The Mormon Jesus is not the Jesus of the Bible

Straight from the Horse's Mouth

Mormons get upset if you say they don't believe in the Jesus of Christianity. However, even their current prophet has admitted as much:

As a church, we have critics--many of them. They say we do not believe in the traditional Christ of Christianity. There is some substance to what they say. Our faith, our knowledge, is not based on ancient tradition.... Our faith, our knowledge comes of the witness of a prophet in this dispensation....Gordon B. Hinckley, Mormon Prophet, at the April 2002 General Conference

So Mormons must admit to believing in a Jesus different from what the original prophets preached. Note that the Word of God condemns any gospel other than what the apostles preached:

6 I am astonished that you are so quickly deserting the one who called you by the grace of Christ and are following a different gospel - 7 not that there really is another gospel, but there are some who are disturbing you and wanting to distort the gospel of Christ. 8 But even if we (or an angel from heaven) should preach a gospel contrary to the one we preached to you, let him be condemned to hell! 9 As we have said before, and now I say again, if any one is preaching to you a gospel contrary to what you received, let him be condemned to hell!Galatians 1:6-9

What Mormons Believe

Jesus is the physical son of God

Mormons believe that God took physical form in order to have sex with Mary and conceive a son:

The birth of the Saviour was as natural as are the births of our children; it was the result of natural action. He partook of flesh and blood - was begotten of his Father, as we were of our fathers.Brigham Young, Journal of Discourses 8:115

Christ was begotten by an Immortal Father in the same way that mortal men are begotten by mortal fathers.Mormon Doctrine, by Bruce McConkie, p. 547 (1966)

Jesus Christ is the Son of Elohim both as spiritual and bodily offspring; that is to say, Elohim is literally the Father of the spirit of Jesus Christ and also of the body in which Jesus Christ performed His mission...The Articles of Faith, James Talmage, pp. 466-467

Jesus was begotten by the Father, not the Holy Spirit

Now, remember from this time forth, and for ever, that Jesus Christ was not begotten by the Holy Ghost. I will repeat a little anecdote. I was in conversation with a certain learned professor upon this subject, when I replied, to this idea--"If the Son was begotten by the Holy Ghost, it would be very dangerous to baptize and confirm females, and give the Holy Ghost to them, lest he should beget children, to be palmed upon the Elders by the people, bringing the Elders into great difficulties."Brigham Young, Journal of Discourses 1:46

Of course, Scripture plainly teaches us that Mary was a virgin and conceived by the Holy Spirit:

34 Mary said to the angel, "How will this be, since I have not had sexual relations with a man?" 35 The angel replied, "The Holy Spirit will come upon you, and the power of the Most High will overshadow you. Therefore the child to be born will be holy; he will be called the Son of God."Luke 1:34-35

Now the birth of Jesus Christ happened this way. While his mother Mary was engaged to Joseph, but before they came together, she was found to be pregnant through the Holy Spirit.Matthew 1:18

Jesus is Michael the archangel

Now hear it, O inhabitants of the earth, Jew and Gentile, Saint and sinner! When our father Adam came into the garden of Eden, he came into it with a celestial body, and brought Eve, one of his wives, with him. He helped to make and organize this world. He is Michael, the Archangel, the Ancient of Days about whom holy men have written and spoken--He is our father and our God, and the only God with whom we have to do....Brigham Young, Journal of Discourses 1:46

Jesus' sacrifice was not enough

We believe that through the Atonement of Christ, all mankind may be saved, by obedience to the laws and ordinances of the Gospel.Brigham Young, The Articles of Faith (3) (emphasis mine)

Jesus, God, and the Holy Spirit are entirely distinct (triad, not Trinity)

References for this Mormon belief as well as thorough refutation can be found here.