Metal on metal sound with sparks from riding mower deck

Hi Andrew:
It is quite possible that the blade is bent or the metal "grass discharge guide" has been damaged.
If you have a pickup truck handy and you can put the mower facing outward on the tailgate, this procedure is easier.
- remove the spark plug lead to ensure that the mower cannot accidentally start.
- Push the handle down so that the mower is tilted back and the underside of the cutting deck is exposed.
- slowly rotate the blade and see where it contacts (or has been contacting any metal parts.
- remove and replace the blade if it has been bent. (They can be straightened but it is not recommended)
- Use 2 hammers (one as a "dolly") to straighten or repair any bent sheet metal.
- Replace the plug lead and go cut grass.
Cheers

Turn off the mower completely and clean out beneath the deck with a mower-cleaning tool to remove any built-up grass deposits. As debris collects inside the deck, the blades can't move freely and you'll have unusual patterns or unevenness forming in your lawn as a result. The mower-cleaning tool scrapes this debris off and restores the deck to proper function.
Measure the height of the mower deck with a ruler when the mower is on flat ground. The deck should be an equal distance from the ground on all sides to ensure an even grass cut. Adjust the leveling bolts on both sides of the deck as needed to readjust the height until it's even. If the mower hits something like a rock or a large stick while mowing, it may knock the deck off balance.
Inspect the deck for any dents or warping. Use a rubber mallet to carefully straighten any dents in the deck if the deck is metal. Plastic decks generally need replacement if they crack or warp.
Remove the deck for a more thorough inspection or cleaning as needed. Remove the grass catcher and take off the pins or mounting bolts holding the deck in place. Lower it to the ground and pull it out from under the mower. Unhook the cutting blade from the underside of the deck with a wrench and set it aside.
Sand off any rust with sandpaper and use the mallet or a hammer to eliminate any remaining dents or warps.
Reinstall the deck once any corrosion or dents are fixed.
OBD Tools 365 Days Shop

Sounds like the large nut on top of the spindle may have loosened up or the splines on the pulley are chewed up. Turn the blade and try to hold the pulley on top. If the blade turns and the pulley doesnt, its one of the two things I just described.

You probably bent a blade into the deck. Its possible that something else is wedged in between the blade and deck. You can set the front wheels on a block and look under the deck. With mower off and blade disengaged, see if blades turn freely. Check each blade seprately.

You'll need to look under the deck w/ the mower not running and see why the blades aren't turning. Most likely something is bent (maybe blade) and hitting something. The smoke is probably from the belt slipping and getting hot.

sounds like he bent a blade that's when the belt went

Try replacing the blade , its most likely bent.

I would check to see if the blade came loose. If not you may have hit something pushing the metal in and causing the blade to hit the deck. Happens to me on my rider when I hit a root of some trees I have in my yard. The blad is up a little higher than the deck and is makes an ungodly racket!!! I usually get a adjustable wrench and bend the metal back in shape.

Check for a sheared flywheel key. One way to check is to move the piston to top dead center and look at the position of the magnets on the stator in relation to the poles on the magneto. If the positions aren't very close at TDC, the flywheel key is most likely sheared, which is why you are not getting spark. Did the tractor blades hit anything hard lately when mowing? The key is made of soft metal so that if something like that happens, it will fail before the crankshaft gets bent or to prevent heavier damage. Anyway, you might want to check it out. Hope this helped and best wishes.

Push the clutch all the way down and try to start, does it crank over?
Let me know.
Regards,