Pooping Outside Litter Box?! HELP ME!?

My cat, Maverick, is a 1 year old male, who has been fixed. He is part maine coon, so he's a big boy! Anyways, he poops outside his litter box. He pees in it, but not poops. It's the same litter he's used since he was a kitten, nothing has changed, he gets SO SO SO much love and attention. I scoop it EVERY day, sometimes twice a day. He's such a wonderful cat, but he doesn't go poop in the BOX! And his box has NO lid, and it's big, so he can move around comfortably. I haven't taken him to the vet yet, should I? Could something be wrong? HELP ME! He poops like MAN sized poops! Could he have a medical condition? If so, PLZ PLZ help!