I have a Statesman 16 hp 42' cut! the thing will not move! the engine is great, startes right up and the blades will engage! I put a new belt on the drivetrain and checked the shift linkage! what else could there be?

Is the drive belt routed correctly around the idler / tension pulleys. Make sure the belt is tight when the clutch is released.

Model and serial number from the unit could help give you some other suggestions.

Best of Luck...