"Herb Eneva" wrote in message
...
I was cutting the grass with my murray riding mower with the B&S 15
hp engine and doing real good. I was in third gear when I hit an old
tree stump hard . The mower stopped and now will not move and the blades
will not turn. The engine runs fine but the pulleys for the motion belt
and the blade belt do not turn. Could this be a
broken shear pin?

Very likely.

If so how do I fix it?

You've got to find where the shear pin was, and replace it with a new one.

What else could it be?

Sometimes pulleys are bolted to a driveshaft. It's possible you could have
broken one of those bolts so that the pulley is spinning freely now. -Dave

Thanks for any advice