You get engine damage from lack of lubrication
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.
it is gas only no oil is added to the gas
Not really sure what you're getting at. If your lawnmower engine is a 2-stroke then you need a mixture of oil and gas to run it.
When you overfill oil in a lawnmower it will smoke when you tip it sideways while mowing,it has no harm
If the wrong oil is used in a lawnmower, do not start it. Simply drain the oil as completely as possible and fill with the proper oil.
to put the oil in the lawnmower's crankcase would be fine, so long as it is an appropriate viscosity.
If your lawnmower is a 2 stroke mixing oil in the gas is what it needs to run right. If your lawnmower is a 4 stroke mixing oil in the gas fouls the plug and makes it not run.
Drain the oil and gas out of the crankcase and put oil back it should be OK
this should be a straight gas application......4clcle, right? You shouldn't have to mix oil in the gas.
You can cut down trees with your lawnmower. Warning: Do not actually try to cut down a tree with your lawnmower. More than likely, the gas in the chainsaw is mixed with 2-cycle oil. If your mower also has a 2-cycle engine, nothing will happen. If your mower has a 4-cycle engine, the engine will probably smoke (bluish in color) until the oil is burnt up during combustion. At worst, the oil in the 2-cycle oil/gas mixture will foul up the spark plug and you will probably have to clean it pretty often until the oil is burnt up.
If the lawnmower has two compartments one for gas and the other for the oil, then put gas in the gas and a 30w type oil in the oil compartment. Simple as that. If you have an engine with only one compartment then you'll need to check on the manufacturers suggestions which is usually 40:1 or something close.
40:1