Hi, name's Ken.
Do not put it in your mower, and yes you WILL get a LOT of smoke from using it. The mower will not run well either. Just dump it in your fuel tank of the car or truck (1/2 at a time to a full tank of fresh fuel). You will not have any problems with the perfofmance of the vehicle. Also just give it some thought: the relative ratio of oil to fuel when mixed with the fuel capacity of the tank of your vehicle is miniscule. It is a non factor, and won't hurt your emissions either.