I am a Christian and can't stop masturbating?

I have already accepted our lord Jesus Christ as our only way of life, he is my mediator and savior. I am a very devoted christian, and pray every morning that God through Jesus give me the Holy Spirit to guide me through the day and I leave my sin of masturbation in his hands. When I'm alone I start to get urges, and ask our heavenly father to take away these temptations, but I still masturbate. Please Help