C# coroutine not working as expected

I wanted to use a coroutine to make the player wait a little before shooting a new bullet but it never gets past the yield. Here's the code

 protected override void Start () {
         base.Start ();
         animator = GetComponent<Animator> ();
         score = GameManager.instance.playerScore;
         playerLives = GameManager.instance.playerLife;
     }
     void Update(){
         int horizontal = (int)Input.GetAxisRaw("Horizontal");
         AttemptMove (horizontal, 0);
         if (Input.GetKeyDown ("space")) {
             Vector3 shootPosition = transform.position + new Vector3 (0, 0.5f, 0);
             Instantiate (bullet, shootPosition, Quaternion.identity);
             StartCoroutine(Shoot());
         }
     }
 
     IEnumerator Shoot(){
         Debug.Log("Start");
         yield return new WaitForSeconds (shootingTimeDelay);
         Debug.Log("End");
     }
 

It never prints End. I don't get what is wrong