Kenth hit the proverbial nail on the head; some folks think it is necessary to use an 18 inch pipe wrench with a 3-foot cheater to tighten the air cleaner wing nut.
Doing so distorts (warps) the air horn.
Take a piece of flat steel, and cut an area so the float hanger will fit in the area; and place the air horn on the metal to check for warpage.
If its warped, it is not going to seal if you use 25 gaskets!
If warped, the air horn may be cautiously straightened by the use of heat (maybe 350 degrees in an ELECTRIC toaster oven) and pressure (common METAL C-clamps will do the trick).
As far as ANY sealer is concerned - DON'T!
Do it once, do it right.
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"Good carburetion is fuelish hot air".
"The most expensive carburetor is the wrong one given to you by your neighbor".
If you truly believe that "one size fits all" try walking a mile in your spouse's shoes!
Owner of The Carburetor Shop, LLC (of Missouri).
Current caretaker of the remains of Stromberg Caburetor, and custodian of the existing Carter and Kingston carburetor drawings.