Carburetor leaks after sitting empty for long periods.

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340dartley

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I kind of already know the answer but just thought I might start a thread on it. My Holley 750 DP leaks fuel and my electric fuel pump leak fuel if I let them sit in the garage for a few weeks dry.
I went out to the garage and check the fuel in the fuel cell. It was empty so I add a couple of gallons. I turn on the fuel pump and fuel leaks out if both accelerator pump bodies onto the intake and the car runs like crap. Fuel pump starts leaking so I shut it off and go start looking at pumps online. I come back a couple hours later and kick in the fuel pump to show my wife and no leaks. I start the car and it comes to life and runs perfect. This was a couple of months ago.
Today it was the same story. Tank was empty. Added fuel car starts and leaks. Let sit and leak stopped from carb. Fuel pump still leaking but it may be time to replace that.
Have other guys experienced this?
 
sounds like the fuel is drying the seals out and when they get wet again, they swell and seal up. Now I can accept that with leather gaskets but Holley metering block gaskets are very prone to shrink when they get dry. I opened up an old 1850 and the block gaskets looked like an hour glass with all 4 sides sucked in by 1/8 inch. Use some good blue gaskets on the Holley and maybe replace the gasket on the fuel pump.
 
maybe it's just me, but the stuff I'm running always has fuel in it. I don't give my seals the opportunity to go dry and shrink
 
Old DPs are likely to leak out the bottom of the bowl where the pumps attach. The pump bodies are usually warped and in need of surfacing on a flat plate. Once that problem is solved the bowls will stay full a lot longer.
Check your oil level and condition. It is possible for the bowls to drain into the crankcase.
The fuel-pump is a separate issue.
 
The fuel pump is leaking where the power wire goes in so I think it's days are done. As far as the carburetor, I have boxes of fuel pump diaphrams and bowl gaskets. Just not sure if I should use them now or not. Will the new ones do the same?
 
I had a black one and a red one pucker on my. The blue non stick ones are pretty good but this carb was on the shelf for years. Holley Red/Blue/Black fuel pump leaking is just a bad O-ring around the motor shaft, but I believe the last time I looked into a rebuild kit, it was literally more expensive than a new red pump.
 
The pump on this car is of unknown brand. It has been on the car for 25 years or more. What is a good replacement pump that won't break the bank? The car has a mild 340 Probably around 400 horse at the crank. estimated. It still has the Carter mechanical pump on the engine.
 
I should have clarified. The Carter mechanical high output pump is not leaking. The electric pump is a pusher pump mounted next to the fuel cell outlet. The electric pump is leaking.
 
The new Holley Gerotor style is whisper quiet, and you can run an EFI inline pump too off a ford pickup frame if you have a return style regulator. Beware they pump big time so you need an equal size return.
 
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