To start off I am very new to repair and maintenance on lawnmowers. I am working for someone and using there lawnmower. The mower is a John Deere 4 Cycle engine and the manual is lost. I changed the oil the other day for the mower with SAE 30 Motor Oil and it did not work. I tried to start it many times but would not stay running for more than 60 seconds. I then realized I did not put enough oil in and filled the oil to the correct amount and tried to start it again a little later. It would not start at all and it sounded like it wasn't sparking but I'm not sure. I later found out I could have easily ruined the spark plug by trying to start it and running it without enough oil. I am unsure of what I should do now. I do not have the tools to test the spark plug to see if it sparks. Help would be greatly appreciated.