Make sure the base is seated tight against the oring in the case and on the throat and also a common place that is hard to detect and appears to be coming from the bearing or base of the carb is the slide boot. I usually have to zip tie the boot to the carb base as after a few races, the boot starts getting oil pushed passed and it makes a mess of the engine. It doesn't seem to hurt the tune too much but it definitely leaves room for foreign debris to get into places it doesn't belong. Also check the front bearing but I would check the carb boot base and zip tie it even if it doesn't appear to leak as it may at some point. I don't ever use any type of sealant as the orings are there for a reason. Some habits die hard with people but I have never used a sealant on an oringed sealed engine. I use to on the old OS paper gasket backplates and pinchbolts but that was in like '94