[mscat]

I also agree that the smell could be coming from his mouth, it is always important to have a new dog taken to the vet as soon as possible. Maybe the orginal owners were not feeding this dog well, and that could be contributing to the smell. Their are a lot of very good pet shampoos and conditioners on the market, be sure to always brush and comb him after his bath and blow dry him on low heat without holding the dryer close to his body.
Where did you adopt this dog? Did you ask the orginal owners about this dogs medical history? are about any problem behaviors? Is he fixed or spayed? or up to date with vaccines? The smell could also be from a infection coming from his ears. It is very important to get him to the vet as soon as possible.
I hope this dog is a good experience for you, and easier for you to care for since he is not a puppy, but will still require a great amount of care and love from you. Make sure you keep this one safe as possible, and know what he is doing at all times. Not sure how you lost your first pup, but it did not look like you were very happy with the first one you had.