# Stock fuel pressure



## OrbitOrange (Jul 5, 2010)

Typically what would the stock fuel pressure be?

I have a return style fuel pump for a 71 lemans 350, which is what my engine is from.

Im using an edelbrock intake and carb (600 to be specific). Im reading about 7 psi on my fuel guage. The problem I am having is that when I shut down the engine after a few seconds fuel begins leaking from the butterfly shaft on the passenger side of the carb like the pressure isnt bleeding off the line after shut down or something. Not sure what to do I have tried 2 brand new carbs and this happens with both of them.


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## OrbitOrange (Jul 5, 2010)

Wanted to add more information.

The fuel pump that was on the engine wasnt bad just nasty looking and since Im temporarily using it in my 70 gto I wanted a nice new one so I went to oreilleys and got a new one. The old was was a short one the new one is a longer one. Should I go back to the short one? is there a differance in pressure between the 2 differant styles?


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## geeteeohguy (Feb 2, 2008)

7psi is a bit high....the "norm" is 3 to 5 psi. If you mean that the "long" pump has a bigger pump body, it was used on AC cars and 455 cars later on and holds a bit more fuel and has a bit more capacity. No problem with that, but I think your fuel pressure is a bit high....and could be causing the needle/seat overflow and the fuel flooding you're having.


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## pontiac (Mar 6, 2011)

time to redo the shaft. At that point in the carb, there is no fuel pressure, there is manifold vacuum and the slight pressure from the height of the fuel in the bowl. When running, it is under vacuum, but the leak becomes apparent when engine is off.


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## OrbitOrange (Jul 5, 2010)

Redo the shaft? On 2 brand new carbs?

I just thought that maybe the shorter canister pumps were for 2 barrel carbs thus less pressure and the deeper canister pumps for 4 barrel thus more pressure. But the deeper canister as a type of resivoir for more supply to make up for the use of an Air conditioner makes sense.


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## dimitri (Feb 13, 2009)

geeteeohguy said:


> 7psi is a bit high....the "norm" is 3 to 5 psi. If you mean that the "long" pump has a bigger pump body, it was used on AC cars and 455 cars later on and holds a bit more fuel and has a bit more capacity. No problem with that, but I think your fuel pressure is a bit high....and could be causing the needle/seat overflow and the fuel flooding you're having.


:agree:agree

Your float level sounds high.


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## Instg8ter (Sep 28, 2010)

Edelbrock carbs state that they should have no more than 5 psi pressure at the carb you can use an inline pressure regulator to control the over pressure.


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## OrbitOrange (Jul 5, 2010)

Instg8ter said:


> Edelbrock carbs state that they should have no more than 5 psi pressure at the carb you can use an inline pressure regulator to control the over pressure.


Thats exactly what I did yesterday morning and that fixed the problem no more leaky carburetor! Now to have my exhaust put on Turesday. Im excited!!!


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