enable/disbale particle system in 5.3.2

Hey all! So I have been after this for an hour now and I've tried using the Unity API but for some reason that doesn't work. Just trying to get my particle system to turn on when an enemy enters my trigger.

using UnityEngine; using System.Collections;

public class Turret2ai : MonoBehaviour { public float rotSpeed; public float spawnWait; public bool doneWaiting; public ParticleSystem fire;

 // Use this for initialization
 void Start()
 {
     doneWaiting = true;
     //myRigidbody = gameObject.AddComponent<Rigidbody>();
     // myRigidbody.constraints = RigidbodyConstraints.FreezePosition;
 }

 // Update is called once per frame
 void Update()
 {
 }
 void OnTriggerStay(Collider other)
 {
     if (other.gameObject.tag == "Enemy")
     {
         Quaternion rotation = Quaternion.LookRotation(other.transform.position - transform.position);
         transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * rotSpeed);
         fire.emission.enabled = true;
         if (doneWaiting)
         {
             StartCoroutine(Shooting());
             other.GetComponent<EnemyHealth>().currentHealth -= 4;
         }
     }
     else
     {
         fire.emission.enabled = false;
     }
     }
 IEnumerator Shooting()
 {
     doneWaiting = false;
     yield return new WaitForSeconds(spawnWait);
     doneWaiting = true;
 }

}

(i have also tried doing the var em = fire.emission; em.enabled = true; with no results)