One time, I used all the Protein and carbos and everything else on a Poliwhirl ( it was the totaly powerful) and then I evolved it into a Poliwrath and all the EV of the previous Poliwhirl desapered and now that Poliwrath's stats are all so bad. I just don't get it.
The EVs stay exactly the same when your pokemon evolves. No worries. The reason the stats all jumped a bit is because Poliwhirl has different base stats than poliwrath, so those new numbers change him up a bit. You also won't see all the EV points at once. By the time you're done training him, they'll all be there, provided you trained him correctly.