Why Is My Lawn Mower Shooting Smoke Out The Side?

After purchasing the oil (I made sure that it is the right kind), I put in my lawnmower. I started my mower and started to shoot smoke out the side a bit so I stopped and I realized the setting too much oil. Then I switched on my mower and took much of the oil. I started again and it still smoked out the side, but finally stopped after a few seconds (30ish). I then proceeded mowing and after a while it stopped so I checked the oil and there was not enough oil. I put in more oil and then when I started again it started to shoot smoke again later. What's going on?