Nothing other than it will not run and you will then have to remove all the water from the fuel system. It will do no real damage as long as you do not let it set this way for a long period of time.
It will overheat the engine
no, all that will happen is you might have a little extra exhaust while engine burns off oil that is in 2 stroke mix
Petrol engine? 4-stroke, no. 2-stroke, some.
No it isn't fatal, but it would smoke quite a bit, because a two stroke engine needs two stroke oil mixed in the petrol, and a four stroke just needs petrol.
One advantage of having a four stroke petrol engine is the fuel economy. A disadvantage of the engine is in the cold weather they are harder to start.
The air cooling of a 4 stroke petrol engine takes when the air flows on the engine .it takes not by radiation.
two stroke diesel engine is used in cargo ships as cross head type engines, two stroke petrol engines used in two wheelers.
nothing the 2stroke-petrol will smoke as it burns the oil which should be mixed in it
4 stroke fuel is straight petrol, it does not have oil in it! If you use it in a 2 stroke engine you will seize the motor. 2 stroke fuel has oil added to it.
high cost
Yes
4stroke engine are stronger than 2stroke cause you get to break down on a 2 stroke