Mower starts but white smoke bellows out

SOURCE: lots of smoke when I engaged stuck blades - now runs roughly

Most likely what you did was burn one or more spots on the belt. When the blades and belt stop turning, like in tall grass, the engine doesn't stop and will burn flat spots on the belt at the engine pulley. Every time the flat spot hits a pulley, it will jump and can set up a bad vibration. Run your hand around the sides of the belt or take it off and you will feel or see the thin spot(s) on it. Replace belt.

SOURCE: Engine only runs at low idle and smokes

Hi,
So now, without the blades engaged, it smokes and then dies?
In your first description it sounded like the engine was under a strain. Overfilling with oil could produce a strain, but since it ran ok until you said you engaged the blades, I would have to ask if the blades themselves, were causing the strain. Sometimes if you cut wet grass, the clippings stick to your underside of the deck and can really build up. Also some rope, wire or twine would around the spindles could creat one. Check this out...
Now, with the "smoke" issue (I'm assuming a blue smoke from burning oil) I'm inclined to think your rings aren't compressing any longer and you're burning oil. You might be in for a rebuild... I hope not.

SOURCE: Stanley mower model# 425605X692

need a new hydrostat trans. i have the same problem

SOURCE: mower smoking and running rough

Check the gas you put in, it sounds like it had water in it.

SOURCE: white smoke coming out of mower

It sounds as though you are losing power (electrical power); see if charging the battery fully allows it to run longer or if charging the battery helps.