Got a carb with a good 3/8" of varnish in the float bowl; good and hard. Best way to remove it without destroying the carb?
Is the carb made of zinc or aluminum? Warm solution of TSP works well, but keep a close eye on it to make sure it doesn't etch or dissolve the metal. It's a medium strength alkali. Strong enough to dissolve most gunk but can also attack reactive metals if the solution is too hot.
I will share a trick taught to me by my grandfather. He and his father (my great grandfather) were farmers in Texas. I loved it when we traveled there when I was a kid, I got to play in the barn and work with them on their equipment, they taught me a lot. This is how they use to clean the parts of the fuel systems when they needed to and keep in mind they couldn’t just run down to Auto Zone. Get a large metal can (1 pound coffee can) that’s clean and fill it with water, stay with me, suspend the carb or parts in it from a coat hanger. Break out the torch with your rosebud tip and heat the water to a full boil. Boil for 5 or 10 minutes, remove from the water, blow with your air hose and hang to cool. Remember to use your eye protection. Repeat if necessary until clean this may take several times before the varnish is removed. Let your parts cool completely between attempts and make sure you do this where there is plenty of fresh air, doing this to a clean carb will release more fumes than you think. You just built yourself a mini hot tank. The heat should help to soften the varnish and the movement of the water will help to break it up. I have boiled many old Harley carbs with much success. The heat built up in the parts themselves will evaporate any residual moisture the air hose may have missed. There should not be enough heat buildup to distort anything. A simple yet inexpensive fix that should work for you. Good Luck to you.
I buy cheap lacquer thinner by the five gallon can. It dissolves lots of stuff, and won't hurt any sort of metal. If will evaporate, so if you can put the part and some thinner in a smaller closed can it might last longer.
Varnish remover or paint stripper. Remember methylene chloride? Take old paint off a dresser in five minutes. Wear gloves! Pretty sure it's banned by now.
I've got a gallon of GUNK carb and parts cleaner. It's a few years old, don't remember exactly when I bought it, but it still works great. I cleaned the Marvel Schriber carb on my Pa in laws 8N tractor this year, came out looking like new inside and out.
Not putting down other methods, but a closed container with enough acetone to cover the carb works for me. I leave it for 24+ hours. Once dry, into the bead blaster. I then blow out all passages, and follow that up with blasts from canned carb cleaner into all passages. For the next to final step, a bath in diluted phosphoric acid. Well, a series of dips, and scrubbing with a brass toothbrush. Clean and shiny. The last step is a dip in chromate to preserve finish. Check my album for results.
Used gasoline and lacquer thinner; got a good start on freeing it up. Seems like someone painted the throat area for some reason.
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