I found a used Toro Riding lawn mower with a 20 hp kohler motor. The mower has not been run in about a year. Prior to not using the mower it was operational and had been tuned up at a local shop. Now it will not start. Motor turns over but will not start. I changed the gas, cleaned the fuel lines, and replaced the fuel filter. Still does not start. The spark plug is new and seems to be getting spark. I suspect the problem might be in the carb. Just wanted to know if that is on the right track or if I should be checking somewhere else?

Check for spark,
Maybe put a little fuel in the carb.
If it starts ,then it's a fuel problem.
See if there's a fuel solenoid on the bottom of the carb.