Holley Carb Questions

[cwestra]

While taking apart the front carburetor on my AAR I noticed several imbedded particles on the top side of my throttle plates.  I've had these carbs apart several times before but never noticed this so I think it is recent.  I've run the car with the air cleaner on.  Any idea what could have caused this?  Is this common?

Also, I've attached a picture of the inside of the main section where the float attaches.  There seems to be delamination taking place inside.  Has anyone else experienced this on Holley carbs (these are original carbs)?

Thanks.

[Chryco Psycho]

Alcohol is very corrosive , my guess ........
 ethanol fuels

[cudabob496]

water in gasoline, or fuel tank?

flush out fuel system maybe?

fuel filter a bad one? Not filtering or breaking down?
Air filter bad?

Did you change your fuel source recently?

Maybe the gasket shown is cheap and breaking down?

Not sure that is de-lamination. More likely a casting flaw? Cheap metering block material?

That part of carb is in vacuum. Maybe carb not sealed correctly, and needs new gaskets, as vacuum is
drawing in debris? Or air filter not sealed against carb top?

maybe use the new blue reusable gaskets?

[cwestra]

water in gasoline, or fuel tank?

flush out fuel system maybe?

fuel filter a bad one? Not filtering or breaking down?

Did you change your fuel source recently?

Maybe the gasket shown is cheap and breaking down?

Not sure that is de-lamination. More likely a casting flaw? Cheap metering block material?

  The particles seem too large to be coming from the fuel.  Can particles that size actually make it through the jets and passages?

[cudabob496]

  The particles seem too large to be coming from the fuel.  Can particles that size actually make it through the jets and passages?

jets can be a pretty big hole, but not likely.

[jimynick]

With the size and shape of those marks, it seems like they're high velocity impacts and I don't think any intake flow would carry them that fast; however, I do think that a backfire would generate the speed necessary to drive them into the throttle plates and I wonder if the old gal ever coughs when you whack it wide open? Pull one of the butterflies and stick it under the kids microscope and see what's there. If there's chunks imbedded you'll be on the path to figuring out where they came from. Just my 

[cudabob496]

With the size and shape of those marks, it seems like they're high velocity impacts and I don't think any intake flow would carry them that fast; however, I do think that a backfire would generate the speed necessary to drive them into the throttle plates and I wonder if the old gal ever coughs when you whack it wide open? Pull one of the butterflies and stick it under the kids microscope and see what's there. If there's chunks imbedded you'll be on the path to figuring out where they came from. Just my 

Good point! A backfire could puke up all kinds of carbon/oil residue mixture.

[cwestra]

Thanks, guys.  Although it seldom backfires, it has done it once or twice, and that amount of abrupt force certainly could explain it.  It's odd that it's only on the front carb though.  Just curious.

[72cudamaan]

Thanks, guys.  Although it seldom backfires, it has done it once or twice, and that amount of abrupt force certainly could explain it.  It's odd that it's only on the front carb though.  Just curious.

The engine would only backfire where there is fuel.