If you haven't got a manual, I'm sure one of these fine members can show where you'll find a digital version, but after consulting mine..... early motors have a single plug on the bottom of the engine; that's the oil tank drain. There's also one fore and one aft that are sump drains. Later engines have all three on the bottom, but the tank drain is still in the same place, left side bottom, just inboard of the second pan perimeter bolt from the front. And yes, it should empty the tank. I'm thinking you just emptied the sump? How much oil came oil he asked? You said all three?? Somethings not right.
The manual is marked wrong??