel to the carb..

I tend to blame the high rate of evaporation the ethanol gasoline has for troubles like yours..it dissapears like magic in a few minutes if you spill any--years ago if you spilled leaded regular,you'd have to wipe it up ,or it would sit there quite awhile before it evaporated..let a carb sit a day or more and chances are good the fuel bowl(s) will be empty,or nearly so..and it'll take some cranking to fill them back up...

One way to tell if a "check valve" would help--if you have a rubber hose between the carb and fuel pump you can pinch shut with a vise grip or similar thing,run it for a few minutes,pinch the line shut after shutting it off,let it sit a day or two,then take it off and try starting up..if it fires right up,its not the fuel evaporating causing the trouble..
 
I fought this issue on my carbed truck for years. Happened with both edelbrock and q-jets. Was told it was the fuel pump so I tried fuel pumps, then I was told it was the little filter that goes inside the q-jet so I found one with a check valve and tried it, tried adjusting the floats etc.

Eventually I did find a permanent fix for it though, swapped in a fuel injected ls motor with an electric pump. Turn on the key and the pump builds pressure, hit the starter and it fires right off every time hot or cold:woot:
 
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