I forgot to mention one of the leak I found (courtesy of Youtube search) Mine also did this (not a crack in the pipe but a bad seal / joint at the bottom) - this will also cause petrol to leak / drip thru the bottom outlet Fixed with some JD Weld 2 pack cold weld mix (left in sunlight all day to cure) but will see how long it lasts in petrol - JB Weld do have a petrol tank putty that may work better On the other hand, JB Weld Ultimate (says it petrol resistant) does not last in petrol - my failed attempt to use it to make a gasket - last all of a few days
That black stuff is just a silicone sealant. Can you not find an O ring to replace the seal. Had the same problem with fuel bowl and the loose brass pipe. Used epoxy and still going.
The Silicone RTV is not suitable to be used anywhere near a carb nor an engine. Save it for your rainwater downpipes. Buy some o-ring cord to make a new float bowl gasket.
For a float bowl gasket in a hurry you can cut a few appropriately cross sectioned o-rings with a razor blade and Krazy- glue the seams. (Cyanoacrylate adhesive)
re o ring - i measured it at 210mm (using a bit of wire to contour) and could only find a 200mm one at a reasonable price re RTV Silicon - yes but google and JB Weld misled me re resistant to petrol hence the warning and pics
O-ring cord is not an o-ring. You can buy any length and glue it together, usually with Cyanoacrylate adhesive as mentioned by @Alan f. I don't know how long the glue will hold when exposed to fuel. But a better stopgap solution than the silastic.
