ORIGINAL: Rcpilet
If the carb leak is so bad that he resorts to using silicone to seal the carb--it will be hard to get a good seal because of the residual oil. Silicone doesn't stick to oil. It will form and flow around the oil, but it won't stick to the metal beneath the oil.
Chris and Barry,
This is the reason I specified methanol, or another solvent;
not glow fuel.
It is also possible to use rubbing alcohol, or those injection swabs saturated with Iso-Propyl alcohol.
It smells awful, but it would get the aluminium crankcase very clean and very dry.
The RTV silicone will stick tenaciously to this surface.