Here is a quote from the Corvair Forum concerning the water decarboning.
"Posted by Ken Schifftner on August 16, 2002 at 13:26:45.
In Reply to: Re: Water in the carb debate posted by Matt N. on August 16, 2002 at 10:11:54.
I certainly agree with Matt.
We've done the water cleaning trick a couple or three times at the Coyote Club meetings. We even came up with a fogger nozzle that blows a mist into the carburetors (if the idea of pouring water slowly into them makes you squeamish). You don't want to hydraulically lock the engine with water.
What actually happens, I'm told, is that CO (carbon monoxide) is produced more than any blasts of steam. This technique is also used (sometimes with ammonia addition) on incinerators to help burn out carbon. Since extra CO is produced, you should certainly do this outdoors.
It does work.
An old mechanic who lived near me in NJ when I was growing up would start every tuneup with, first, an inspection of the plugs, then he'd replace them and do the decarbon ritual."