Re: Carburetor cleaning - what REALLY gets the varnish removed??
I have saved some really corroded zinc carbs that were all white inside on old cars no replacememt was available for readily,by using two things..
One is battery electrolyte..you can buy it at better auto parts stotres..
You fill a plastic bucket with it,deep enough to submerge the carb completely,after removing any brass parts like the float,needle valves,jets,etc..I tie a nylon zip tie to it for a "handle" so I can remove it easier,then leave it submerged for about 15 minutes,it will fizz like soda when you put it in the acid..after 15 minutes remove it,and rinse it off in a bucket of water with baking soda dissolved in it to neutralize the battery acid..flush it good with lots of water afterwards..it should be sparkling clean now,though some pitting may remain..
Another method I tried I read about in Hot Rod Magazine worked well to--you use a plastic bucket of water with Sani-Flush or Vanish toilet bowl cleaner,believe it or not!..same way as the battery acid,only you jusyt need water to rinse it off later..they warned not to leave it submerged TOO kong,or your carb COULD indeed "vanish"!..
For varnish ,Acetone or Laquer Thinner is hard to beat, but is pretty expensive and can be hazardous due to its voltility..Denatured Alcohol eats away pretty much anything if you soak it in it long enough..
I like Chevron "Techron" for adding to gas tanks ,I haven't tried Seafoam yet,I have heard both good and not so good results from others who have used it..(nothing "bad",some just felt it did nothing,no good or harm,and considered it a waste of money)..