My cat stinks

I adopted a 8 week old kitten from a rescue place. He is a great cat but he stinks! It's like he doesn't know how to groom himself. Would this happen if he was taken from his mother too soon? I thought al this was instinct.

Well there can be many reasons..... When you say "he stinks" how do you mean?

He smells like poop. I noticed his butt is crusty ( I wont go into further details) and tonight he was on my desk and licking his paws and he really smells like poop. he didnt step in anything or just go because I was watching him.

Is this your first kitten? Kittens at this age are still learning the grooming and litter process. The mother kitty does the grooming till they catch on. Adopting a kitten so young often comes with mothering responsibilities. It is important for you to clean his booty , he will take over after he realizes how uncomfortable it is to have you do it. Also you need to watch his litter use. It is important to maintain a regular digestive system at this age.