NELSON - is it possible to have 4 councelors in the first presidency? During the time of David o.mckay, he has 4 councelors why?

JOEL - There is nothing in the scriptures or Church doctrine that specifies the number of counselors a president can have. He can call as many as he thinks he needs, although it is unusual to have more than two.
President McKay did have 4 counselors serving with him at one point in His presidency. The reason for the two extra counselors was because of the unprecedented growth of the Church at a time when President McKay and his First and Second Counselors were slowed by the effects of age. One of the extra counselors, Elder Dyer, was ordained an Apostle, but he was never a member of the Quorum of the Twelve. When his assignment as counselor to the President was over he continued his duties as an assistant to the Quorum of Twelve Apostles.
Thorpe B. Issacson was an assistant to the quorum of Twelve when he was called as a counselor, but was never ordained an Apostle. When he was released he also resumed his Assistant to the Twelve position.
President Spencer W. Kimball also had an extra counselor as he and his first two counselors were also slowed by age and illness.