Leaking Holley 94

[Chilly_Dog]

Hi all. Still learning about flatheads and Holley 94s - thanks for all the great posts here and on the HAMB.

I have a 3x2 setup with Holley 94s and progressive linkage on a 59A, bored to 3 5/16, 4" Merc crank, Isky jr 400 cam. I rebuilt the carbs with kits from Vintage Speed idles and runs well. I am trying to fix a leak noticed when car is just sitting cold in garage. I spent weeks chasing potential PV issues with no luck. I finally just took off the carb body, filled up the bowl on my bench and let it sit. After a few hours, I have gas on the inside of the venturis. Looks like it is seeping from the areas where both the nozzle bar assembly and the accelerator pump discharge nozzle meet the body. Each spot has new gaskets and have been tightened down with the correct length nozzle bar clamp.

Ever seen this? Any ideas?

[scicala]

Hi Chilly Dog,

If you filled the bowl with fuel higher than the normal fuel level, it will drip from the nozzle bars. That may be what you are seeing with the carb apart. It's possible some fuel is laying on the throttle plates after the engine is shut off, and leaking through the throttle shaft holes in the base, especially if the fit is sloppy.

Sal

[Charlie ny]

Chilli,
Sal's got it....try again and fill to just over the jets.

Charlie ny

[Chilly_Dog]

Thanks guys - I was filling them about half way up. Will test and advise. Appreciate the insight and happy holidays!

[scicala]

Happy Holidays !

Sal

[Chilly_Dog]

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Thanks for the tip guys - filling the bowls with less gas was definitely the ticket. Now I'm back to my original problem - which is the carb seeps gas from those spots (areas where both the nozzle bar assembly and the accelerator pump discharge nozzle meet the body) when sitting cold in garage. It slowly works its way down the venturis to the throttle plates and eventually out the throttle shaft holes or into the manifold.

I've tried every float height recommended in various posts here and confirmed floats are good. Gone through multiple needle and seat assemblies (stainless needle, then roto-disc, now daytona). Lowered the fuel pressure (~2psi). I'm currently just working on the center carb with others blocked off. Any other ideas?

Thanks and happy (almost) new year everyone! Definitely done with 2020...

[tubman]

Sounds like leaking power valves. I could go to great lengths about this, but the simple answer is to get some new proper fitting power valves from "Charlie ny".

[scicala]

Leaking power valves will not cause the nozzles to get damp and leak. They also won't cause fuel to lay on the throttle shaft and plates. The fuel from leaking power valves goes through a vacuum hole in the base and directly into the intake manifold.
Your problem may be the small thin round gaskets that seal the nozzle bars to the bowl. Could be gaskets are bad/missing, or the clamps under the hold down screws are bent and not applying downward pressure to seal the nozzles. This is just my opinion.
Charlie ny has more experience with 94's than I do, and may have a better idea.

Sal

[Chilly_Dog]

Thanks tubman - I've gone down the PV road. I thought that was the problem, as the base in that vacuum chamber was wet, but believe that was due to gas coming down the venturis, and eventually wetting out the gasket. Have tested a couple of PVs. They each have radius machined off, new gasket and aren't leaking in bench test.

Thanks Sal - I've confirmed the little gaskets are in place and swapped them out a couple times. Have tried a couple different nozzle bar clamps with same result. I'll piddle with them some more!

Appreciate the ideas!!!