20A Fuse blows when mower engaged?

Hi
I have a Craftsman Riding Mower, model 917.274632. I made the error of reversing the cables when I jumped the battery to start it this year.
Once I realized the error and fixed the connection, the engine started. The engine however stopped as soon as I engaged the mower and I couldn't start it again.
I read some forums and found the 20A Fuse blown. I replaced it and repeated the above steps and the Fuse blew again.
I then disconnected the Clutch cable and repeated the same and the Fuse still blew. I didn't know how to move forward from her. Please help

Thanks