Flywheel turns halfway then stops on riding mower

Briggs and Stratton engine model number 33r8770007g1, Craftsman riding mower. Was mowing the lawn and flywheel fan blew up into pieces. Next time I used it it shut off made a popping noise and now the fly wheel only make a half rotation then stop. I checked the battery, selenoid, And starter. They were still good. I took the fly wheel off and changed the fly wheel key and put the fly wheel back on with a new fly will Fan but it still doesn’t work