am i doing this right? (renderer enable/disable)

using UnityEngine;
using System.Collections;

public class flamebreath : MonoBehaviour {

	// Use this for initialization
	void Start () {
		particleSystem.renderer.enabled = false;
	
	}
	
	// Update is called once per frame
	void Update () {
		if (Input.GetKeyDown (KeyCode.F)){
			particleSystem.renderer.enabled = true;
		}
		if (Input.GetKeyDown (KeyCode.F)){
			particleSystem.renderer.enabled = false;
		}
	
	}
}

when i press play, the renderer on the particle effect is off, but when i press “F” it doesent turn on.

i removed the line of code in “start” and yes, the fire does spawn, but when i press “F” it disables and doesent turn back on. thanks in advanced!

You are setting it to true, then back to false. Both if statements will execute.

if (Input.GetKeyDown (KeyCode.F)){
    //The line below will set enabled to the opposite value:
    particleSystem.renderer.enabled = !particleSystem.renderer.enabled;
}