1994 Isuzu Amigo (2.6L w/ AC)

I just purchased a 1994 Amigo (2.6L) that was smoking quite a lot. It was water and antifreeze. I went to my mechanic to have the problem repaired. He sent the head to the machine shop and installed a new water pump. He says the timing belt was in excellent condition.

The day I went to pick it up it was smoking big time after the head job was completed. I came back the next day and it was not smoking. He said the muffler & catalitic had water in it and he had to "flush the exhaust system with water thus I had to run it two days."

Ten minutes later after he closed his shop for the long Christmas vacation my car started smoking thru the tail pipe like it had before if not worse with drops of water coming out the tail pipe.

My question is this possible that there is still water coming out the pipe or did the machine shop do a poor service on the head? Anything else that could be happening that I could suggest to the mechanic? I do have a one year warranty on the job!

Gabriel