[WORKAROUND] How to time pause in update (yield)

what I want to do is heaving a yield in middle of void update () because it's very important that the code is executed each frame

but in end I want to have infinitive loop and need yield witch doesn't work than I tried bypassing it with function and still doesn't work it just doesn't call that function

EDIT: http://www.blog.silentkraken.com/2010/01/23/coroutines-in-unity3d-c-version/

I've added the the corutine but still doesn't work in mean time when this Q was waiting alone I've figured out how to access variables in other scripts was wandering why once I could and now I cant

strange how I can access gameobject with accessing the script;

I bypassed the wait for time with 3 more if statements if anyone knows the answer how to have wait for seconds in void Update () I would be happy to hear it

what I want working(C#):

 void Start (){
     /*need for something*/
 }
 
 IEnumerator Wait3Sec (){
     yield return new WaitForSeconds(3.0f);
 }
 
 void Update () {
     while (true){
         StartCoroutine(Wait3Sec());
     }
 }

my full code (C#):

 using UnityEngine;
 using System.Collections;
 
 public class CraftPosition : MonoBehaviour {
     public bool Building = true ;
     public bool Builded = true ;
     public float Smooth = 1 ;
     public float Distance = 3 ;
     public float TimeTillBuilded = 3;
     public Create Script ;
     
     private GameObject Player ;
     private float ObjectX ;
     private float ObjectY ;
     private float ObjectZ ;
     private float time ;
     private float time1 ;
     private Vector3 position ;
     void Start () {
         Player = GameObject.Find("Camera") ;
         Script = Player.GetComponent("Create") as Create ;
 
     }
     
     
     void Update () {
         //snap position in to player's controll
         if (Building){
             Player = GameObject.Find("Camera") ;
             transform.position = Vector3.Lerp (transform.position , Player.transform.position + Player.transform.forward * Distance , Time.deltaTime * Smooth);
         
             // change craft object to gravity and snap out of player's controll
             if (Input.GetKeyDown(KeyCode.Mouse0)){
                 transform.rigidbody.useGravity = true ;
                 Building = false ;
             }
             // player's controll the distance
             if (Input.GetAxis("Mouse ScrollWheel") > 0) {Distance += 0.5f;}
             if (Input.GetAxis("Mouse ScrollWheel") < 0) {Distance -= 0.5f;}
             
             // player's controll the rotation
             if (Input.GetKey(KeyCode.Mouse1)) {
                 ObjectX = (Input.GetAxis("Mouse X"));
                 ObjectY = (Input.GetAxis("Mouse Y"));
                 if (Input.GetKey(KeyCode.Delete)){ObjectZ = 1 ;}
                 if (Input.GetKey(KeyCode.PageDown)){ObjectZ = -1 ;}
                 transform.Rotate (ObjectY,ObjectX,ObjectZ,Space.World);
             }
         }
 
 
 
         // after 3 sec make object to kinematic so it's builded object
         if (Building == false){
             if (Builded){
                 position = transform.position ;
                 time = Time.time ;
                 Builded = false ;
             }
                 time1 = Time.time;
             // if it's not stationary start at beginning with new position
             if (position != transform.position){Builded = true ;}
             // if it's X seconds stationary freeze building object
             if (((time1 - time) > TimeTillBuilded) && position == transform.position){
                 transform.rigidbody.isKinematic = true ;
                 Script.NotBuilding = true ;
                 this.enabled = false ;
             }
         }
     }
 }