Fuel Overload Fresh Engine Build

[Bob Nossal]

I have an Edelbrock AVS on my freshly built 440. Edelbrock specifies a regulator if pressure exceeds 6.5 psi. I rifled through my files and found that the Carter mechanical pump I have produces 8.5 psi.

Several people I spoke to thought it was odd that a regulator would be required with this carb.

I am asking you folks because I fired it up again after break-in and noticed it was rich. I thought now the tuning begins. Then, I noticed fuel pushing past the accelerator pump shaft. Not good. Now it seems Edelbrock is correct.

Any thoughts on this?

 

[steve340]

Edelbrock made the carb so they should know about the fuel pressure requirement I suppose.
In any case a consistent 5.5 - 6.5 of fuel pressure is fine on most street cars.

 

[RemCharger]

. I rifled through my files and found that the Carter mechanical pump I have produces 8.5

Any thoughts on this?

All that tells you, is what the spec " should be".
A gauge tells you " what it actually is".

First thing I would do is give that old carter carb a good whack with a hammer, see if it straightens out

 

[steve340]

Something you may want to check first is are the float levels actually set right?

 

[sam dupont]

Might be a. good time to change the oil. These work, 1-6 pounds. I would rather source a proper pressure pump than add parts and fittings to a fuel system. Less chance of a leak someday.

 

[Geoff 2]

You don't need a regulator. What you DO need is to remove the carb top & check float level & for any debris under the left side needle & seat [ flooding at pump plunger ]. You have a flooding problem.

Carter designed these carbs [ in the float/needle & seat/inlet area ] to work with up to 10 psi of fuel pressure & the Edel is an exact copy in this area. See below. The 5.5 psi that Edel refers to is for the datum jetting. Higher fuel pressure richens jetting [ slightly ] & vice versa.

Because you are at 8.5 psi line pressure, I would set floats at 1/2" [ not 7/16" ].

 

[turbine68rt]

I can only speak from personal experience, but when it comes to a stock setup there was no need to use a mechanical pump higher than about 5.5-6 psi. I used to regularly race mine in the early '90's and often had e.t.'s equal to, or quicker than when these cars were new (referencing magazine test times). This was using the original 4429 carb and factory installed 5/16 fuel line. Never experienced any fuel starvation even at the top end.

 

[lewtot184]

The Carter 6903 pump is a simpler solution. A return line can help regulate pressure. I don't know of any carb that will take 8 or 9psi. Check your float level and make sure you don't have a " soggy " float.

 

[Bob Nossal]

The Carter 6903 pump is a simpler solution. A return line can help regulate pressure. I don't know of any carb that will take 8 or 9psi. Check your float level and make sure you don't have a " soggy " float.

No regulator. Just the pump.

 

[lewtot184]

No regulator. Just the pump.

6903 doesn't need a regulator.

 

[Bob Nossal]

6903 doesn't need a regulator.

Thanks. I asked because the spec shows it still exceeds the Edelbrock recommendation of 6.0 psi.

 

[RemCharger]

Thanks. I asked because the spec shows it still exceeds the Edelbrock recommendation of 6.0 psi.

The spec shows what the manufacturer believes the output should be.
A gauge shows you what it actually is.

 

[lewtot184]

Thanks. I asked because the spec shows it still exceeds the Edelbrock recommendation of 6.0 psi.

I use 6903 pumps. They're 5 to 6psi.