Agree with Jim. You need to get him listning to you tight on the lead first and then the recall will follow. He needs to know your the boss. Shouting never works and neither does too many words. And shouthing should only be used at the last resort only if hes close. Remember, dogs hear 7 times louder than us...
I take it he is pulling on the lead when he sees other dogs too?
Advise is to get him on a very short lead, holding his head up as your going past other dogs, if he looks at them or tries to pull, then keep his head high so he cant pull and perhaps a little tap on his nose on the side he is trying to pull too, so he looks back at you and the command "leave". Once he starts walking and looking at you every so often then your getting somewhere.
The move onto the sit, stay, come using food.
Hope you enjoy many years of happy dog ownership, and well done on getting a rescue, not enough people do unfortunatly. 2nd dogs can be hard work to start with as you dont know the history, but some hard work now will pay dividends in the future and he will love you for it
Woof, woof, woooof, bark to the new boy!