The Stovebolt Site Forums The Shop Area Engine Shop Carburetor Builders Answer This!!!!!!

I've rebuilt a few Rochester carbs over the years. Now I am buying some and rebuilding again. The last three have had a white substance in them. Mostly in the pump well and around that area in the bowl. Some times the white stuff is hardened, sometimes pasty. Soaking in the normal parts cleaner I use for carbs does not touch it!! Tried flashing in heavy duty calcium cleaner (not supposed to use on aluminum) and that did not touch it, so I don't think its calcium, it's something left over from the gas? Before I start trying vinegar, bleach, etc. I think some of you will know what the heck it is and how to desolve it. I abandoned the build of the first two, but I do not want to do that any more. these carbs have all been sitting awhile. Carb cleaner does not touch it either. thanks

Shot in the dark, but aluminum oxide is white. Maybe signs of corrosion by some nefarious means...

Lead oxide.
DG

good question, i was wondering the same thing. i rebuilt one that had the same deal. the berrymans pro carb dip did loosen mine up but i had to work it a little to get it all off. i had heard lead as well but wasn't sure.

Well I have dealt with the white deposits myself. They can be removed by soaking and elbow grease, its like removing concrete. I have always attributed it to the 10% alcohol added to the fuel here in the Midwest. If you ever seen corrosion on aluminum you will notice it is white in color and hard to remove. The alcohol tends to draw moisture and causes major corrosion issues inside carburators. It will literally ruin a carb if left in it for any period of time. Around these parts you learn very quickly to add fuel stabilizer if you leave gas in anything in the winter. Now im not bashing Ethanol. I actually own a small farm and Ethanol has a purpose. Its just hard on the old stuff that sits around for any period of time.

Most carburetor bodies are basically an alloy high in zinc content.

Over time, especially under severe conditions, the zinc will oxidize and form this white powder.

Some severe conditions:

1). Sulpher based gaskets (such as both Rochester and Carter used in the 1950's).
2). Removing the greenish goldish "chromate" protective barrier from the zinc alloy when cleaning, and not replacing it.
3). use of ethanol based fuel.

Jon.

I found out what cuts it. I tried everything under the sun. Elbow grease and scubbing will eventually get it off, BUT it will still be down in the passage ways that you can not get to. The answer is "Rust Mort" product by SEM. This desolves/neutralizes/gets rid of, the white stuff. 2-3 min soak. You are correct about the carb being made of zinc (the bowl) top and bottom are usually aluminum. the chromate coating is worn/desolved by time and cleaning solvents. Then something, probably in the gas, forms the white stuff from hell. Never buy a carb unless you examine the inside, is my motto from now on. Looks great on the outside and full of white stuff on the inside. If they are fresh off a motor it will be OK. Sitting for years........ MAY HAVE WHITE STUFF!!! If you get a white one soak 2 min in Rust Mort. Auto paint store or order from amazon.com like I did. Rust Mort is one of those rust inhibitors/eliminators/incapsulators. they don't know it removes white stuff.

Rust Mort, Jasco Metal etch are phosphoric acid made to remove rust before painting. I prefer Rust Mort, but Jasco works OK and is easier to find. Coke might work too, and you can get that at the grocery store.

Larry