3 days ago, started up ran rough for 2 miles then ok...low on gas, 2 days ago started up , let warm up 5 min, ran rough for 1 mile then ok...filled up with gas, 1 day ago very hard to start...would turn over ok no fire or gas? Finally started, let warm ,ran rough for 1 mile...changed oil, checked air filter, greased, changed in line fuel filter...ran ok, this am would not start...any suggestions would be greatly appreciated, Tks, Randy