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Hot!40 DFAV Weber Query

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2019/02/24 10:26:23 (permalink)

40 DFAV Weber Query

A couple of questions re the 40DFAV Weber used on the V6.
I have just purchased and installed a rebuild kit in mine and found that the car runs a bit smoother with the new kit installed. However I have an issue with the accelerator pump, it stopped working shortly after I installed the kit. There appears to be no fuel entering the pump chamber from the float bowl. I have used air and wire to try and clear the passages but all I get is a small dribble of fuel from the float chamber, which is full. I can see the fuel in the float chamber bubbling when air is applied to the hole in the pump chamber with the top of the carby removed. Got me stumped, any ideas??
Also the 40DFAV appears to have only been used on the V6 from 1970-72, then replaced by the 38DGAS. Although you can buy kits for the DFAV there doesn't appear to be any new or replacement DFAV's available for sale. Have these been discontinued does anyone know? Which is the better carby the DGAS or the DFAV? I have heard that the DFAV was used on the Ferrari V12 of the day in multiple form (*6), don't know if that's true or not though.

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    Re: 40 DFAV Weber Query 2019/02/28 00:12:58 (permalink)
    There are threads online saying that they were replaced due to over fuelling and bore washing but I don't see any signs of running too rich on my cars, and my plugs are a lot cleaner than they were when I was running a 350 Holley which was a common conversion back in the day.
    Did you soak in carby cleaner when you stripped it down, may just be some varnish build up... hopefully you didn't do any damage with the wire.
    If you are concerned about originality then changing will mean your original air cleaner wont fit, they are a different stud pattern, but if not then there is much more choice of sports filters with the 38's pattern.  Changing would also allow you to get a manual choke which may be preferable over the auto setup.  Either way unless you have a high performance engine I doubt you would notice any difference between the two.
    Before buying a new one I would have a go with carby cleaner and see what happens.
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