clearinterval not working on mouseenter

Clear Interval not working in slider i have tried a lot but facing same issue is there any one can tell what is problem here and how i can get this resolved? This is a Image slider in Jquery

<script>
  $(document).ready(function() {
    var current = 2;
    var sl = $(".aa").length;
    var interval;
    function startSlider() {
      interval = setInterval(function() {
        $(".slider-wrapper").delay(2000);
        $(".slider-wrapper").animate({
          'margin-left': '-=910'
        }, 2000, function() {
          current++;
          if (current === sl) {
            current = 1;
            $(".slider-wrapper").delay(2000).animate({
              'margin-left': '0'
            }, 2000);
          }
        })
      }, 3000);
    }
    function stopSlider() {
      clearInterval(interval);
    }
    $(".slider-wrapper").on('mouseenter', stopSlider).on('mouseleave', startSlider);
    startSlider();
  });
</script>