Does he lick himself? Often, doggy smell can be related to saliva. That rather brings you to dental health and diet. If you don't brush his teeth daily, that's something to consider. Or, if you can't face daily, then give him raw bones (never cooked) to chew on. It won't completely replace tooth brushing, but it does help to clean and let you away with brushing a bit less frequently.
Another thing to look at overall is diet. Without having the faintest idea what you feed, I'll remark that doggy smell often goes hand in hand with low quality diet. Changing to raw, homecooked or a very high grade kibble (in that order of preference) can make a world of difference.