B stating that the tank fills properly and that it empties into the bowl properly and then subsequently including the fact that the toilet does flush when you pour water directly into the bowl leads me to one cause: It sounds as though you may have a water conserving toilet. In some cases these types of toilets may be environmentally correct but unable to function properly. By that I mean that in some cases there is not enough water capacity in the tank that, when flushed, will create sufficient pressure head in the bowl and, in turn, create the siphon effect that should flush the bowl.
If you have one of the low-profile, low capacity tanks then your problem may be, in your particular situation, that it doesn’t have sufficient water capacity in the tank to cause the bowl to flush.
If you do not have this type of toilet you might post that information as well. The more detail you provide about the problem the easier it is to analize.