Leaking Holley Carb

[Steve Meltzer]

The pro who checked out my KR before the purchase, said the power valve in the primary bowl was leaking. Having replaced these and the gaskets on Corvettes (4160), I felt confident I could do this with ease....but, not so fast big boy. I replaced the PV and its gasket, carb started leaking immediately. New A-pump diaphragm (i thought it was leaking from there). No bueno. New metering block gaskets, both sides, still leaking.  If you put fuel down the venturi orifice to fill the bowl...key OUT of the ignition...fuel leaks immediately.I've never had this sort of trouble with these carbs in the past. When I pull the bowl and metering block the next time, it will be my 7th time.

Now, I'm thinkin' that this is a carb body problem...warped surface, or ?? But, and I don't see how, could a bad PV give these symptoms? (Car not running.). The car "dieseled" at shut off, when I drove it, but apparently not at the PPI, or they missed it.

What is the correct PV for a Holley double pumper, List 4174 on a KR? Does it have 2 rectangular fuel slots or multiple drilled holes? What is the best way to test a PV?
Lastly should I just replace the bowl and the metering block or, does the metering block authenticate anything and I should see if anyone can straighten it? (i think it says "6673")


thanx steve

[Lincoln tech]

I have never seen power valve leak externally they tend to leak internally causing rich mixture at idle , I assume that your leak is external ? using a small mirror to pinpoint location may help to locate the exact point of leak . Maybe power valve housing is damaged ?

[Royce Peterson]

Drew P or any carb rebuilder can fix the problem easily. If you can't work on carbs you need a professional.

[Bill Collins]

I have experienced Holley "phantom leaks" in the past that were the result of the primary throttle shaft bore in the base plate being worn to the point that the fuel leaks from the throttle bores along the shaft to the outside of the carb. Tried a bushing kit repair without satisfactory results. This fix is best left to a professional.

[98SVT - was 06GT]

Here is the list that has all the parts for each carb - lots of info on the Holley site spend some time there.

https://documents.holley.com/techlibrary_carb_numerical_listing.pdf

List of Holleys used on Fords

https://www.mustangtek.com/4150/holley4150.html

[Steve Meltzer]

thanx guys. the leak is on the right side of the carb's 1° bowl. are metering blocks dated? thanx again. s

[Bob Gaines]

thanx guys. the leak is on the right side of the carb's 1° bowl. are metering blocks dated? thanx again. s

No the metering blocks are not dated just typically have specific identification number for a particular carb

[Steve Meltzer]

thanx. steve

[JohnSlack]

Send it to Drew.

[Steve Meltzer]

I don't know with certainty, but if the metering block is warped, why not just replace it? Pretty easily done without pulling the carb, sending it out with all of the small, but undeniable risks associated? thanx steve

[Bob Gaines]

I don't know with certainty, but if the metering block is warped, why not just replace it? Pretty easily done without pulling the carb, sending it out with all of the small, but undeniable risks associated? thanx steve

FYI the specific numbered metering blocks (front and back are typically different) depending on the carb can be extremely rare so replacing one can be problematic.

[Steve Meltzer]

Bob, thanx so much...i found that out this AM! looks like i'll need to have it straightened out. s

[Peter L.]

 I wouldn't be too worried about the correct numbers for the metering blocks since the OP stated that it was a double pumper. Not the correct carb to start with anyway. If you are going to stick with this carb, the previous suggestions are all good ideas, and some a relatively easy fix.
  The C8 cobra jet carbs are $$$, but you should be able to find a reasonable C9 735cfm replacement carb.
Personally I've never had much luck with double pumpers other than in a drag application.
Try some of the previous suggestions, I'm sure one of them will do the trick.

[Lincoln tech]

Warped metering block ? I doubt that considering the thickness of the block . You need to find out where the leak is coming from and take it from there.

[Steve Meltzer]

Thanx again, guys! Peter L., not being as familiar with these carbs as I hope to be, help me to decode mine, b/c i thought it was correct.
All numbers, etc are cast/raised, not stamped/engraved.
C30F-9510-AA (is this Ford part number?)
List-4174 (double pumper, 4150 and correct from what I've read. No?)
854 (May 4, '68)

thanx again. taking notes to learn.
Newbie, steve meltzer