Minecarts

So I have just recently made a villager hall and went to add in my villagers and found out that some minecart mechanics have changed, I am sure this is to do with a plugin or server setting as it works in a single-player world. Minecarts are no longer being pushed by water and mobs (e.g. villagers) will not enter minecarts. I am hoping this can be fixed. Thanks,
-zom