I believe aluminum alloy carb parts generally have a surface protection
treatment, and when the "coating" is compromised, the underlying metal is
unprotected, and rapidly attacked by oxidation and any other compound that
gets near it.

You may be able to strip the white "blooming" away, but without the
protective skin, I think it's likely to resume blooming/corroding as it gets
exposed to other materials.. a little water in the gasoline, etc.

If you're adventurous, try blasting the area (low air pressure) with table
salt or other granular material that will dissolve quickly for cleaning
after blasting.

I forget what causes the white crystallization of aluminum.. a salt maybe
(so salt may be a bad choice), and if treated with a base, the white
corrosion may be able to be cleaned away effectively, but that doesn't mean
it will be stopped.
I've seen these same spots on chemistry lab stands, bases/parts, but those
parts can often be repainted after the corrosion is cleaned away.

I think there is probably a method for restoring antique carb parts'
protective layer, so possibly, old car enthusiasts may have an answer.

I had an electric motor at the back of a bench, which sat in contact with a
sandstone wall for about 2 years (below grade and the wall had been coated
with unknown products).
The end bell of the motor was an aluminum alloy, and a considerable area of
that end bell rotted/corroded away by the time I discovered it.
The hole was large enough that a golf ball could've passed thru it, so
compounds in the stone or the flaky coatings rotted the aluminum. White,
crystalline residue around the hole.

--
WB
..........


"Gerry" wrote in message
...

I do not want to brush it off. There are too many areas where even a
tiny brush will not reach and still be stiff enough to remove the
corrosion. This is why I ask for a way to CHEMICALLY remove the
corrosion. Looking for a proper dip or soak. Thus far I have tried
Berryman carb soak. Got the carb clean but did not touch the
corrosion. Next I tried vinegar-no good. Then CLR-still no good. Next
was lemon juice-a small improvement. Then came soda/cola-with about
the same results as lemon. Muriatic was way to aggressive on the base
metal to use for long. Next on my list is phosphoric acid, and then
alkaseltzer or Polident. The whole object is to get a good, even
finish and dip or media blasting is the only way I know of being
consistent. I really don't want to have to blast a carbs internal
parts with any kind of grit for fear of plugging tiny orifices up. My
gut tells me a mild acid is the way to go because I suspect the
corrosion itself is probably basic. I think it's a matter of finding
the right one/ones. Surely with all the knowledge in this group
someone else has been here before