Topic: Carb Cleaning Chemistry

[ben.cb500]

Ive soaked a set of Keihin carbs in a few different solutions and all result in a white powder being left behind on the surface...i suspect this is a chemistry issue
..

Can someone tell me whats happening and a good solution solution?

[harisuluv]

I know of this.  This is part of the reason why if I have a really bad set of carbs to clean I always treat it with chemicals first, let it completely dry, then soda blast it.  Otherwise you will be plagued by some amount of that residue. 

You raise an interesting question though, the catalyst seems to be water, so perhaps it is minerals in the water, or residual chemicals/cleaning agents used in the soak--who knows.  Waiting for someone to chime in with an answer.

[ben.cb500]

...is there zinc in the carb body makeup?...residue looks like what you find in sacrificial zinc anodes on boats

[750K]

What have you been soaking them in, a bit more info would be helpfull? Have cleaned a few sets of carbs, never had any residue issues. When aluminum corrodes it leaves a whiteish residue, road salt does this to aluminum rims in the winter.

[harisuluv]

Carbs aren't aluminum though

[lucky]

Carbs aren't aluminum though

They are a combination of aluminum and zinc.
High zinc content.
The white powder is aluminum hydrochlorides. Corrosion.

If you take a TIG torch and strike an arc on it, the plasma around the torch tungsten glows green. They make a special filler rod for this metal.
Many weed eater engine cases use this metal.

If the aluminum being welded glows blue or red in does not have a high zinc content and can be repaired with 4043 filler wire.

[ben.cb500]

first soak was pine sol with a bit of water....

second soak was dawn dish soap and water....

both resulted in the white powdery residue, even the bowls which i dont think are the same metal as the body developed the white dusty residue, only in little globs instead...very strange.

Is it a Base or Acid or Alkaline thing? I dont know chemistry....but me thinks its a thing

[lucky]

Most carb castings are Zamac 3.

12% aluminum and zink.
Aluminum   
primary alloying constituent

Copper   
increase strength and hardness
improves corrosion resistance

Nickel   
improves impact resistance

Magnesium   
prevents intergranular corrosion
makes aluminum alloys easier to cast

I cannot find exact percentages probably because it is a propietairy metal.

[lucky]

Carbs aren't aluminum though

They have some aluminum content.

[05c50]

Try using distilled water instead of tap water. It did the trick for me, no residue.

.............Paul

[tmac]

Simple green and hot tap water got my carbs looking like new. A welders tip cleaner is a big help as well.

[trueblue]

DON'T USE A WELDERS TIP CLEANER.  They will ream the jets and make them oversize.  I don't know why people insist on using household chemicals to clean their carbs, they aren't the right tool for the job.  The best thing I have come across is acetone, it disolves the varnish in seconds with very little effort, I had a set of CV carbs off a scewsloosy that was stored correctly, on its side in long grass storage, under the blue roofed shed with fuel in the carbs.  The butterfies on 2 were stuck with varnish, I poured acetone onto the butterflies and within 30 seconds they were free.  A small drop of oil and they are sweet.  Another bonus with the acetone, it won't hurt your carb bodies, just keep it away from the rubbers in the carbs.

[MoMo]

I have access to a water-based parts washer that does a great job cleaning carbs or any other part.  However, it leaves that same white residue. I found that I need to immediately rinse the part after it comes out of the cleaner to eliminate the residue.  Maybe the residue you are experiencing is soap?...Larry

[750K]

If water is the common factor its most likely the culprit, the water where you are could be real hard and have lots of natural minerals in it. As 05c50 sugested, try distilled or even Demineralized water and see if that makes a differance. Pine sol or dish soap should be pretty gentle. We have really soft water where I live, not to high in minerals or added fluoride or chlorine from what I know.

[lucky]

After you clean them just spray them down with WD40 and the white aluminum chlorates will not form.