Is he smelly all the time or just when he come inside after being outdoors? Could be what he is eating? Kai doesn't usually smell but there are times when he does. I don't know why, I figure its the food or he needs a good brushing.
Is it his body or his feet? Dogs really only sweat through their paw pads, so those tend to be stinky. You can soak them in ACV and water for 5 minutes a day to get rid of the stink. You can also put it in a spray bottle and spritz him down.