Paxtoned 416 won t fire with lid on when engine is cool

I've had a bit of experience with these. How do you start it? Pump once, repeatedly, or not at all? It is my experience that they are way rich when cold. Do you have stock floats in the carb? Norm had to have specially made floats, but they were because of the pressure and would collapse. I doubt it has anything to do with starting. Any other symptoms when warm and running? Stock Paxton air cleaner and hose?