Hi Allen, This mower uses 1 can of Lawn Boy oil per gallon of gasoline, so it is easy to mix. I have a two gallon gas can, so I put two cans of Lawn Boy oil in first, then add the gas. The newer models use less oil in the gas mix, but I do not know what the exact mix is.
The two stroke engines do not have an oil pan, or sump. They use the gas/oil mix for lubrication. As, I said, they last and last and are easy to maintain. The most important things are to keep the air filter clean, as the incoming air acts as a cooler. And to keep the gas/oil ratio correct.