It was stored for two years with gas in it... I have put in fresh gas, changed the air filter, cleaned the carb and changed the spark plug and the battery. It did crank a couple of times, but ran very rough and now it won't crank at all. It will turn over, just not enough to run.

What motor is in this unit besides 16 horse , briggs , kohler . Twin or single cylinder

I know it is a Kohler with OHV

Okay you said you cleaned the carb . Does it have fuel solenoid on the carb if so see if its clicking when key is turned on,
Try pouring a little gas in the carb and see if it starts , if so go back to the carb.
Luck