My TimeMaster 30" has developed a random problem. The mower starts fine and will run normally and then suddenly stop. Sometimes I can start it again immediately, sometimes I need to wait a few minutes. This has happened 2 times out of 3 mowings. The second of the 3 mowings was without any issue. The mower has plenty of gas. I did just recently change the gas filter and air filter. I had no issue of this kind last year. Any thoughts?