Holley 4412 leaking

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Mar 3, 2009 | 07:18 PM

jsutton

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Holley 4412 leaking

I posted in the cooling forum about a squeal my engine has developed and while I was under the hood I noticed gas on the intake manifold. After further inspection, it looks like it's leaking from the accelerator pump diaphram. This carb is only 2 1/2 years old. The truck still runs great with no problems on acceleration or anything like as if there were a hole in the diaphram. It looks like it coming from around where it attaches, the gasket that you can see is soaked with gas. As the truck is running (idling) I noticed a drip drip drip coming from one of the screws on the diaphram cover. Is it possible that just a screw vibrated loose some? Can I just go get another 30cc diaphram and just replace it. I do not want to tear into this carb, because it is so new and the truck runs great. Thanks.
Once again this is a Holley 500 cfm 2 barrel carb on my pretty much stock 302.

Mar 5, 2009 | 12:09 AM

fmc400

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From: Austin, TX

Try tightening the screws evenly. If the problem persists, replace the diaphragm and check the cover for flatness.

Mar 5, 2009 | 08:29 AM

jsutton

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Ok thanks, I'll do that when I get home this afternoon. Also after some searching around I see that mine has the 50cc diaphram not the 30cc one.

Mar 5, 2009 | 01:41 PM

jsutton

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Well I went ahead and checked them when I went home for lunch. The screws on the diaphram where tight so I decided I'd check the float bowl screws. Good thing I did, the top ones weren't even tight at all!

and the bottom ones were pretty loose too, but not like the top ones! It's a wonder I couldn't see gas pouring out of there.

Oh and on a side note, my gremlins must be back! Because the squealing that I was investigating when I found this leak, wasn't there today when I cranked it up to test and see if it would still leak??? No squeal at all not even a hint of a sound, just nice purr of the engine???