95 mariner magnum 40hp need help and info!?

I just bought a 95 Mercury Mariner Magnum 40hp for my 15 1/2 foot glport boat. The motor is hand controlled and I would like to make it pilot powered and have no idea how and what I need to do it. The boat now has a evinrude 9.9 with omc controls. My main goal is to hook them both up and have the 9.9 as a kicker, but i first need to know how to change the Mariner over. Any info would be great. Thanks!