Question

liquid rising in a capillary tube does not form a fountain if insufficent lenght is available .why?

Answer 1

The capillary action deals with a force that pulls the liquid along the surface of the tube. One your liquid surface reaches the top of the tube, there is no tube surface left above. So the water surface do not get any more upward force. So the water will not overflow the top of the tube.
Moreover, if the liquid stars overflowing then it violates the law if conservation of energy.