I have a weedeater riding mower that I just bought second hand. I replaced the fan belt when I first got it and just repaired the right rear tire. Since putting the tire back on I have not been able to get the mower to move in any gear. The fan belt looks loose, but the drive shaft is turning. I have looked for any debris stuck and there is none and all pulley's turn freely by hand. Any ideas?

Engine Stalls When Mower Deck Activated