I did a test by putting a teaspoon or so of water in a coffee can half full of gas. The water was visible in the bottom of the can. Then I added some Berryman's B-12 Fuel additive, The water turned into a foggy appearance and then was no longer visible. After a number of days there was still no sign of the water. I let the gas sit in the can for several months. As of now there is a very small amount of dark, thick oily substance in the bottom of the can, not sure if it will ever dry completely? B-12 is a very powerful solvent, it can melt paint and some plastics so it should dissolve deposits, like varnish, that have formed in a carburetor. I have used it for years in all sorts of applications and have never had any fuel related problems except for the time I forgot to drain the carb in one of my outboards over the winter, my fault. No affiliation with Berryman's, other brands may work as well?