Definitely four or five drops is not the typical amount for filling a cart. Allyn's comment on using a paperclip is a good one. I usually use a pair of tweezers to remove the filler, the add about 11 to 12 drops in a standard 510 cart, put the filler back in with my fingers or the tweezers, add a couple more drops so that the top looks wet. Then, it is good to go and will usually last me a couple of hours or so.
But there is a lot of variance in the type of cart as to how much it will hold. 306 carts hold very very little. 510s more than twice as much. 801s hold more than twice as much again. Do you know the make/type of your ecig?