There's likely the problem. The air traveling from the draft hole to a normal fitting stem has the same air speed. In your case it is going from the draft hole to a larger space then back into a constricted space when entering the tenon. That would create a venturi effect and probably give more force to your draw without you increasing it. That would explain the wet smoke and extra heat.I'm not sure how much this matters but the tenon on the replacement stem doesn't go all the way in, so it's a bit short.