I have an old Murray 10/30 riding mower. Model # 30552x12a. Has a 10 hp Tecumseh engine. I used it recently and it started quickly and ran just fine. Today it will not start. Engine turns over just fine but will just not start. Spark plug is sparking brightly. Has gas. What could be wrong. I have no manual and Murray website says no manual available for mowers older that 2003 which this one is. Purchased in the 90s. I don't even see a fuel filter on the gas line but have not tried taking anything apart yet. Suggestions? Any help would be appreciated.