Small Engines (Lawn Mowers, etc.): rx75 john deere, fuel tank cap, vapor lock

Question
I bought a used john Deere rx75. The previous owner said it sat in garage for about a year.
It mows great, starts easily, but shuts off randomly about 30 min into the job. Sometimes, it starts right back up and sometimes it  requires me to sit for 10-15 min before it will start up again.  People are mentioning needing a new battery, some are mentioning vapor  lock, some are talking  about a little gasket ring at bottom of engine...I am totally confused. Do you have any suggestions?

Answer
audra
a lot of times when the engine quits after running is the coil breaks down and then after cooling off it will restart again,and run till it gets hot. Also the fuel tank cap may be causing the problem but I don't think so what you can try is loosen the fuel tank cap and try that. If this still persists you would need a spark plug tester they are fairly cheap and a good tool for the DIY run the mower normally until it gets hot and shuts down pull the spark plug boot and install the Spark plug tester then try to crank if you see no spark at all then it is the coil.