Craftsman riding mower won't turn over
Hello all, this is my first post. I have a Craftsman riding mower about 12yrs old. we keep at the lake. It hasn't been used for about 2yrs. I tried to start it the other day and it would not turn over. I have changed the spark plug and air filter. The starter turns fine, but the engine will not turn over. I can turn the engine backwards with my hand but it will not turn forwards. When I try to start with the starter the engine will move about 3 to 5 degrees forward and that is all. But it will move a complete 360 degrees backwards. Any help/suggestions would be greatly appreciated.