Running out of fuel would be my guess. Clean carbs, change internal fuel filter if it has one, disconnect fuel line at the engine and either remove the connector or hold it open and squeeze the bulb and see if you get a goodly amount of fuel out of the hose. Engine that old may need new fuel lines if run on E10....BTDT with a 2002 in 2012. Fuel filter contents will answer that question....black specks.
