Fuel pump and Weber

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Alexis Chatenet
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Fuel pump and Weber

#1 Post by Alexis Chatenet »

Hi !

The previous owner of my 57 AT1 had fitted an electric fuel pump (see picture), because he said that Webers 40 IDF do not get enough fuel with the original mechanical pump.

The electric one works perfectly, but I suspect it may cause the carburetor butterfly axles (not sure about the term :? ) to leak a little bit when idling for too long.

I have the original mechanical fuel pump, so I am now looking for advice :

- should I refurbish the original pump, and remove the electric one ? (or use it as a primer pump when the car has not been driven for a while)
- should I keep the electric pump and try to find a pressure regulator ?

Any other comment or idea is welcome !

Thank you !
Alexis

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Mike Wilson
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Re: Fuel pump and Weber

#2 Post by Mike Wilson »

It may be the butterfly shafts (axles) bushings are worn out and leaking. I don't have much experience with Webers so others with more experience can lend their expertise.

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David Aronson
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Re: Fuel pump and Weber

#3 Post by David Aronson »

If your pump is 3-3.5 psi then it is not an excess fuel pressure causing the leaking. A agree with Mike, probably the shaft bushings need servicing. I have kept my original pump and use the electric pump for priming and as a redundant source.
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Martin Benade
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Re: Fuel pump and Weber

#4 Post by Martin Benade »

I’d imagine the original pump can supply enough GPH unless your car now gets quite dramatically lower fuel mileage with everything working well.
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Dick Weiss
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Re: Fuel pump and Weber

#5 Post by Dick Weiss »

It may be difficult to get the output pressure down to 2,6 to 3.0 (maximum) w/an aftermarket pressure
regulator. Meanwhile, as long as the OEM mechanical pump(s) is in good condition, they'll do the job A-OK
for years.

I don't have a choice w/my 4-cam, but having a pushrod engine presently in place, no problem using the twin
Autopulse pumps which can give the same output as the pumps mentioned above.
I only use 1 of 2 pumps altho using both are regulated to 2.6-3.0 psi w/the OEM Carrera's fuel/filter regulator.

Tom Blash
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Re: Fuel pump and Weber

#6 Post by Tom Blash »

I fitted a low pressure Facet fuel pump to my 61 S90 without a regulator. It was too much pressure for the floats and the engine kept flooding and running rich. I left it installed but with a momentary switch to fill the float bowls and rebuilt the original fuel pump. All is good now, takes 5-10 seconds to fill the bowls.

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Alexis Chatenet
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Re: Fuel pump and Weber

#7 Post by Alexis Chatenet »

Thanks a lot for your feedback !

I forgot to tell you that the carburetors are brand new from redline, the previous owner gave them to me because the ones that were on the enfine (webers already) were leaking from the shafts. And as the new one are just a little bit wet on the shafts (but it is not a real leak like it was on the old ones), I suspect the pump. I absolutely don't know the output pressure on this pump.

I will try the original pump and see if it works ok, if it does, I may fit the electric one as a primer pump.

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