got it fixed...took the carb off from the troubled cylinder and found a small piece of what looked like gasket material in the orifice on the float bowl.
motor running on three cylinders. Plugs are new and have spark. spark jumps 7/16 with the spark tester. Compression is good. I rebuilt the carbs last year but it ran good for a while after that. Is there an easy way to check if fuel is getting to cylinder.
