I got carb kits just clean and freshen up the webbers on the 6 engine while it is out of the car. Well, when I opened them up I found in one float bowl some crusty yellowish white stuff. I sprayed with some carb cleaner brushed it with a tooth brush wiped it out and blew it with some air and more white crust appeared. What is this and how do I get rid of it? This stuff could obviously clog up jets, which is no good.

I also found that one of the floats is dented, like some PO droped it and steped on it, I floats though, should I be concerned about that?


TIA,
Mike D.

sounds like some evil bacteria!

I've heard that zinc-body carburetors like Webers and Solexes have a coating that can be (this is the hard part...) permanently damaged by overexposure to carb-dip (principally methylene chloride). could be that what you're seeing is the formation of zinc oxide (that white stuff used in sunscreen...) caused by exposure to the air without this protective coating. (if zinc could rust, which it can it'd be that stuff - rust is iron oxide, and zinc oxide is that stuff...) i don't believe zinc can be anodised so i don't know if another protective coating is possible.

floats need to have a certain volume - if they don't i'd replace it; they should be still available tho ...

The way to fix this permanently is to strip the carbs completely and have them chromate dipped and the surface converted. The carbs end up looking a bit army green but the crustiness will go away. A lot of aricraft places do the dipping.

Wow.
This sounds so familliar to me. My 34-PICT on my Ghia does this - and I thought it was calcium deposits setlling out of the gasoline.

But now that you mention it, my Dellortos on the 912 engine don't have this problem at all. They were always clean and shiny.

So why in god's name was this material chosen for making carbs?

Carbs are made from "pot metal". .....that's an old term, dunno what they call it now. IIRC, Zinc is part of the alloy. It is used cause it has a low melting point, it's easily cast, and is cheep.
Pure Zinc=Galvanize.

I suspect something else is going on here other than
just the loss of protective coating....whatever it is.

Electrolysis or caustic contamination are the likely culprits. Both need water to do their nasty work. Humidity in the air will sufice for a caustic.

as opposed to what ?

it's cheap, easy to mold into complex shapes, easy to machine, doesn't rust, and properly treated, doesn't corrode.

brass and bronze are expensive and heavy. aluminum and magnesium are possibilities, but i bet there's some of each of those in the 'pot metal' that makes up a carburetor body.

i'm sure contemporary fuels full of oxygen-bearing additives are doing the coatings and base metals no good.

treat 'em right and they'll do a good job for a long time. it's hard to get car makers excited about the problems, of course, because they want to sell you a new car. Porsche hasn't made a carbureted car since - what - early '73 ? (911T with Zeniths...)

i wonder what PMO is using as their carb body material these days - and what it's coated with ... certainly they're priced like they're cast platinum ...

PMOs are cast from A-356 Aluminum (per PMO website)

PMO

PMO ... nice carbs ... nice $$$




Eddie