Re: L111 problem
With the seat switch activated, someone on it.
Blades off - off course!
Parking brake off, lay on ground have a look at the drive belt, specially at the tensioner assembly, you'll likely see that thing rattling away. Watch your hands/fingers, don't poke anything while it's running!!!
Also make sure the person on the tractor does not press the drive pedals!
I adjusted my L118 TRACTOR by placing a few nylon washers between the rods and the assembly, greased up the link points >>> good results, eliminated moist of the racket that was going on down there.