The question is too vague to give an accurate response, 2 cycle engines like chainsaws & snow mobiles take a 2 cycle oil / fuel mixture that varies anywhere from 8,16,32 etc to 1 however if you do an online search of the motor manufacturer & provide the information that is contained on the silver colored metal tag usually riveted near the carburetor on the rear side of the block they can tell you the exact weight (10w30) & quantity to maximize the engines lifespan
0.6 litres
to put the oil in the lawnmower's crankcase would be fine, so long as it is an appropriate viscosity.
The engine floods and you have to wait for the lawnmower to drain before you start it up again or it might start smoking.
SAE 10w30 weight synthetic oil.
To much oil. or the valve stem is loose and its leaking oil
Drain the oil and gas out of the crankcase and put oil back it should be OK
You get engine damage from lack of lubrication
Drain the oil and catch it in a clean container if you intend on reusing the same oil . Then replace the plug and place the correct amount of oil in the motor.
Yes 10w30 is a good oil for snowblower or lawnmower.
Normally about 20 ounces.
STOP! Read the instruction manual or telephone the manufacturer that sold you the mower and get the specs regarding the type and amount of oil. Too much oil can cause damage and oil leaks, don't guess, observe the marks on the dipstick after adding oil.
Apparently you didn't crank it up. You are still here. Nothing except it may clean out some old dirty oil. Remove the gas and the oil and discard same. Refill the oil section and refill the gas tank. Don't do that again.