We have a Sears riding lawn mower with a Kohler Command 14.5 hp motor. Ran fine until it stopped. It is now blowing oil into the carb via a short hose that appears to come from some kind of breather on the front of the motor (facing forward in the chassis). I have no experience with Kohler and need some guidance as to what this unit is and how to correct the problem. The oil is blowing in such large amounts as to kill the engine.

Replace the assembly. It's the oil breather.

Replaced breather and inspected valves with cover off and reinstalled. Same symptoms as before.

Is the oil level correct?

I would have suspected the breather assembly also kiss.