You definitely MUST let the silicone dry at least overnight before assembly and use a generous amount. Clean the engine and the water pump off really well before starting over again and apply LIBERALLY with a nice fat bead.
Sorry it's giving you trouble Jimbo, this sort of thing is frustrating as heck sometimes.
06 Rubi with some sort of double ended, chrome knobbed, cross threaded, infinitely adjustable, frequently breakable, worn out flammywhammers zip tied onto it.
It used to be a jeep thing... til that sh!t broke!