According to Airkings :
Hello all,

I could use some advice. I was checking the blade on my newer Toro push
mower , Model 20053, and had it tilted on it's side. There was no gas in the
tank, but it had full oil. While it was on it's side (air filter up), I
rotated the blade 180 degrees to check the other cutting edge. I heard a
"gloop gloop", and promptly tilted it upright again.

When I started the mower, it was kicking out white smoke. I think some fluid
got into a chamber it wasn't supposed to be in. However, I don't know what
and where.

Can anyone tell me what happened? And what should I do now? If no one knows
for sure, I plan to change everything down to the spark plug.

The gloop gloop is probably oil. It's remotely possible that you got
some oil into the carb or cylinder head. Generally speaking, there
is no direct path between the crank case and the cylinder head,
carburetor or muffler. The only oil getting to the top of the
engine is that which seeps past the piston rings, or bypasses
the valve seals.

But you say that the smoke is white. Oil would probably be black
smoke, unless it got into the muffler, and the muffler isn't hot yet.

More likely I think is you have a little water in the gas tank,
carburetor cup, or sedimentation cup (if the motor has one). By
tilting the mower, you caused a bubble of water to get into the carb,
and the white smoke is steam.

If the motor seems to run okay, running it for a few minutes
should clear it. But before starting it again, make sure that
the mower has enough oil. If the carb cup has a drain, drain
the cup first and let it refill. Clean out the sedimentation
cup if it has one.

If you see any water, for future prevention of a repeat, it'd
probably be a good idea to completely siphon out the gas tank,
let it settle, and then carefully pour it back in leaving any
gunk/water behind. Or discard it.

[In car engines, white smoke is often water in the oil.
But that's almost never a problem with air cooled engines.]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.