When does an leegal pitch BECOME and illegal pitch.

[Illini_Ref]

NFHS rules.

A pitcher goes to his mouth while in contact with the rubber. I know this is a violation. However, am I correct that you may warn or eject, but it is not an illegal pitch unless the ball is delivered?(Pen. 6-2-1)

If the ball is not delivered, can an illegal pitch (or balk with runners on) be called? I know that I would call it as soon as I saw it and not wait nitl the pitch is thrown, but can you call an illegal pitch before the ball is delivered in this case under FED rules?