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Edlebrock 1405 carb question

4K views 18 replies 10 participants last post by  3repete 
#1 ·
For some time my 350 SBC was hard to start. After setting for a day I need to crank and pump the gas peddle several seconds (10-15) before it fires.

I have replaced the fuel pump and today I thought I would try to figure it out.

I disconnected the fuel line going to the card, stuck it in a bottle and cranked the engine. After 3 seconds it spurted fuel out. Got about 4 oz in 3 pumps.

I then noticed the fuel in the hose started going down the hose (inside the hose) slowly. I am not sure if there is a bleed hole in the diaphram of the fuel pump to allow the fuel to run back into the pump.

It may also be that since there was a gap between the gushes of fuel it might just be air trapped in the fuel line.

I then removed the inlet fitting on the carb. I know in some carbs there is a inline fuel filter inside the carb. Well there was no inline filter but I did notice a small screen.

I went into my carb parts break down and it does not show this item.

Anyone know what it is and what it does?

Another question, do you think a one way valve in the supply line (after the pump) would help?
 

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#2 ·
Do you have an inline fuel pressure gauge?

I would suggest you install one, along with an inline fuel filter between the fuel pump and carb. Then start the engine and get a fuel pressure reading. That will tell you if there is a fuel pump issue or if the issue lies elsewhere.

You may need a pressure regulator too, but don't buy that until you get a good pressure reading as discussed above.

Also, there may be nothing wrong with your previous fuel pump.
 
#3 ·
Your pretty much going to have that problem with an Eddy Carb & mechanical fuel pump, at least I did. I went to a electric fuel pump an it starts much faster. I just turn the key to on for a few seconds, this fills the bowls an pressurizes the fuel line, pump the pedal a few time an then it takes about 2 to 3 cranks revolutions an it fires. Pros - It starts much quicker Cons - You'll have to tune out that constant buzzing.
 
#8 ·
Sorry, but there are probably hundreds of thousands of Ebrock carbs on the road with mechanical pumps that have no problems whatsoever.

I have a 1403 on my 62 Olds. The questionable mechanical pump works fine. The problem I have is that if the car sits for a few weeks, the fuel in the float bowls evaporates. I simply prime the bowls with a squirt bottle before starting the car when it sits for that long.

To the O.P. - is the choke hooked up and working properly?
 
#4 ·
The bowls in the carb will not drain back - cant do it. Possible your carb is too hot and gas is evaporating? Is your choke working correctly? Sitting for one day should not be a problem at all. You may need to slightly step on the throttle to set the choke all the way (manual choke on this one). You should see gas squirt out as soon as you hit the throttle too even when sitting for just 1 day (should be that way for a few weeks too).
 
#5 ·
Welcome to the world of Edelbrock performer carbs. And not all of them will do that for whatever reason as I have had a couple on other vehicles that never lost their 'prime'

My fix, a fuel pressure regulator set at about 4.5 psig, an Edelbrock fuel line and filter along with a 1" phenolic spacer seemed to prevent the carb from draining for a few days. Before you ask, that is a 1405 with the electric choke conversion.





(....and I needed to change my photo as well:D)

Dave W
 
#6 ·
Thanks,

Yes I did have some vapor locking issues and added a 1" plastic spacer between the carb and the intake, added louvers to the hood to let the heat out. That helped some, but hot start still has it issues some times.

My question is the item in the picture. Is this what feeds the main bowels????

If so then it's a joke. That would not keep my bowels full when I get on it.

Must be for something else, just wanted to get it right in my head.

I did have a elect fuel pump, (not installed) I could not live with the racket it made so I took it off (15 yrs ago)
 
#10 ·
#11 ·
I guess your right about the size.

It just made me think that since I have a 3/8 supply hose going into the carb and then go down to that small of a jet, didn't make sense to me at first. But your correct about the metering jets being small.

This may explain why during the summer months the carb would vapor lock due to the heat in the engine compartment when sitting. It would take about 10 seconds of cranking until the engine would fire.

A elect pump wuld be the ticket, but I can't stand the baning noise they make (at least the one I tried 15 yrs ago)

so you saying that that screen is the passage to allow gas to enter the bowl area.
 
#12 ·
Sorry, but there are probably hundreds of thousands of Ebrock carbs on the road with mechanical pumps that have no problems whatsoever.

So your saying GTNMUDY & I didn't have a mechanical fuel pump / Eddy Carb. starting problem? Your wrong. Mine would do same thing as his is doing. Electric fuel pump fix mine.
 
#17 ·
I don't consider two out of a hundred thousand to be particularly worrisome. More to the point, a weak pump with a bad check valve is the more likely problem. Replacing that weak mechanical pump with an electric pump certainly fixes the problem, which was a bad pump, not the fact that it was a mechanical pump.

And yes, an electric pump that allows you to prime the carb before starting the motor will always make a car easier to start.
 
#18 ·
. If the pump diaphragm is going bad, gas may be draining back into the engine oil...

. Or there may be some crud holding the pump check valves open slightly... but that still shouldn't be draining the carb., just the line... that's prolly heat evaporating the fuel or a porous carb. casting allowing gas to drain down into the engine...
.
 
#19 · (Edited)
I was noticing the draining back too. That's going to increase the time needed to cold start it when the bowl fuel has evaporated.
It's not unusual for fuel to disappear in a seldom used carburetor, many are vented to atmosphere. I wouldn't start looking for porosity or a carb leak just yet.
So, an isolated electric pump is best, a refreshed or new mechanical pump is factory style and easiest.
You really don't want the fuel backing up while the motor sits unused. Although now that it's been explained you can understand what is happening.
You can carry a can of carburetor cleaner and give the carb a shot before cold starts. That's a little easier and self contained than gasoline.
But I'd still fix the issue with fuel flowing backward first.
 
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